WILBERT

Description: Extreme isotopologue disequilibrium in molecular SIMS species during SHRIMP geochronology Charles W. Magee Jr., Martin Danišík, and Terry Mernagh Geosci. Instrum. Method. Data Syst., 6, 523-536, https://doi.org/10.5194/gi-6-523-2017, 2017 The paper demonstrates that isotopologue disequilibrium can be created in the SIMS ionization process, and that the specific conditions under which it is created during the oxygen bombardment of geological materials are consistent with known conditions where traditional interrelationships between ion abundances break down. Further study to determine the degree of radiation dosage at which extreme disequilibrium appears involved Raman and helium dating on a variety of well-characterized zircons.

Description: Evaluating four gap-filling methods for eddy covariance measurements of evapotranspiration over hilly crop fields Nissaf Boudhina, Rim Zitouna-Chebbi, Insaf Mekki, Frédéric Jacob, Nétij Ben Mechlia, Moncef Masmoudi, and Laurent Prévot Geosci. Instrum. Method. Data Syst. Discuss., https//doi.org/10.5194/gi-2017-44,2017 Manuscript under review for GI (discussion: open, 1 comment) Estimating evapotranspiration in hilly watersheds is paramount for managing water resources, especially in semi-arid regions. Eddy covariance (EC) technique allows continuous measurements of latent heat flux LE. However, time series of EC measurements often experience large portions of missing data, because of instrumental dysfunctions or quality filtering. Existing gap-filling methods are questionable over hilly crop fields, because of changes in airflow inclination and subsequent aerodynamic properties. We evaluated the performances of different gap-filling methods before and after tailoring to conditions of hilly crop fields. The tailoring consisted of beforehand splitting the LE time series on the basis of upslope and downslope winds. The experiment was setup within an agricultural hilly watershed in northeastern Tunisia. EC measurements were collected throughout the growth cycle of three wheat crops, two of them located in adjacent fields on opposite hillslopes, and the third one located in a flat field. We considered four gap-filling methods: the REddyProc method, the linear regression between LE and net radiation Rn, the multi-linear regression of LE against the other energy fluxes, and the use of evaporative fraction EF. Regardless of method, the splitting of the LE time series did not impact the gap filling rate, and it might improve the accuracies on LE retrievals in some cases. Regardless of method, the obtained accuracies on LE estimates after gap filling were close to instrumental accuracies, and were comparable to those reported in previous studies over flat and mountainous terrains. Overall, REddyProc was the most appropriate method, for both gap filling rate and retrieval accuracy. Thus, it seems possible to conduct gap-filling for LE time series collected over hilly crop fields, provided the LE time series are beforehand split on the basis of upslope / downslope winds. Future works should address consecutive vegetation growth cycles for a larger panel of conditions in terms of climate, vegetation and water status.

Description: Total Global Solar Radiation Estimation with Relative Humidity and Air Temperature Extremes in Ireland and Holland Can Ekici and Ismail Teke Geosci. Instrum. Method. Data Syst. Discuss., https//doi.org/10.5194/gi-2017-52,2017 Revised manuscript accepted for GI (discussion: closed, 8 comments) - This study aimed to calibrate some of the existing models in the literature for estimating daily total global solar radiation parameter using available measuring records (maximum and minimum air temperatures) and three new models are developed based on maximum and minimum air temperatures and relative humidity. - In this study, three new models that are based on the relative humidity and the difference between maximum and minimum air temperatures were suggested.

Description: Data quality control and tools in passive seismic experiments exemplified on the Czech broadband seismic pool MOBNET in the AlpArray collaborative project Luděk Vecsey, Jaroslava Plomerová, Petr Jedlička, Helena Munzarová, Vladislav Babuška, and the AlpArray working group Geosci. Instrum. Method. Data Syst., 6, 505-521, https://doi.org/10.5194/gi-6-505-2017, 2017 This paper focuses on major issues related to data reliability and MOBNET network performance in the AlpArray seismic experiments. We present both new hardware and software tools that help to assure the high-quality standard of broadband seismic data. Special attention is paid to issues like a detection of sensor misorientation, timing problems, exchange of record components and/or their polarity reversal, sensor mass centring, or anomalous channel amplitudes due to imperfect gain.

Description: Development of a full-waveform voltage and current recording device for multichannel transient electromagnetic transmitters Xinyue Zhang, Qisheng Zhang, Meng Wang, Qiang Kong, Shengquan Zhang, Ruihao He, Shenghui Liu, Shuhan Li, and Zhenzhong Yuan Geosci. Instrum. Method. Data Syst., 6, 495-503, https://doi.org/10.5194/gi-6-495-2017, 2017 We believe that our study full-waveform voltage and current recording device for MTEM transmitters makes a significant contribution to the literature because this full-waveform recording device can be used to monitor the high-power, full-waveform voltages and currents of MTEM transmitters. It has high precision, finer edge details, low noise, and other advantages. Hence, it can be used for real-time recording and transmission to the receiver for coherent demodulation.

Description: Isca, v1.0: a framework for the global modelling of the atmospheres of Earth and other planets at varying levels of complexity Geoffrey K. Vallis, Greg Colyer, Ruth Geen, Edwin Gerber, Martin Jucker, Penelope Maher, Alexander Paterson, Marianne Pietschnig, James Penn, and Stephen I. Thomson Geosci. Model Dev., 11, 843-859, https://doi.org/10.5194/gmd-11-843-2018, 2018 The models that are used to describe the atmospheres of Earth and other planets are often very complicated. Although this is necessary for such things as weather prediction, it does not help in understanding. Furthermore, when studying other planets, there are insufficient data to warrant the use of complicated models. We have developed a framework that allows the construction of models of appropriate complexity for the problem at hand, and thus helps to actually model these atmospheres.

Description: GemPy 1.0: open-source stochastic geological modeling and inversion Miguel de la Varga, Alexander Schaaf, and Florian Wellmann Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-61,2018 Manuscript under review for GMD (discussion: open, 0 comments) GemPy is an open-source, Python-based 3-D structural geological modeling software, which allows the implicit (i.e. automatic) creation of complex geological models from interface and orientation data. GemPy is implemented in the programming language Python, making use of a highly efficient underlying library – theano for efficient code generation that performs automatic differentiation. This enables the link to Machine Learning and Bayesian inference frameworks.

Description: A fire model with distinct crop, pasture, and non-agricultural burning: use of new data and a model-fitting algorithm for FINAL.1 Sam S. Rabin, Daniel S. Ward, Sergey L. Malyshev, Brian I. Magi, Elena Shevliakova, and Stephen W. Pacala Geosci. Model Dev., 11, 815-842, https://doi.org/10.5194/gmd-11-815-2018, 2018 This paper describes a new fire model that for the first time simulates how fire is used on cropland and pasture in the modern day, as imposed using a recently developed dataset. A non-agricultural fire module is fit algorithmically against non-agricultural burned area. Fitting improves performance and the general global pattern of fire is represented, but some gaps remain. The novel separation of agricultural burning from other fire may necessitate new design thinking in the future.

Description: Development and evaluation of a variably saturated flow model in the global E3SM Land Model (ELM) Version 1.0 Gautam Bisht, William J. Riley, Glenn E. Hammond, and David M. Lorenzetti Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-44,2018 Manuscript under review for GMD (discussion: open, 0 comments) Most existing global land surface models used to study impacts of climate change on water resources, routinely use different employ different models for near-surface unsaturated soil and the deeper groundwater table. We developed a model that uses unified treatment of soil hydrologic processes throughout the entire soil column. Using a calibrated drainage parameter, the new model is able to correctly predicted deep water table depth as reported in an observationally-constrained global dataset.

Description: Simulating ectomycorrhiza in boreal forests: implementing ectomycorrhizal fungi model MYCOFON in CoupModel (v5) Hongxing He, Astrid Meyer, Per-Erik Jansson, Magnus Svensson, Tobias Rütting, and Leif Klemedtsson Geosci. Model Dev., 11, 725-751, https://doi.org/10.5194/gmd-11-725-2018, 2018 Ectomycorrhizal fungi (ECM) have shown a major impact on forest C and N cycles, but are currently neglected in most ecosystem models. We thus implemented the previously developed ectomycorrhizal fungi model, MYCOFON, into a well-established ecosystem model, CoupModel. This paper describes the key components and features of Coup-MYCOFON. The new version of CoupModel can now simulate C and N fluxes and pools, explicitly accounting for links and feedbacks among plant, soil, and ECM.

Description: Establishing a sediment budget in the newly created “Kleine Noordwaard” wetland area in the Rhine–Meuse delta Eveline Christien van der Deijl, Marcel van der Perk, and Hans Middelkoop Earth Surf. Dynam., 6, 187-201, https://doi.org/10.5194/esurf-6-187-2018, 2018 To study the effectiveness of river delta restoration, we used field observations and elevation data to quantify the magnitude and spatial patterns of aggradation and erosion in a restored wetland in the Rhine-Meuse delta. Erosion and aggradation rates decrease over time, but aggradation compensates for sea-level rise and soil subsidence. Channels in the centre had aggraded, whereas the inlet and outlet eroded. Furthermore, sediment is in general uniformly distributed over the intertidal area.

Description: Establishing a sediment budget in the newly created “Kleine Noordwaard” wetland area in the Rhine–Meuse delta Eveline Christien van der Deijl, Marcel van der Perk, and Hans Middelkoop Earth Surf. Dynam., 6, 187-201, https://doi.org/10.5194/esurf-6-187-2018, 2018 To study the effectiveness of river delta restoration, we used field observations and elevation data to quantify the magnitude and spatial patterns of aggradation and erosion in a restored wetland in the Rhine-Meuse delta. Erosion and aggradation rates decrease over time, but aggradation compensates for sea-level rise and soil subsidence. Channels in the centre had aggraded, whereas the inlet and outlet eroded. Furthermore, sediment is in general uniformly distributed over the intertidal area.

