WILBERT

Description: Design of a carrier-depletion Mach-Zehnder modulator in 250 nm silicon-on-insulator technology María Félix Rosa, Lotte Rathgeber, Raik Elster, Niklas Hoppe, Thomas Föhn, Martin Schmidt, Wolfgang Vogel, and Manfred Berroth Adv. Radio Sci., 15, 269-281, https://doi.org/10.5194/ars-15-269-2017, 2017 We present the design of an optical modulator for amplitude modulation in a special silicon-on-insulator technology with 250 nm silicon layer thickness. The design of the modulator is optimized by simulating different parameters like dimension of the structure and doping of the silicon to improve the performance of the device. In addition, a prototype is fabricated and successfully measured to demonstrate the functionality of the technology.

Description: Comparison of non-convex cost functionals for the consideration of phase differences in phaseless near-field far-field transformations of measured antenna fields Josef Knapp, Alexander Paulus, Carlos Lopez, and Thomas F. Eibert Adv. Radio Sci., 15, 11-19, https://doi.org/10.5194/ars-15-11-2017, 2017 This work introduces two methods which extend the non-convex minimization problem arising in phaseless (NF) far-field (FF) transformations. With the new extensions, knowledge about phase differences between measurement points can be incorporated into the minimization problem. The additional information helps to avoid stationary points of the minimization cost functional which would otherwise compromise the result of the near-field far-field transformation. The methods are incorporated into the Fast Irregular Antenna Field Transformation Algorithm (FIAFTA), analyzed and compared. Their effectiveness is shown by transforming synthetic near-field data sets with partial knowledge of phase differences to the far-field.

Description: Differential form representation of stochastic electromagnetic fields Michael Haider and Johannes A. Russer Adv. Radio Sci., 15, 21-28, https://doi.org/10.5194/ars-15-21-2017, 2017 In this work, we revisit the theory of stochastic electromagnetic fields using exterior differential forms. We present a short overview as well as a brief introduction to the application of differential forms in electromagnetic theory. Within the framework of exterior calculus we derive equations for the second order moments, describing stochastic electromagnetic fields. Since the resulting objects are continuous quantities in space, a discretization scheme based on the Method of Moments (MoM) is introduced for numerical treatment. The MoM is applied in such a way, that the notation of exterior calculus is maintained while we still arrive at the same set of algebraic equations as obtained for the case of formulating the theory using the traditional notation of vector calculus. We conclude with an analytic calculation of the radiated electric field of two Hertzian dipole, excited by uncorrelated random currents.

Description: Physical optics and full-wave simulations of transmission of electromagnetic fields through electrically large planar meta-sheets Ezgi Öziş, Andrey V. Osipov, and Thomas F. Eibert Adv. Radio Sci., 15, 29-35, https://doi.org/10.5194/ars-15-29-2017, 2017 Meta-sheets open up new opportunities in the design of radomes for microwave antennas. A meta-sheet typically consists of a periodic array of small resonators embedded in a thin dielectric layer. The smallness of unit cells and the large electrical size of microwave radomes significantly complicate full-wave numerical simulations as a very fine sampling over a large area is required. This paper proposes an efficient simulation approach, which combines Physical Optics and Finite Element methods.

Description: Discretization analysis of bifurcation based nonlinear amplifiers Sven Feldkord, Marco Reit, and Wolfgang Mathis Adv. Radio Sci., 15, 43-47, https://doi.org/10.5194/ars-15-43-2017, 2017 Recently, for modeling biological amplification processes, nonlinear amplifiers based on the Andronov–Hopf bifurcation have become a focus of attention. In this contribution, we analyze discrete-time implementations of this type of amplifiers. The effects of the time-discretization by explicit integration methods are discussed. A novel discrete-time system based on the Neimark–Sacker bifurcation is introduced, that outstandingly approximates the behavior of a particular Hopf-type amplifier.

Description: Advanced design and characterization methodologies for memory-aware CMOS power-amplifier implementation Martin Schleyer, Dominic Maurath, Heinrich Klar, and Friedel Gerfers Adv. Radio Sci., 15, 49-54, https://doi.org/10.5194/ars-15-49-2017, 2017 This paper reports on an effective root-cause analysis method of memory effects in power amplifiers, as well as introduces compensation techniques on a circuit design level. Despite conventional memory-effect approaches, the discussed method uses a two-tone scan over a wide operation and modulation range. The approach is demonstrated on a 65-nm CMOS power amplifier with an OIP1 of 27 dBm and a PAE of over 30 % using WCDMA and LTE signals.