Description: Long-term ice phenology records from eastern–central Europe Katalin Takács, Zoltán Kern, and László Pásztor Earth Syst. Sci. Data, 10, 391-404, https://doi.org/10.5194/essd-10-391-2018, 2018 Annual ice phenology was compiled for the largest river (Danube) and lake (Balaton) in eastern–central Europe back to AD 1774 and AD 1885, respectively. The dates of the first appearance of ice and freeze-up have shifted to later. Break-up and ice-off have shifted to earlier, except break-up on Lake Balaton. The derived centennial records of freshwater cryophenology for the Danube and Balaton are readily available for detailed analysis of the temporal trends or other climatological purposes.

Description: Dynamic magnification factors for tree blow-down by powder snow avalanche air blasts Perry Bartelt, Peter Bebi, Thomas Feistl, Othmar Buser, and Andrin Caviezel Nat. Hazards Earth Syst. Sci., 18, 759-764, https://doi.org/10.5194/nhess-18-759-2018, 2018 We study how short duration powder avalanche blasts break and overturn tall trees. Tree blow-down is often used to back-calculate avalanche pressure and therefore constrain avalanche flow velocity and motion. We find that tall trees are susceptible to avalanche air blasts because the duration of the air blast is near to the period of vibration of tall trees. Dynamic magnification factors should therefore be considered when back-calculating powder avalanche impact pressures.

Description: Dynamic magnification factors for tree blow-down by powder snow avalanche air blasts Perry Bartelt, Peter Bebi, Thomas Feistl, Othmar Buser, and Andrin Caviezel Nat. Hazards Earth Syst. Sci., 18, 759-764, https://doi.org/10.5194/nhess-18-759-2018, 2018 We study how short duration powder avalanche blasts break and overturn tall trees. Tree blow-down is often used to back-calculate avalanche pressure and therefore constrain avalanche flow velocity and motion. We find that tall trees are susceptible to avalanche air blasts because the duration of the air blast is near to the period of vibration of tall trees. Dynamic magnification factors should therefore be considered when back-calculating powder avalanche impact pressures.

Description: Raindrop fall velocities from an optical array probe and 2-D video disdrometer Viswanathan Bringi, Merhala Thurai, and Darrel Baumgardner Atmos. Meas. Tech., 11, 1377-1384, https://doi.org/10.5194/amt-11-1377-2018, 2018 Raindrop fall velocities are important for rain rate estimation, soil erosion studies and in numerical modelling of rain formation in clouds. The assumption that the fall velocity is uniquely related to drop size is made inherently based on laboratory measurements under still air conditions from nearly 68 years ago. There have been very few measurements of drop fall speeds in natural rain under both still and turbulent wind conditions. We report on fall speed measurements in natural rain shafts.

Description: Characterization of blackbody inhomogeneity and its effect on the retrieval results of the GLORIA instrument Anne Kleinert, Isabell Krisch, Jörn Ungermann, Albert Adibekyan, Berndt Gutschwager, and Christian Monte Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2018-59,2018 Manuscript under review for AMT (discussion: open, 0 comments) This study investigates the required accuracy of radiometric calibration sources for remote sensing instruments to properly resolve decadal trends of climate relevant trace species like ozone, water vapor and temperature. The required temperature knowledge of the calibration source is in the order of 100 mK. This is demonstrated by a Monte-Carlo simulation. The results are confirmed using real measurements acquired by the GLORIA instrument.

Description: Wind Turbine Wake Measurements with Automatically Adjusting Scanning Trajectories in a Multi-Doppler Lidar Setup Norman Wildmann, Nikola Vasiljevic, and Thomas Gerz Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2018-55,2018 Manuscript under review for AMT (discussion: open, 0 comments) Wind turbines extract energy from the flow which manifests in a region of lower wind speeds and increased turbulence downstream of the rotor, the so-called wake. Understanding the characteristics of the wake is a key challenge for wind energy research. A new strategy to measure the wind in the wake with three synchronized lidar instruments is presented. The measurement points are automatically adapted to the prevailing wind direction to get a continuous monitoring of wake properties.

Description: Airborne limb-imaging measurements of temperature, HNO 3 , O 3 , ClONO 2 , H 2 O and CFC-12 during the Arctic winter 2015/16: characterization, in-situ validation and comparison to Aura/MLS Sören Johansson, Wolfgang Woiwode, Michael Höpfner, Felix Friedl-Vallon, Anne Kleinert, Erik Kretschmer, Thomas Latzko, Johannes Orphal, Peter Preusse, Jörn Ungermann, Michelle L. Santee, Tina Jurkat-Witschas, Andreas Marsing, Christiane Voigt, Andreas Giez, Martina Krämer, Christian Rolf, Andreas Zahn, Andreas Engel, Björn-Martin Sinnhuber, and Hermann Oelhaf Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2018-52,2018 Manuscript under review for AMT (discussion: open, 0 comments) We present two dimensional cross sections of temperature, HNO 3 , O 3 , ClONO 2 , H 2 O and CFC-12 from measurements of the GLORIA infrared limb imager during the POLSTRACC/GW-LCYCLE/SALSA aircraft campaigns in the Arctic winter 2015/16. GLORIA sounded the atmosphere between 5–14 km with vertical resolutions of 0.4–1 km. Estimated errors are in the range of 1–2 K (temperature) and 10–20 % (trace gases). Comparisons to in-situ instruments onboard the aircraft and to Aura/MLS are shown.

Description: Reduction of ZTD outliers through improved GNSS data processing and screening strategies Katarzyna Stepniak, Olivier Bock, and Pawel Wielgosz Atmos. Meas. Tech., 11, 1347-1361, https://doi.org/10.5194/amt-11-1347-2018, 2018 Though Global Navigation Satellite System (GNSS) data processing has been significantly improved over the years, it is still commonly observed that zenith tropospheric delay (ZTD) estimates contain many outliers which are detrimental to meteorological and climatological applications. In this paper, we show that ZTD outliers in double-difference processing are mostly caused by sub-daily data gaps at reference stations, which cause disconnections of clusters of stations from the reference network and common mode biases due to the strong correlation between stations in short baselines. They can reach a few centimetres in ZTD and usually coincide with a jump in formal errors. The magnitude and sign of these biases are impossible to predict because they depend on different errors in the observations and on the geometry of the baselines. We elaborate and test a new baseline strategy which solves this problem and significantly reduces the number of outliers compared to the standard strategy commonly used for positioning (e.g. determination of national reference frame) in which the pre-defined network is composed of a skeleton of reference stations to which secondary stations are connected in a star-like structure. The new strategy is also shown to perform better than the widely used strategy maximizing the number of observations available in many GNSS programs. The reason is that observations are maximized before processing, whereas the final number of used observations can be dramatically lower because of data rejection (screening) during the processing. The study relies on the analysis of 1 year of GPS (Global Positioning System) data from a regional network of 136 GNSS stations processed using Bernese GNSS Software v.5.2. A post-processing screening procedure is also proposed to detect and remove a few outliers which may still remain due to short data gaps. It is based on a combination of range checks and outlier checks of ZTD and formal errors. The accuracy of the final screened GPS ZTD estimates is assessed by comparison to ERA-Interim reanalysis.

Description: The importance of surface reflectance anisotropy for cloud and NO 2 retrievals from GOME-2 and OMI Alba Lorente, K. Folkert Boersma, Piet Stammes, L. Gijsbert Tilstra, Andreas Richter, Huan Yu, Said Kharbouche, and Jan-Peter Muller Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2018-32,2018 Manuscript under review for AMT (discussion: open, 0 comments) Light reflected by Earth’s surface is different in each direction: surfaces appear brighter or darker in certain viewing directions. Currently this effect is not accounted for in satellite retrievals, thus surface reflectance climatologies and cloud fractions show an East-West bias across orbits (GOME2,OMI). The effect for NO 2 measurements in partly cloudy scenes is substantial. We recommend to coherently account for this effect in UV/Vis sensors, and will be especially beneficial for TROPOMI.

Description: What historical landfast ice observations tell us about projected ice conditions in Arctic Archipelagoes and marginal seas under anthropogenic forcing Frédéric Laliberté, Stephen E. L. Howell, Jean-François Lemieux, Frédéric Dupont, and Ji Lei The Cryosphere Discuss., https//doi.org/10.5194/tc-2018-24,2018 Manuscript under review for TC (discussion: open, 0 comments) Ice that forms over marginal seas often gets anchored and becomes landfast. Landfast ice is fundamental to the local ecosystems, is of economic importance as they lead to hazardous seafaring conditions and is also a choice hunting ground for both the local population and large predators. Using observations and climate simulations, this study shows that, especially in the Canadian Arctic, landfast ice might be more resilient to climate change than is generally thought.

Description: High-resolution quantification of atmospheric CO 2 mixing ratios in the Greater Toronto Area, Canada Stephanie C. Pugliese, Jennifer G. Murphy, Felix R. Vogel, Michael D. Moran, Junhua Zhang, Qiong Zheng, Craig A. Stroud, Shuzhan Ren, Douglas Worthy, and Gregoire Broquet Atmos. Chem. Phys., 18, 3387-3401, https://doi.org/10.5194/acp-18-3387-2018, 2018 We developed the Southern Ontario CO 2 Emissions (SOCE) inventory, which identifies the spatial and temporal distribution (2.5 km and hourly, respectively) of CO 2 emissions from seven source sectors. When the SOCE inventory was used with a chemistry transport model, we found strong agreement between modelled and measured mixing ratios. We were able to quantify that natural gas combustion contributes 〉 80 % of CO 2 emissions at nighttime while on-road emissions contribute 〉 70 % during the day.

Description: Concentration, temporal variation and sources of black carbon in the Mount Everest region retrieved by real-time observation and simulation Xintong Chen, Shichang Kang, Zhiyuan Cong, Junhua Yang, and Yaoming Ma Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-183,2018 Manuscript under review for ACP (discussion: open, 0 comments) Based on the high-resolution measurement of black carbon (BC) at Qomolangma (Everest) station of Chinese Academy of Sciences during 15 May 2015 to 31 May 2017, we investigated the seasonal and diurnal variations of BC and its potential source regions. Monthly and daily mean BC concentrations reached the highest values in the pre-monsoon season which are at least one magnitude higher than the lowest values in the monsoon season. For the diurnal variation, BC concentrations were significantly greater from mid-night to noon in the pre-monsoon season and showed increasing trend in the afternoon in the non-monsoon seasons, implying the potential contribution from the long-range transport. In the monsoon season, BC concentrations appeared two peaks in the morning and after the noon, might be affected by the local anthropogenic activities. By analyzing the simulation results from the backward air-mass trajectories and the fire spots distribution from the MODIS data, we found that the seasonal cycle of BC was significantly influenced by atmospheric circulation and combustion intensity in the Mt. Everest region. The transport mechanisms of BC were revealed using WRF-Chem simulation during severe pollution episodes. For the pollution event in the monsoon season, BC aerosols in South Asia could be uplifted and transported to the Mt. Everest region by the southward winds in the upper atmosphere. However, for the events in the pre-monsoon season, BC from northern India was brought and concentrated in the southern slope of the Himalayas by the northwesterly winds in the lower atmosphere and then transported across the Himalayas by the mountain-valley wind, while relatively less BC from northwestern India and Central Asia could be transported to the Mt. Everest region by the westerly winds in the upper atmosphere.

Description: Monoterpene chemical speciation in a tropical rainforest:variation with season, height, and time of dayat the Amazon Tall Tower Observatory (ATTO) Ana María Yáñez-Serrano, Anke Christine Nölscher, Efstratios Bourtsoukidis, Eliane Gomes Alves, Laurens Ganzeveld, Boris Bonn, Stefan Wolff, Marta Sa, Marcia Yamasoe, Jonathan Williams, Meinrat O. Andreae, and Jürgen Kesselmeier Atmos. Chem. Phys., 18, 3403-3418, https://doi.org/10.5194/acp-18-3403-2018, 2018 This study shows the measurements of concentration of different monoterpene species in terms of height, time of day and season. Speciation seems similar during the dry seasons but changes with season. Furthermore, reactivity with the different oxidants demonstrated that a higher abundance of a monoterpene species does not automatically imply higher reactivity and that the most abundant monoterpene may not be the most atmospheric chemically relevant compound.

Description: The vapor pressure over nano-crystalline ice Mario Nachbar, Denis Duft, and Thomas Leisner Atmos. Chem. Phys., 18, 3419-3431, https://doi.org/10.5194/acp-18-3419-2018, 2018 The crystallization process of amorphous ice below 160 K forms nano-crystalline ice. We report high-quality vapor pressure measurements over ice crystallized from amorphous ice below 160 K. We show that the vapor pressure is increased by more than 100 % compared to bulk crystalline ice and that amorphous ice always forms first, followed by the crystallization of nano-crystalline ice. Our findings are relevant for cold ice clouds in the atmospheres of planets, e.g., Earth and Mars.

Description: Non-methane organic gas emissions from biomass burning: identification, quantification, and emission factors from PTR-ToF during the FIREX 2016 laboratory experiment Abigail R. Koss, Kanako Sekimoto, Jessica B. Gilman, Vanessa Selimovic, Matthew M. Coggon, Kyle J. Zarzana, Bin Yuan, Brian M. Lerner, Steven S. Brown, Jose L. Jimenez, Jordan Krechmer, James M. Roberts, Carsten Warneke, Robert J. Yokelson, and Joost de Gouw Atmos. Chem. Phys., 18, 3299-3319, https://doi.org/10.5194/acp-18-3299-2018, 2018 Non-methane organic gases (NMOGs) were detected by proton-transfer-reaction mass spectrometry (PTR-ToF) during an extensive laboratory characterization of wildfire emissions. Identifications for PTR-ToF ion masses are proposed and supported by a combination of techniques. Overall excellent agreement with other instrumentation is shown. Scalable emission factors and ratios are reported for many newly reported reactive species. An analysis of chemical characteristics is presented.

Description: High-resolution quantification of atmospheric CO 2 mixing ratios in the Greater Toronto Area, Canada Stephanie C. Pugliese, Jennifer G. Murphy, Felix R. Vogel, Michael D. Moran, Junhua Zhang, Qiong Zheng, Craig A. Stroud, Shuzhan Ren, Douglas Worthy, and Gregoire Broquet Atmos. Chem. Phys., 18, 3387-3401, https://doi.org/10.5194/acp-18-3387-2018, 2018 We developed the Southern Ontario CO 2 Emissions (SOCE) inventory, which identifies the spatial and temporal distribution (2.5 km and hourly, respectively) of CO 2 emissions from seven source sectors. When the SOCE inventory was used with a chemistry transport model, we found strong agreement between modelled and measured mixing ratios. We were able to quantify that natural gas combustion contributes 〉 80 % of CO 2 emissions at nighttime while on-road emissions contribute 〉 70 % during the day.

Description: Evaluation of stratospheric age of air from CF 4 , C 2 F 6 , C 3 F 8 , CHF 3 , HFC-125, HFC-227ea and SF 6 ; implications for the calculations of halocarbon lifetimes, fractional release factors and ozone depletion potentials Emma Leedham Elvidge, Harald Bönisch, Carl A. M. Brenninkmeijer, Andreas Engel, Paul J. Fraser, Eileen Gallacher, Ray Langenfelds, Jens Mühle, David E. Oram, Eric A. Ray, Anna R. Ridley, Thomas Röckmann, William T. Sturges, Ray F. Weiss, and Johannes C. Laube Atmos. Chem. Phys., 18, 3369-3385, https://doi.org/10.5194/acp-18-3369-2018, 2018 Chemical species measured in stratospheric air can be used as proxies for stratospheric circulation changes which cannot be measured directly. A range of tracers is important to understand changing stratospheric dynamics. We demonstrate the suitability of PFCs and HFCs as tracers and support recent work that reduces the current stratospheric lifetime of SF 6 . Updates to policy-relevant parameters (e.g. stratospheric lifetime) linked to this change are provided for O 3 -depleting substances.

Description: Scaling properties reveal regulation of river flows in the Amazon through a forest reservoir Juan Fernando Salazar, Juan Camilo Villegas, Angela María Rendón, Estiven Rodríguez, Isabel Hoyos, Daniel Mercado-Bettín, and Germán Poveda Hydrol. Earth Syst. Sci., 22, 1735-1748, https://doi.org/10.5194/hess-22-1735-2018, 2018 River flow regimes are being altered by global change. Understanding the mechanisms behind such alterations is crucial for hydrological prediction. We introduce a novel interpretation of river flow metrics (scaling) that allows any river basin to be classified as regulated or unregulated, and to identify transitions between these states. We propose the forest reservoir hypothesis to explain how forest loss can force the Amazonian river basins from regulated to unregulated states.

Description: Hydraulic characterisation of iron-oxide-coated sand and gravel based on nuclear magnetic resonance relaxation mode analyses Stephan Costabel, Christoph Weidner, Mike Müller-Petke, and Georg Houben Hydrol. Earth Syst. Sci., 22, 1713-1729, https://doi.org/10.5194/hess-22-1713-2018, 2018 Laboratory experiments using water-filled sand and gravel samples with significant contents of iron oxide coatings were performed to identify the relationship between effective hydraulic radius and nuclear magnetic resonance (NMR) response. Our interpretation approach for the NMR data leads to reliable estimates of hydraulic conductivity without calibration, but is limited to coarse material for physical reasons. An NMR-based observation system for iron clogging in boreholes is planned.

Description: Forest harvesting impacts on micrometeorological conditions and sediment transport activities in a humid periglacial environment Fumitoshi Imaizumi, Ryoko Nishii, Kenichi Ueno, and Kousei Kurobe Hydrol. Earth Syst. Sci. Discuss., https//doi.org/10.5194/hess-2018-64,2018 Manuscript under review for HESS (discussion: open, 0 comments) We investigated seasonal changes in sediment transport activities following forest harvesting in in a humid periglacial area. Removal of the forest canopy by forest harvesting alters the type of winter soil creep. Winter creep velocity of the ground surface sediment in the harvested site was significantly higher than that in the non-harvested site. Meanwhile, sediment flux on the hillslopes decreased in the harvested site because of capture of sediment by branches of harvested trees.

Description: Vegetation changes and water cycle in a changing environment Lixin Wang, Xiaohua Wei, Kevin Bishop, Alison D. Reeves, Nadia Ursino, and Rita Winkler Hydrol. Earth Syst. Sci., 22, 1731-1734, https://doi.org/10.5194/hess-22-1731-2018, 2018

Description: Characterizing drought in terms of changes in the precipitation–runoff relationship: a case study of the Loess Plateau, China Yuan Zhang, Xiaoming Feng, Xiaofeng Wang, and Bojie Fu Hydrol. Earth Syst. Sci., 22, 1749-1766, https://doi.org/10.5194/hess-22-1749-2018, 2018 We characterized drought by linking climate anomalies with the change in precipitation–runoff relationships in China's Loess Plateau, where drought is of major concern for revegetation. Multi-year drought causes a change in the precipitation–runoff relationship in this water limited area. The drought causing a decrease in runoff ratio is vital to ecosystem management. The revegetation in the Loess Plateau should live with the spatially varied drought.

Description: Scaling properties reveal regulation of river flows in the Amazon through a forest reservoir Juan Fernando Salazar, Juan Camilo Villegas, Angela María Rendón, Estiven Rodríguez, Isabel Hoyos, Daniel Mercado-Bettín, and Germán Poveda Hydrol. Earth Syst. Sci., 22, 1735-1748, https://doi.org/10.5194/hess-22-1735-2018, 2018 River flow regimes are being altered by global change. Understanding the mechanisms behind such alterations is crucial for hydrological prediction. We introduce a novel interpretation of river flow metrics (scaling) that allows any river basin to be classified as regulated or unregulated, and to identify transitions between these states. We propose the forest reservoir hypothesis to explain how forest loss can force the Amazonian river basins from regulated to unregulated states.

Description: The influence of long-term changes in canopy structure on rainfall interception loss: a case study in Speulderbos, the Netherlands César Cisneros Vaca, Christiaan van der Tol, and Chandra Prasad Ghimire Hydrol. Earth Syst. Sci. Discuss., https//doi.org/10.5194/hess-2018-54,2018 Manuscript under review for HESS (discussion: open, 0 comments) The evaporation of intercepted water by forests is a significant contributor to both the water and energy budget of the Earth. In many studies, a discrepancy in the water and energy budget is found: the energy that is needed for evaporation is larger than the available energy supplied by net radiation. In this study, we analyse the water and energy budget of a mature Douglas-fir stand in the Netherlands, for the two growing seasons of 2015 and 2016. Based on the wet-canopy water balance equation for these two growing seasons, derived interception losses were estimated to be 37 % and 39 % of gross rainfall, respectively. We further scrutinized eddy covariance energy balance data from these two consecutive growing seasons and found the average evaporation rate during wet canopy conditions was 0.20 mm h −1 . The source of energy for this wet-canopy evaporation was net radiation (35 %), a negative sensible heat flux (45 %) and a negative energy storage change (15 %). This confirms that the energy for wet-canopy evaporation is extracted from the biomass as well as the atmosphere. Moreover, the measured interception loss at the forest was similar to that measured at the same site years before ( I  = 38 %), when the forest was younger (29 years old, vs 55 years old in 2015). At that time, the forest was denser and had a higher canopy storage capacity (2.4 mm then vs 1.90 mm in 2015), but the aerodynamic conductance was lower (0.065 m s −1 then vs 0.105 m s −1 in 2015), and therefore past evaporation rates were lower than evaporation rates found in the present study (0.077 mm h −1 vs 0.20 mm h −1 in 2015). Our findings emphasize the importance of quantifying downward sensible heat flux and heat release from canopy biomass in tall forest in order to improve the quantification of evaporative fluxes in wet canopies.

Description: Regional soil erosion assessment based on a sample survey and geostatistics Shuiqing Yin, Zhengyuan Zhu, Li Wang, Baoyuan Liu, Yun Xie, Guannan Wang, and Yishan Li Hydrol. Earth Syst. Sci., 22, 1695-1712, https://doi.org/10.5194/hess-22-1695-2018, 2018 Soil erosion is one of the most significant environmental problems in China. From 2010 to 2012, the fourth national census for soil erosion sampled 32 364 PSUs (Primary Sampling Units, small watersheds) with the areas of 0.2–3 km 2 . Land use and soil erosion controlling factors including rainfall erosivity, soil erodibility, slope length, slope steepness, biological practice, engineering practice, and tillage practice for the PSUs were surveyed, and the soil loss rate for each land use in the PSUs was estimated using an empirical model, the Chinese Soil Loss Equation (CSLE). Though the information collected from the sample units can be aggregated to estimate soil erosion conditions on a large scale; the problem of estimating soil erosion condition on a regional scale has not been addressed well. The aim of this study is to introduce a new model-based regional soil erosion assessment method combining a sample survey and geostatistics. We compared seven spatial interpolation models based on the bivariate penalized spline over triangulation (BPST) method to generate a regional soil erosion assessment from the PSUs. Shaanxi Province (3116 PSUs) in China was selected for the comparison and assessment as it is one of the areas with the most serious erosion problem. Ten-fold cross-validation based on the PSU data showed the model assisted by the land use, rainfall erosivity factor ( R ), soil erodibility factor ( K ), slope steepness factor ( S ), and slope length factor ( L ) derived from a 1 : 10 000 topography map is the best one, with the model efficiency coefficient (ME) being 0.75 and the MSE being 55.8 % of that for the model assisted by the land use alone. Among four erosion factors as the covariates, the S  factor contributed the most information, followed by K  and L  factors, and R  factor made almost no contribution to the spatial estimation of soil loss. The L S factor derived from 30 or 90 m Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) data worsened the estimation when used as the covariates for the interpolation of soil loss. Due to the unavailability of a 1 : 10 000 topography map for the entire area in this study, the model assisted by the land use, R , and K  factors, with a resolution of 250 m, was used to generate the regional assessment of the soil erosion for Shaanxi Province. It demonstrated that 54.3 % of total land in Shaanxi Province had annual soil loss equal to or greater than 5 t ha −1  yr −1 . High (20–40 t ha −1  yr −1 ), severe (40–80 t ha −1  yr −1 ), and extreme ( 〉  80 t ha −1  yr −1 ) erosion occupied 14.0 % of the total land. The dry land and irrigated land, forest, shrubland, and grassland in Shaanxi Province had mean soil loss rates of 21.77, 3.51, 10.00, and 7.27 t ha −1  yr −1 , respectively. Annual soil loss was about 207.3 Mt in Shaanxi Province, with 68.9 % of soil loss originating from the farmlands and grasslands in Yan'an and Yulin districts in the northern Loess Plateau region and Ankang and Hanzhong districts in the southern Qingba mountainous region. This methodology provides a more accurate regional soil erosion assessment and can help policymakers to take effective measures to mediate soil erosion risks.

Description: Hydraulic characterisation of iron-oxide-coated sand and gravel based on nuclear magnetic resonance relaxation mode analyses Stephan Costabel, Christoph Weidner, Mike Müller-Petke, and Georg Houben Hydrol. Earth Syst. Sci., 22, 1713-1729, https://doi.org/10.5194/hess-22-1713-2018, 2018 Laboratory experiments using water-filled sand and gravel samples with significant contents of iron oxide coatings were performed to identify the relationship between effective hydraulic radius and nuclear magnetic resonance (NMR) response. Our interpretation approach for the NMR data leads to reliable estimates of hydraulic conductivity without calibration, but is limited to coarse material for physical reasons. An NMR-based observation system for iron clogging in boreholes is planned.

Description: The influence of long-term changes in canopy structure on rainfall interception loss: a case study in Speulderbos, the Netherlands César Cisneros Vaca, Christiaan van der Tol, and Chandra Prasad Ghimire Hydrol. Earth Syst. Sci. Discuss., https//doi.org/10.5194/hess-2018-54,2018 Manuscript under review for HESS (discussion: open, 0 comments) The evaporation of intercepted water by forests is a significant contributor to both the water and energy budget of the Earth. In many studies, a discrepancy in the water and energy budget is found: the energy that is needed for evaporation is larger than the available energy supplied by net radiation. In this study, we analyse the water and energy budget of a mature Douglas-fir stand in the Netherlands, for the two growing seasons of 2015 and 2016. Based on the wet-canopy water balance equation for these two growing seasons, derived interception losses were estimated to be 37 % and 39 % of gross rainfall, respectively. We further scrutinized eddy covariance energy balance data from these two consecutive growing seasons and found the average evaporation rate during wet canopy conditions was 0.20 mm h −1 . The source of energy for this wet-canopy evaporation was net radiation (35 %), a negative sensible heat flux (45 %) and a negative energy storage change (15 %). This confirms that the energy for wet-canopy evaporation is extracted from the biomass as well as the atmosphere. Moreover, the measured interception loss at the forest was similar to that measured at the same site years before ( I  = 38 %), when the forest was younger (29 years old, vs 55 years old in 2015). At that time, the forest was denser and had a higher canopy storage capacity (2.4 mm then vs 1.90 mm in 2015), but the aerodynamic conductance was lower (0.065 m s −1 then vs 0.105 m s −1 in 2015), and therefore past evaporation rates were lower than evaporation rates found in the present study (0.077 mm h −1 vs 0.20 mm h −1 in 2015). Our findings emphasize the importance of quantifying downward sensible heat flux and heat release from canopy biomass in tall forest in order to improve the quantification of evaporative fluxes in wet canopies.

Description: Regional soil erosion assessment based on a sample survey and geostatistics Shuiqing Yin, Zhengyuan Zhu, Li Wang, Baoyuan Liu, Yun Xie, Guannan Wang, and Yishan Li Hydrol. Earth Syst. Sci., 22, 1695-1712, https://doi.org/10.5194/hess-22-1695-2018, 2018 Soil erosion is one of the most significant environmental problems in China. From 2010 to 2012, the fourth national census for soil erosion sampled 32 364 PSUs (Primary Sampling Units, small watersheds) with the areas of 0.2–3 km 2 . Land use and soil erosion controlling factors including rainfall erosivity, soil erodibility, slope length, slope steepness, biological practice, engineering practice, and tillage practice for the PSUs were surveyed, and the soil loss rate for each land use in the PSUs was estimated using an empirical model, the Chinese Soil Loss Equation (CSLE). Though the information collected from the sample units can be aggregated to estimate soil erosion conditions on a large scale; the problem of estimating soil erosion condition on a regional scale has not been addressed well. The aim of this study is to introduce a new model-based regional soil erosion assessment method combining a sample survey and geostatistics. We compared seven spatial interpolation models based on the bivariate penalized spline over triangulation (BPST) method to generate a regional soil erosion assessment from the PSUs. Shaanxi Province (3116 PSUs) in China was selected for the comparison and assessment as it is one of the areas with the most serious erosion problem. Ten-fold cross-validation based on the PSU data showed the model assisted by the land use, rainfall erosivity factor ( R ), soil erodibility factor ( K ), slope steepness factor ( S ), and slope length factor ( L ) derived from a 1 : 10 000 topography map is the best one, with the model efficiency coefficient (ME) being 0.75 and the MSE being 55.8 % of that for the model assisted by the land use alone. Among four erosion factors as the covariates, the S  factor contributed the most information, followed by K  and L  factors, and R  factor made almost no contribution to the spatial estimation of soil loss. The L S factor derived from 30 or 90 m Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) data worsened the estimation when used as the covariates for the interpolation of soil loss. Due to the unavailability of a 1 : 10 000 topography map for the entire area in this study, the model assisted by the land use, R , and K  factors, with a resolution of 250 m, was used to generate the regional assessment of the soil erosion for Shaanxi Province. It demonstrated that 54.3 % of total land in Shaanxi Province had annual soil loss equal to or greater than 5 t ha −1  yr −1 . High (20–40 t ha −1  yr −1 ), severe (40–80 t ha −1  yr −1 ), and extreme ( 〉  80 t ha −1  yr −1 ) erosion occupied 14.0 % of the total land. The dry land and irrigated land, forest, shrubland, and grassland in Shaanxi Province had mean soil loss rates of 21.77, 3.51, 10.00, and 7.27 t ha −1  yr −1 , respectively. Annual soil loss was about 207.3 Mt in Shaanxi Province, with 68.9 % of soil loss originating from the farmlands and grasslands in Yan'an and Yulin districts in the northern Loess Plateau region and Ankang and Hanzhong districts in the southern Qingba mountainous region. This methodology provides a more accurate regional soil erosion assessment and can help policymakers to take effective measures to mediate soil erosion risks.

Description: Assessing the significance of Heidegger's Black Notebooks Jeff Malpas Geogr. Helv., 73, 109-114, https://doi.org/10.5194/gh-73-109-2018, 2018 The publication of Heidegger's Black Notebooks ( Schwarze Hefte ) has provoked a storm of controversy. Much of this has centred on the pro-Nazi and anti-Semitic comments the volumes contain. But these aspects of the Notebooks are perhaps the least surprising and important. This essay offers a summary overview of the issues to which the Notebooks give rise, at the same time as it also aims to provide a preliminary assessment of their overall significance, especially in relation to what they show about the nature and development of Heidegger's thinking from the early 1930s to the late 1940s.

Description: A global space-based stratospheric aerosol climatology: 1979–2016 Larry W. Thomason, Nicholas Ernest, Luis Millán, Landon Rieger, Adam Bourassa, Jean-Paul Vernier, Gloria Manney, Beiping Luo, Florian Arfeuille, and Thomas Peter Earth Syst. Sci. Data, 10, 469-492, https://doi.org/10.5194/essd-10-469-2018, 2018 We describe the construction of a continuous 38-year record of stratospheric aerosol optical properties. The Global Space-based Stratospheric Aerosol Climatology, or GloSSAC, provided the input data to the construction of the Climate Model Intercomparison Project stratospheric aerosol forcing data set (1979 to 2014) and is now extended through 2016. GloSSAC focuses on the the SAGE series of instruments through mid-2005 and on OSIRIS and CALIPSO after that time.

Description: The ESA GOME-Evolution “Climate” water vapor product: a homogenized time series of H 2 O columns from GOME, SCIAMACHY, and GOME-2 Steffen Beirle, Johannes Lampel, Yang Wang, Kornelia Mies, Steffen Dörner, Margherita Grossi, Diego Loyola, Angelika Dehn, Anja Danielczok, Marc Schröder, and Thomas Wagner Earth Syst. Sci. Data, 10, 449-468, https://doi.org/10.5194/essd-10-449-2018, 2018 We present time series of the global distribution of water vapor over more than 2 decades based on satellite measurements from different sensors. A particular focus is the consistency amongst the different sensors to avoid jumps from one instrument to another. This is reached by applying robust and simple retrieval settings consistently. The resulting Climate product allows the study of the temporal evolution of water vapor over the last 20 years on a global scale.

Description: A global space-based stratospheric aerosol climatology: 1979–2016 Larry W. Thomason, Nicholas Ernest, Luis Millán, Landon Rieger, Adam Bourassa, Jean-Paul Vernier, Gloria Manney, Beiping Luo, Florian Arfeuille, and Thomas Peter Earth Syst. Sci. Data, 10, 469-492, https://doi.org/10.5194/essd-10-469-2018, 2018 We describe the construction of a continuous 38-year record of stratospheric aerosol optical properties. The Global Space-based Stratospheric Aerosol Climatology, or GloSSAC, provided the input data to the construction of the Climate Model Intercomparison Project stratospheric aerosol forcing data set (1979 to 2014) and is now extended through 2016. GloSSAC focuses on the the SAGE series of instruments through mid-2005 and on OSIRIS and CALIPSO after that time.

Description: The ESA GOME-Evolution “Climate” water vapor product: a homogenized time series of H 2 O columns from GOME, SCIAMACHY, and GOME-2 Steffen Beirle, Johannes Lampel, Yang Wang, Kornelia Mies, Steffen Dörner, Margherita Grossi, Diego Loyola, Angelika Dehn, Anja Danielczok, Marc Schröder, and Thomas Wagner Earth Syst. Sci. Data, 10, 449-468, https://doi.org/10.5194/essd-10-449-2018, 2018 We present time series of the global distribution of water vapor over more than 2 decades based on satellite measurements from different sensors. A particular focus is the consistency amongst the different sensors to avoid jumps from one instrument to another. This is reached by applying robust and simple retrieval settings consistently. The resulting Climate product allows the study of the temporal evolution of water vapor over the last 20 years on a global scale.

Description: Global Carbon Budget 2017 Corinne Le Quéré, Robbie M. Andrew, Pierre Friedlingstein, Stephen Sitch, Julia Pongratz, Andrew C. Manning, Jan Ivar Korsbakken, Glen P. Peters, Josep G. Canadell, Robert B. Jackson, Thomas A. Boden, Pieter P. Tans, Oliver D. Andrews, Vivek K. Arora, Dorothee C. E. Bakker, Leticia Barbero, Meike Becker, Richard A. Betts, Laurent Bopp, Frédéric Chevallier, Louise P. Chini, Philippe Ciais, Catherine E. Cosca, Jessica Cross, Kim Currie, Thomas Gasser, Ian Harris, Judith Hauck, Vanessa Haverd, Richard A. Houghton, Christopher W. Hunt, George Hurtt, Tatiana Ilyina, Atul K. Jain, Etsushi Kato, Markus Kautz, Ralph F. Keeling, Kees Klein Goldewijk, Arne Körtzinger, Peter Landschützer, Nathalie Lefèvre, Andrew Lenton, Sebastian Lienert, Ivan Lima, Danica Lombardozzi, Nicolas Metzl, Frank Millero, Pedro M. S. Monteiro, David R. Munro, Julia E. M. S. Nabel, Shin-ichiro Nakaoka, Yukihiro Nojiri, X. Antonio Padin, Anna Peregon, Benjamin Pfeil, Denis Pierrot, Benjamin Poulter, Gregor Rehder, Janet Reimer, Christian Rödenbeck, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Benjamin D. Stocker, Hanqin Tian, Bronte Tilbrook, Francesco N. Tubiello, Ingrid T. van der Laan-Luijkx, Guido R. van der Werf, Steven van Heuven, Nicolas Viovy, Nicolas Vuichard, Anthony P. Walker, Andrew J. Watson, Andrew J. Wiltshire, Sönke Zaehle, and Dan Zhu Earth Syst. Sci. Data, 10, 405-448, https://doi.org/10.5194/essd-10-405-2018, 2018 The Global Carbon Budget 2017 describes data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. It is the 12th annual update and the 6th published in this journal.

Description: Global Carbon Budget 2017 Corinne Le Quéré, Robbie M. Andrew, Pierre Friedlingstein, Stephen Sitch, Julia Pongratz, Andrew C. Manning, Jan Ivar Korsbakken, Glen P. Peters, Josep G. Canadell, Robert B. Jackson, Thomas A. Boden, Pieter P. Tans, Oliver D. Andrews, Vivek K. Arora, Dorothee C. E. Bakker, Leticia Barbero, Meike Becker, Richard A. Betts, Laurent Bopp, Frédéric Chevallier, Louise P. Chini, Philippe Ciais, Catherine E. Cosca, Jessica Cross, Kim Currie, Thomas Gasser, Ian Harris, Judith Hauck, Vanessa Haverd, Richard A. Houghton, Christopher W. Hunt, George Hurtt, Tatiana Ilyina, Atul K. Jain, Etsushi Kato, Markus Kautz, Ralph F. Keeling, Kees Klein Goldewijk, Arne Körtzinger, Peter Landschützer, Nathalie Lefèvre, Andrew Lenton, Sebastian Lienert, Ivan Lima, Danica Lombardozzi, Nicolas Metzl, Frank Millero, Pedro M. S. Monteiro, David R. Munro, Julia E. M. S. Nabel, Shin-ichiro Nakaoka, Yukihiro Nojiri, X. Antonio Padin, Anna Peregon, Benjamin Pfeil, Denis Pierrot, Benjamin Poulter, Gregor Rehder, Janet Reimer, Christian Rödenbeck, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Benjamin D. Stocker, Hanqin Tian, Bronte Tilbrook, Francesco N. Tubiello, Ingrid T. van der Laan-Luijkx, Guido R. van der Werf, Steven van Heuven, Nicolas Viovy, Nicolas Vuichard, Anthony P. Walker, Andrew J. Watson, Andrew J. Wiltshire, Sönke Zaehle, and Dan Zhu Earth Syst. Sci. Data, 10, 405-448, https://doi.org/10.5194/essd-10-405-2018, 2018 The Global Carbon Budget 2017 describes data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. It is the 12th annual update and the 6th published in this journal.

Description: Estimating aboveground carbon density and its uncertainty in Borneo’s structurally complex tropical forests using airborne laser scanning Tommaso Jucker, Gregory P. Asner, Michele Dalponte, Philip Brodrick, Christopher D. Philipson, Nick Vaughn, Yit Arn Teh, Craig Brelsford, David F. R. P. Burslem, Nicolas J. Deere, Robert M. Ewers, Jakub Kvasnica, Simon L. Lewis, Yadvinder Malhi, Sol Milne, Reuben Nilus, Marion Pfeifer, Oliver L. Phillips, Lan Qie, Nathan Renneboog, Glen Reynolds, Terhi Riutta, Matthew J. Struebig, Martin Svátek, Edgar C. Turner, and David A. Coomes Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-74,2018 Manuscript under review for BG (discussion: open, 0 comments) Efforts to protect tropical forests hinge on recognising the ecosystem services they provide, including their ability to store carbon. Airborne Laser Scanning (ALS) captures information on forest structure, allowing forest carbon to be mapped. By combining ALS imagery with data from 173 forest plots on the island of Borneo, we develop a simple-yet-general model for estimating forest carbon stocks. Our model underpins ongoing efforts to restore Borneo’s unique tropical forests.

Description: Ecosystem fluxes of carbonyl sulfide in an old-growth forest: temporal dynamics and responses to diffuse radiation and heat waves Bharat Rastogi, Max Berkelhammer, Sonia Wharton, Mary E. Whelan, Frederick C. Meinzer, David Noone, and Christopher J. Still Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-85,2018 Manuscript under review for BG (discussion: open, 0 comments) Measurements of carbonyl sulfide (OCS) have recently gained prominence as an independent tracer for gross primary productivity, which is usually modelled by partitioning net CO 2 fluxes. Here, we present a simple empirical model for estimating ecosystem scale OCS fluxes for a temperate old-growth forest, and find that sink strength is highly dependent on soil moisture and the diffuse fraction of downwelling radiation. We also examine the response of OCS and CO 2 fluxes to sequential heatwaves.

Description: Evolution of fractality in space plasmas of interest to geomagnetic activity Víctor Muñoz, Macarena Domínguez, Juan Alejandro Valdivia, Simon Good, Giuseppina Nigro, and Vincenzo Carbone Nonlin. Processes Geophys., 25, 207-216, https://doi.org/10.5194/npg-25-207-2018, 2018 Fractals are self-similar objects (which look the same at all scales), whose dimensions can be noninteger. They are mathematical concepts, useful to describe various physical systems, as the fractal dimension is a measure of their complexity. In this paper we study how these concepts can be applied to some problems in space plasmas, such as the activity of the Earth's magnetosphere, simulations of plasma turbulence, or identification of magnetic structures ejected from the Sun.

Description: Evolution of fractality in space plasmas of interest to geomagnetic activity Víctor Muñoz, Macarena Domínguez, Juan Alejandro Valdivia, Simon Good, Giuseppina Nigro, and Vincenzo Carbone Nonlin. Processes Geophys., 25, 207-216, https://doi.org/10.5194/npg-25-207-2018, 2018 Fractals are self-similar objects (which look the same at all scales), whose dimensions can be noninteger. They are mathematical concepts, useful to describe various physical systems, as the fractal dimension is a measure of their complexity. In this paper we study how these concepts can be applied to some problems in space plasmas, such as the activity of the Earth's magnetosphere, simulations of plasma turbulence, or identification of magnetic structures ejected from the Sun.

Description: A Statistical Mechanical Approach for the Parametrization of the Coupling in a Fast-Slow System Gabriele Vissio and Valerio Lucarini Nonlin. Processes Geophys. Discuss., https//doi.org/10.5194/npg-2018-16,2018 Manuscript under review for NPG (discussion: open, 0 comments) Constructing accurate, flexible, and efficient parametrizations is one of the great challenges in the numerical modelling of geophysical fluids. We consider here the simple yet paradigmatic case of a Lorenz 84 model forced by a Lorenz 63 model and derive a parametrization using a recently developed statistical mechanical methodology based on the Ruelle response theory. We derive an expression for the deterministic and the stochastic component of the parametrization and we show that the approach allows for dealing seamlessly with the case of the Lorenz 63 being a fast as well as a slow forcing compared to the characteristic time scales of the Lorenz 84 model. We test our results using both standard metrics based on the moments of the variables of interest as well as Wasserstein distance between the projected measure of the original system on the Lorenz 84 model variables and the measure of the parametrized one. By testing our methods on reduced phase spaces obtained by projection, we find support to the idea that comparisons based on the Wasserstein distance might be of relevance in many applications despite the curse of dimensionality.

Description: A Statistical Mechanical Approach for the Parametrization of the Coupling in a Fast-Slow System Gabriele Vissio and Valerio Lucarini Nonlin. Processes Geophys. Discuss., https//doi.org/10.5194/npg-2018-16,2018 Manuscript under review for NPG (discussion: open, 0 comments) Constructing accurate, flexible, and efficient parametrizations is one of the great challenges in the numerical modelling of geophysical fluids. We consider here the simple yet paradigmatic case of a Lorenz 84 model forced by a Lorenz 63 model and derive a parametrization using a recently developed statistical mechanical methodology based on the Ruelle response theory. We derive an expression for the deterministic and the stochastic component of the parametrization and we show that the approach allows for dealing seamlessly with the case of the Lorenz 63 being a fast as well as a slow forcing compared to the characteristic time scales of the Lorenz 84 model. We test our results using both standard metrics based on the moments of the variables of interest as well as Wasserstein distance between the projected measure of the original system on the Lorenz 84 model variables and the measure of the parametrized one. By testing our methods on reduced phase spaces obtained by projection, we find support to the idea that comparisons based on the Wasserstein distance might be of relevance in many applications despite the curse of dimensionality.

Description: Ca-rich garnets and associated symplectites in mafic peraluminous granulites from the Gföhl Nappe System, Austria Konstantin Petrakakis, Nathalie Schuster-Bourgin, Gerlinde Habler, and Rainer Abart Solid Earth Discuss., https//doi.org/10.5194/se-2018-18,2018 Manuscript under review for SE (discussion: open, 0 comments) Aluminum-rich granulites from Austria contain large garnets with kyanite inclusions. Garnets are built up from compositionally different types. They are replaced partially by various symplectites. Thermodynamic analysis points to metasomatic alteration and rock decompression due to tectonic transport at high temperatures from deep to middle crustal levels. The various symplectites were formed after decompression during cooling within a short time interval of less than 500 years.

Description: Ca-rich garnets and associated symplectites in mafic peraluminous granulites from the Gföhl Nappe System, Austria Konstantin Petrakakis, Nathalie Schuster-Bourgin, Gerlinde Habler, and Rainer Abart Solid Earth Discuss., https//doi.org/10.5194/se-2018-18,2018 Manuscript under review for SE (discussion: open, 0 comments) Aluminum-rich granulites from Austria contain large garnets with kyanite inclusions. Garnets are built up from compositionally different types. They are replaced partially by various symplectites. Thermodynamic analysis points to metasomatic alteration and rock decompression due to tectonic transport at high temperatures from deep to middle crustal levels. The various symplectites were formed after decompression during cooling within a short time interval of less than 500 years.

Description: Sunlight, Clouds, Sea Ice and Albedo: The Umbrella Versus the Blanket Donald K. Perovich The Cryosphere Discuss., https//doi.org/10.5194/tc-2018-47,2018 Manuscript under review for TC (discussion: open, 0 comments) The balance of longwave and shortwave radiation plays a central role in the summer melt of Arctic sea ice. It is governed by clouds and surface albedo. The basic question is what causes more melting, sunny skies or cloudy skies. It depends on the albedo of the ice surface. For snow covered or bare ice, sunny skies always result in less radiative heat input. In contrast, the open ocean always has, and melt ponds usually have, more radiative input under sunny skies than cloudy skies.

Description: Improving gridded snow water equivalent products in British Columbia, Canada: multi-source data fusion by neural network models Andrew M. Snauffer, William W. Hsieh, Alex J. Cannon, and Markus A. Schnorbus The Cryosphere, 12, 891-905, https://doi.org/10.5194/tc-12-891-2018, 2018 Estimating winter snowpack throughout British Columbia is challenging due to the complex terrain, thick forests, and high snow accumulations present. This paper describes a way to make better snow estimates by combining publicly available data using machine learning, a branch of artificial intelligence research. These improved estimates will help water resources managers better plan for changes in rivers and lakes fed by spring snowmelt and will aid other research that supports such planning.

Description: Improving gridded snow water equivalent products in British Columbia, Canada: multi-source data fusion by neural network models Andrew M. Snauffer, William W. Hsieh, Alex J. Cannon, and Markus A. Schnorbus The Cryosphere, 12, 891-905, https://doi.org/10.5194/tc-12-891-2018, 2018 Estimating winter snowpack throughout British Columbia is challenging due to the complex terrain, thick forests, and high snow accumulations present. This paper describes a way to make better snow estimates by combining publicly available data using machine learning, a branch of artificial intelligence research. These improved estimates will help water resources managers better plan for changes in rivers and lakes fed by spring snowmelt and will aid other research that supports such planning.

Description: Sunlight, Clouds, Sea Ice and Albedo: The Umbrella Versus the Blanket Donald K. Perovich The Cryosphere Discuss., https//doi.org/10.5194/tc-2018-47,2018 Manuscript under review for TC (discussion: open, 0 comments) The balance of longwave and shortwave radiation plays a central role in the summer melt of Arctic sea ice. It is governed by clouds and surface albedo. The basic question is what causes more melting, sunny skies or cloudy skies. It depends on the albedo of the ice surface. For snow covered or bare ice, sunny skies always result in less radiative heat input. In contrast, the open ocean always has, and melt ponds usually have, more radiative input under sunny skies than cloudy skies.

Description: Using SAR satellite data time series for regional glacier mapping Solveig H. Winsvold, Andreas Kääb, Christopher Nuth, Liss M. Andreassen, Ward J. J. van Pelt, and Thomas Schellenberger The Cryosphere, 12, 867-890, https://doi.org/10.5194/tc-12-867-2018, 2018 With dense SAR satellite data time series it is possible to map surface and subsurface glacier properties that vary in time. On Sentinel-1A and RADARSAT-2 backscatter time series images over mainland Norway and Svalbard, we outline how to map glaciers using descriptive methods. We present five application scenarios. The first shows potential for tracking transient snow lines with SAR backscatter time series and correlates with both optical satellite images (Sentinel-2A and Landsat 8) and equilibrium line altitudes derived from in situ surface mass balance data. In the second application scenario, time series representation of glacier facies corresponding to SAR glacier zones shows potential for a more accurate delineation of the zones and how they change in time. The third application scenario investigates the firn evolution using dense SAR backscatter time series together with a coupled energy balance and multilayer firn model. We find strong correlation between backscatter signals with both the modeled firn air content and modeled wetness in the firn. In the fourth application scenario, we highlight how winter rain events can be detected in SAR time series, revealing important information about the area extent of internal accumulation. In the last application scenario, averaged summer SAR images were found to have potential in assisting the process of mapping glaciers outlines, especially in the presence of seasonal snow. Altogether we present examples of how to map glaciers and to further understand glaciological processes using the existing and future massive amount of multi-sensor time series data.

Description: Using SAR satellite data time series for regional glacier mapping Solveig H. Winsvold, Andreas Kääb, Christopher Nuth, Liss M. Andreassen, Ward J. J. van Pelt, and Thomas Schellenberger The Cryosphere, 12, 867-890, https://doi.org/10.5194/tc-12-867-2018, 2018 With dense SAR satellite data time series it is possible to map surface and subsurface glacier properties that vary in time. On Sentinel-1A and RADARSAT-2 backscatter time series images over mainland Norway and Svalbard, we outline how to map glaciers using descriptive methods. We present five application scenarios. The first shows potential for tracking transient snow lines with SAR backscatter time series and correlates with both optical satellite images (Sentinel-2A and Landsat 8) and equilibrium line altitudes derived from in situ surface mass balance data. In the second application scenario, time series representation of glacier facies corresponding to SAR glacier zones shows potential for a more accurate delineation of the zones and how they change in time. The third application scenario investigates the firn evolution using dense SAR backscatter time series together with a coupled energy balance and multilayer firn model. We find strong correlation between backscatter signals with both the modeled firn air content and modeled wetness in the firn. In the fourth application scenario, we highlight how winter rain events can be detected in SAR time series, revealing important information about the area extent of internal accumulation. In the last application scenario, averaged summer SAR images were found to have potential in assisting the process of mapping glaciers outlines, especially in the presence of seasonal snow. Altogether we present examples of how to map glaciers and to further understand glaciological processes using the existing and future massive amount of multi-sensor time series data.

Description: A large-area blackbody for inflight calibration of an infrared interferometer deployed on board a long-duration balloon for stratospheric research Friedhelm Olschewski, Christian Monte, Albert Adibekyan, Max Reiniger, Berndt Gutschwager, Joerg Hollandt, and Ralf Koppmann Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2017-417,2018 Manuscript under review for AMT (discussion: open, 0 comments) The Institute for Atmospheric and Environmental Research at the University of Wuppertal designed and manufactured a proto-type of the large-area blackbody for inflight calibration of an infrared interferometer deployed onboard a long-duration balloon for stratospheric research.

Description: Limited angle tomography of mesoscale gravity waves by the infrared limb-sounder GLORIA Isabell Krisch, Jörn Ungermann, Peter Preusse, Erik Kretschmer, and Martin Riese Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2018-72,2018 Manuscript under review for AMT (discussion: open, 0 comments) Three-dimensional measurements of gravity waves are required, in order to quantify their direction resolved momentum fluxes and get a better understanding of their propagation characteristics. Such 3-D measurements of gravity waves in the lowermost stratosphere can be provided by the airborne Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) using full angle tomography. Closed flight patterns of sufficient size are needed to acquire the full set of angular measurements for full angle tomography. These take about two hours and are not feasible everywhere due to scientific reasons or air traffic control restrictions. Hence, this paper investigates the usability of limited angle tomography for gravity wave research. Limited angle tomography uses only a limited set of angles for tomographic reconstruction and can be applied on linear flight patterns. A synthetic end-to-end simulation has been performed to investigate the sensitivity of limited angle tomography towards gravity waves with different wavelengths and orientations in respect to the flight path. For waves with wave fronts roughly perpendicular to the flight path, limited angle tomography and full angle tomography can derive wave parameters like wavelength, amplitude and wave orientation with similar accuracy. For waves with horizontal wavelength above 200 km and vertical wavelength above 3 km, the wavelengths can be retrieved with less than 10 % error, the amplitude with less than 20 % and the horizontal wave direction with an error below 10°. This is confirmed by a comparison of results obtained from full angle tomography and limited angle tomography for a real measurement case on 25 January 2016 over Iceland. The reproduction quality of gravity wave parameters with limited angle tomography, however, depends strongly on the orientation of the waves with respect to the flight path. Thus, full angle tomography might be preferable in cases where the orientation of the wave cannot be predicted or waves with different orientations exist in the same volume and thus the flight path cannot be adjusted accordingly. Also for low amplitude waves and short scale waves full angle tomography has advantages due to its slightly higher resolution and accuracy.

Description: A simple biota removal algorithm for 35 GHz cloud radar measurements Madhu Chandra R. Kalapureddy, Patra Sukanya, Subrata K. Das, Sachin M. Deshpande, Govindan Pandithurai, Andrew L. Pazamany, Jha Ambuj K., Kaustav Chakravarty, Prasad Kalekar, Hari Krishna Devisetty, and Sreenivas Annam Atmos. Meas. Tech., 11, 1417-1436, https://doi.org/10.5194/amt-11-1417-2018, 2018 A new technique to separate cloud and non-hydrometeor returns from a cloud radar high-resolution reflectivity measurements is proposed. The TEST algorithm potentially identifies cloud height with the theoretical echo sensitivity curves and observed echo statistics for the cloud height tracing. TEST is more robust in identifying and filtering out the biota contributions by constraining further with spectral width and LDR measurements. This algorithm improves the monsoon cloud characterization.

Description: Over-calcified forms of the coccolithophore Emiliania huxleyi in high-CO 2 waters are not preadapted to ocean acidification Peter von Dassow, Francisco Díaz-Rosas, El Mahdi Bendif, Juan-Diego Gaitán-Espitia, Daniella Mella-Flores, Sebastian Rokitta, Uwe John, and Rodrigo Torres Biogeosciences, 15, 1515-1534, https://doi.org/10.5194/bg-15-1515-2018, 2018 Coccolithophores are microalgae which produce much of the calcium carbonate in the ocean, important to making organic carbon sink to great depths, and they may be negatively affected by the decline in ocean pH as CO 2 rises. Can these important microbes adapt? This study found that coccolithophores inhabiting waters naturally low in pH may have already reached the limit of their ability to adapt. This suggests that how the ocean's biota sequester carbon will be strongly affected in the future.

Description: Increasing coastal slump activity impacts the release of sediment and organic carbon into the Arctic Ocean Justine L. Ramage, Anna M. Irrgang, Anne Morgenstern, and Hugues Lantuit Biogeosciences, 15, 1483-1495, https://doi.org/10.5194/bg-15-1483-2018, 2018 We describe the evolution of thaw slumps between 1952 and 2011 along the Yukon Coast, Canada, and calculate the contribution of the slumps to the carbon budget in this area. The number of slumps has increased by 73 % over the period. These slumps displaced more than 16 billion m 3 of material and mobilized 146 t of carbon. This represents 0.6 % of the annual carbon flux released from shoreline retreat, which shows that the contribution of slumps to the nearshore carbon budget is non-negligible.

Description: A new tool for model assessment in the frequency domain – Spectral Taylor Diagram : application to a global ocean general circulation model with tides Mabel Costa Calim, Paulo Nobre, Peter Oke, Andreas Schiller, Leo San Pedro Siqueira, and Guilherme Pimenta Castelão Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-5,2018 Manuscript under review for GMD (discussion: open, 0 comments) A new tool inspired on tides is introduced. The Spectral Taylor Diagram designed for evaluating and monitoring models performance in frequency domain calculates the degree of correspondence between simulated and observed fields for a given frequency (or a band of frequencies). It's a powerful tool to detect co-oscillating patterns in multi scale analysis, without using filtering techniques.

Description: A continuum model of ice mélange and its role during retreat of the Antarctic Ice Sheet David Pollard, Robert M. DeConto, and Richard B. Alley Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-28,2018 Manuscript under review for GMD (discussion: open, 0 comments) Around the margins of ice sheets in contact with the ocean, breaking of icebergs can generate large amounts of floating ice debris called "melange". In major Greenland fjords, melange significantly slows down ice flow from upstream. Our study uses numerical models applied to past and possible future episodes of drastic Antarctic Ice Sheet retreat. We find that, unlike Greenland, the Antarctic melange does not significantly impede flow or slow ice retreat and associated sea-level rise.

Description: TOAST 1.0: Tropospheric Ozone Attribution of Sources with Tagging for CESM 1.2.2 Tim Butler, Aurelia Lupascu, Jane Coates, and Shuai Zhu Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-59,2018 Manuscript under review for GMD (discussion: open, 0 comments) This paper describes a method for determining origin of tropospheric ozone simulated in a global chemistry-climate model. This technique provides can show which precursor compounds were responsible for simulated ozone, and where they were emitted. In this paper we describe our technique, and compare and contrast it with several other similar techniques.

Description: Implementation of a comprehensive ice crystal formation parameterization for cirrus and mixed-phase clouds into the EMAC model (based on MESSy 2.53) Sara Bacer, Sylvia C. Sullivan, Vlassis A. Karydis, Donifan Barahona, Martina Krämer, Athanasios Nenes, Holger Tost, Alexandra P. Tsimpidi, Jos Lelieveld, and Andrea Pozzer Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-62,2018 Manuscript under review for GMD (discussion: open, 0 comments) The complexity of ice nucleation mechanisms and aerosol-ice interactions makes their representation still challenging in the atmospheric models. We have implemented a comprehensive ice crystal formation parameterization in the global chemistry-climate model EMAC to improve the representation of ice crystal number concentrations (ICNCs). The newly implemented parameterization, in comparison with the standard EMAC results, produces ICNCs that are closer to the observations.

Description: Modular System for Shelves and Coasts (MOSSCO v1.0) – a flexible and multi-component framework for coupled coastal ocean ecosystem modelling Carsten Lemmen, Richard Hofmeister, Knut Klingbeil, M. Hassan Nasermoaddeli, Onur Kerimoglu, Hans Burchard, Frank Kösters, and Kai W. Wirtz Geosci. Model Dev., 11, 915-935, https://doi.org/10.5194/gmd-11-915-2018, 2018 To describe coasts in a computer model, many processes have to be represented, from the air to the water to the ocean floor, from different scientific disciplines. No existing computer model adequately addresses this complexity. We present the Modular System for Shelves and Coasts (MOSSCO), which embraces this diversity and flexibly connects several tens of individual process models. MOSSCO also makes it easier to bring local knowledge to the Earth system level.

Description: A continuum model of ice mélange and its role during retreat of the Antarctic Ice Sheet David Pollard, Robert M. DeConto, and Richard B. Alley Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-28,2018 Manuscript under review for GMD (discussion: open, 0 comments) Around the margins of ice sheets in contact with the ocean, breaking of icebergs can generate large amounts of floating ice debris called "melange". In major Greenland fjords, melange significantly slows down ice flow from upstream. Our study uses numerical models applied to past and possible future episodes of drastic Antarctic Ice Sheet retreat. We find that, unlike Greenland, the Antarctic melange does not significantly impede flow or slow ice retreat and associated sea-level rise.

Description: A new tool for model assessment in the frequency domain – Spectral Taylor Diagram : application to a global ocean general circulation model with tides Mabel Costa Calim, Paulo Nobre, Peter Oke, Andreas Schiller, Leo San Pedro Siqueira, and Guilherme Pimenta Castelão Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-5,2018 Manuscript under review for GMD (discussion: open, 0 comments) A new tool inspired on tides is introduced. The Spectral Taylor Diagram designed for evaluating and monitoring models performance in frequency domain calculates the degree of correspondence between simulated and observed fields for a given frequency (or a band of frequencies). It's a powerful tool to detect co-oscillating patterns in multi scale analysis, without using filtering techniques.

Description: Modular System for Shelves and Coasts (MOSSCO v1.0) – a flexible and multi-component framework for coupled coastal ocean ecosystem modelling Carsten Lemmen, Richard Hofmeister, Knut Klingbeil, M. Hassan Nasermoaddeli, Onur Kerimoglu, Hans Burchard, Frank Kösters, and Kai W. Wirtz Geosci. Model Dev., 11, 915-935, https://doi.org/10.5194/gmd-11-915-2018, 2018 To describe coasts in a computer model, many processes have to be represented, from the air to the water to the ocean floor, from different scientific disciplines. No existing computer model adequately addresses this complexity. We present the Modular System for Shelves and Coasts (MOSSCO), which embraces this diversity and flexibly connects several tens of individual process models. MOSSCO also makes it easier to bring local knowledge to the Earth system level.

Description: Implementation of a comprehensive ice crystal formation parameterization for cirrus and mixed-phase clouds into the EMAC model (based on MESSy 2.53) Sara Bacer, Sylvia C. Sullivan, Vlassis A. Karydis, Donifan Barahona, Martina Krämer, Athanasios Nenes, Holger Tost, Alexandra P. Tsimpidi, Jos Lelieveld, and Andrea Pozzer Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-62,2018 Manuscript under review for GMD (discussion: open, 0 comments) The complexity of ice nucleation mechanisms and aerosol-ice interactions makes their representation still challenging in the atmospheric models. We have implemented a comprehensive ice crystal formation parameterization in the global chemistry-climate model EMAC to improve the representation of ice crystal number concentrations (ICNCs). The newly implemented parameterization, in comparison with the standard EMAC results, produces ICNCs that are closer to the observations.

Description: TOAST 1.0: Tropospheric Ozone Attribution of Sources with Tagging for CESM 1.2.2 Tim Butler, Aurelia Lupascu, Jane Coates, and Shuai Zhu Geosci. Model Dev. Discuss., https//doi.org/10.5194/gmd-2018-59,2018 Manuscript under review for GMD (discussion: open, 0 comments) This paper describes a method for determining origin of tropospheric ozone simulated in a global chemistry-climate model. This technique provides can show which precursor compounds were responsible for simulated ozone, and where they were emitted. In this paper we describe our technique, and compare and contrast it with several other similar techniques.

Description: Regional scaling of annual mean precipitation and water availability with global temperature change Peter Greve, Lukas Gudmundsson, and Sonia I. Seneviratne Earth Syst. Dynam., 9, 227-240, https://doi.org/10.5194/esd-9-227-2018, 2018 Assessing projected hydroclimatological changes is crucial, but associated with large uncertainties. We statistically assess here the response of precipitation and water availability to global temperature change, enabling us to estimate the significance of drying/wetting tendencies under anthropogenic climate change. We further show that opting for a 1.5 K warming target just slightly influences the mean response but could substantially reduce the risk of experiencing extreme changes.

Description: Thermodynamics of saline and fresh water mixing in estuaries Zhilin Zhang and Hubert H. G. Savenije Earth Syst. Dynam., 9, 241-247, https://doi.org/10.5194/esd-9-241-2018, 2018 This paper presents a new equation for the dispersion of salinity in alluvial estuaries based on the maximum power concept. The new equation is physically based and replaces previous empirical equations. It is very useful for application in practice because in contrast to previous methods it no longer requires a calibration parameter, turning the method into a predictive method. The paper presents successful applications in more than 23 estuaries in different parts of the world.

Description: Using Network Theory and Machine Learning to predict El Niño Peter D. Nooteboom, Qing Yi Feng, Cristóbal López, Emilio Hernández-García, and Henk A. Dijkstra Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-13,2018 Manuscript under review for ESD (discussion: open, 0 comments) The prediction of the El Niño phenomenon, an increased sea surface temperature in the eastern Pacific, fascinates people for a long time. El Niño is associated with natural disasters, such as droughts and floods. Current methods can make a reliable prediction of this phenomenon up to six months ahead. However, this article presents a method which combines network theory and machine learning and predicts El Niño up to one year ahead.

Description: Altimetry, gravimetry, GPS and viscoelastic modeling data for the joint inversion for glacial isostatic adjustment in Antarctica (ESA STSE Project REGINA) Ingo Sasgen, Alba Martín-Español, Alexander Horvath, Volker Klemann, Elizabeth J. Petrie, Bert Wouters, Martin Horwath, Roland Pail, Jonathan L. Bamber, Peter J. Clarke, Hannes Konrad, Terry Wilson, and Mark R. Drinkwater Earth Syst. Sci. Data, 10, 493-523, https://doi.org/10.5194/essd-10-493-2018, 2018 We present a collection of data sets, consisting of surface-elevation rates for Antarctic ice sheet from a combination of Envisat and ICESat, bedrock uplift rates for 118 GPS sites in Antarctica, and optimally filtered GRACE gravity field rates. We provide viscoelastic response functions to a disc load forcing for Earth structures present in East and West Antarctica. This data collection enables a joint inversion for present-day ice-mass changes and glacial isostatic adjustment in Antarctica.

Description: The Probability Distribution of Daily Precipitation at the Point and Catchment Scales in the United States Lei Ye, Lars S. Hanson, Pengqi Ding, Dingbao Wang, and Richard M. Vogel Hydrol. Earth Syst. Sci. Discuss., https//doi.org/10.5194/hess-2018-85,2018 Manuscript under review for HESS (discussion: open, 0 comments) Choosing a probability distribution to represent daily precipitation depths is important for precipitation frequency analysis, stochastic precipitation modeling and in climate trend assessments. Early studies identified the 2-parameter Gamma (G2) distribution as a suitable distribution for wet-day precipitation based on traditional goodness of fit tests. Here, probability plot correlation coefficients and L-moment diagrams are used to examine distributional alternatives for the full-record and wet-day series of daily precipitation at the point and catchment scales in the United States. Importantly, the G2 distribution performs poorly in comparison to either the Pearson Type-III (P3) or Kappa (KAP) distributions. The analysis indicates that the P3 distribution fits the full record of daily precipitation at both the point and catchment scales remarkably well; while the KAP distribution best describes the distribution of wet-day precipitation at the point scale, and the performance of KAP and P3 distributions is comparable for wet-day precipitation at the catchment scale.

Description: Multiple causes of nonstationarity in the Weihe annual low-flow series Bin Xiong, Lihua Xiong, Jie Chen, Chong-Yu Xu, and Lingqi Li Hydrol. Earth Syst. Sci., 22, 1525-1542, https://doi.org/10.5194/hess-22-1525-2018, 2018 In changing environments, extreme low-flow events are expected to increase. Frequency analysis of low-flow events considering the impacts of changing environments has attracted increasing attention. This study developed a frequency analysis framework by applying 11 indices to trace the main causes of the change in the annual extreme low-flow events of the Weihe River. We showed that the fluctuation in annual low-flow series was affected by climate, streamflow recession and irrigation area.

Description: Calibrating electromagnetic induction conductivities with time-domain reflectometry measurements Giovanna Dragonetti, Alessandro Comegna, Ali Ajeel, Gian Piero Deidda, Nicola Lamaddalena, Giuseppe Rodriguez, Giulio Vignoli, and Antonio Coppola Hydrol. Earth Syst. Sci., 22, 1509-1523, https://doi.org/10.5194/hess-22-1509-2018, 2018 The paper aims to infer the bulk electrical conductivity distribution in the root zone from EMI readings. TDR measurements were used as ground-truth data to evaluate the goodness of the estimations by EMI inversion. The approach is based on the mean and standard deviation of the EMI and TDR series. It looks for the physical reasons for the differences between EMI- and TDR-based electrical conductivity and provides a correction of the bias based on the statistical sources of the discrepancies.