Description: Behavioral modeling of nonlinear transfer systems with load-dependent X -parameters Seyed Mohammadamin Moosavi, Christian Widemann, and Wolfgang Mathis Adv. Radio Sci., 15, 37-41, https://doi.org/10.5194/ars-15-37-2017, 2017 In this contribution, different approaches based on the X -parameters TM to model the behavior of mismatched nonlinear transfer systems are examined. The X -parameters based on the PHD 1 -principle introduced by Verspecht and Root (2006) as an extension of the well-known S -parameters describe nonlinear microwave 2-port-networks under large signal conditions. Using load-pull measurement techniques they can be used for arbitrary load situations. Beside this load-pull approach, in the work of Cai et al. (2015), it is stated that it is sufficient to use one optimized X -parameter set for each value of the load reflection coefficient without introducing a large error. In another contribution of Cai and Yu (2015), this approach is extended to cover the whole smith chart with one optimized X -parameter set instead. In this work, these different approaches are compared and brought into question. 1 polyharmonic distortion; Verspecht and Root (2006).

Description: Electrostatic sensor modeling for torque measurements Michał Mika, Mirjam Dannert, Felix Mett, Harry Weber, Wolfgang Mathis, and Udo Nackenhorst Adv. Radio Sci., 15, 55-60, https://doi.org/10.5194/ars-15-55-2017, 2017 Torque load measurements play an important part in various engineering applications, as for automotive industry, in which the drive torque of a motor has to be determined. A widely used measuring method are strain gauges. A thin flexible foil, which supports a metallic pattern, is glued to the surface of the object the torque is being applied to. In case of a deformation due to the torque load, the change in the electrical resistance is measured. With the combination of constitutive equations the applied torque load is determined by the change of electrical resistance. The creep of the glue and the foil material, together with the temperature and humidity dependence, may become an obstacle for some applications Kapralov and Fesenko (1984). Thus, there have been optical and magnetical, as well as capacitive sensors introduced). This paper discusses the general idea behind an electrostatic capacitive sensor based on a simple draft of an exemplary measurement setup. For better understanding an own electrostatical, geometrical and mechanical model of this setup has been developed.

Description: Sparse representation discretization errors in multi-sensor radar target motion estimation Hossein Azodi, Uwe Siart, and Thomas F. Eibert Adv. Radio Sci., 15, 69-76, https://doi.org/10.5194/ars-15-69-2017, 2017 This work investigates the errors, numerically and analytically, which occur due to the discretization of surveillance space in a multi-sensor radar system. The result of these investigations help to imprve the efficiency of the well-known compressed sensing algorithms. The improvement is critical for the cases where the signal processing algorithms must deliver the results within very short time intervals, e.g. 5 milliseconds or less.

Description: A Novel Target-Height Estimation Approach Using Radar-Wave Multipath Propagation for Automotive Applications Amir Laribi, Markus Hahn, Jürgen Dickmann, and Christian Waldschmidt Adv. Radio Sci., 15, 61-67, https://doi.org/10.5194/ars-15-61-2017, 2017 This paper introduces a novel target height estimation approach using a Frequency Modulation Continuous Wave (FMCW) automotive radar. The presented algorithm takes advantage of radar wave multipath propagation to measure the height of objects in the vehicle surroundings. A multipath propagation model is presented first, then a target height is formulated using geometry, based on the presented propagation model. It is then shown from Sensor-Target geometry that height estimation of targets is highly dependent on the radar range resolution, target range and target height. The high resolution algorithm RELAX is discussed and applied to collected raw data to enhance the radar range resolution capability. This enables a more accurate height estimation especially for low targets. Finally, the results of a measurement campaign using corner reflectors at different heights are discussed to show that target heights can be very accurately resolved by the proposed algorithm and that for low targets an average mean height estimation error of 0.03 m has been achieved by the proposed height finding algorithm.

Description: Novel post-Doppler STAP with a priori knowledge information for traffic monitoring applications: basic idea and first results André B. C. da Silva and Stefan V. Baumgartner Adv. Radio Sci., 15, 77-82, https://doi.org/10.5194/ars-15-77-2017, 2017 This paper presents a novel algorithm for traffic monitoring applications, where the powerful post-Doppler space-time adaptive processing (PD STAP) is combined with the OpenStreetMap database. The road map is applied after the PD STAP for recognizing and rejecting false detections, and for repositioning off-road vehicles. The algorithm was tested using real multi-channel data acquired by DLR’s airborne F-SAR. The experimental results are shown and discussed, and the novelties are highlighted.

Description: Lithium-ion battery models: a comparative study and a model-based powerline communication Fida Saidani, Franz X. Hutter, Rares-George Scurtu, Wolfgang Braunwarth, and Joachim N. Burghartz Adv. Radio Sci., 15, 83-91, https://doi.org/10.5194/ars-15-83-2017, 2017 This paper presents a comparative overview of models for lithium-ion batteries from an electrical Engineering Point of view. The comparison criteria and the different models are presented. After this comparison, a model is used to establish a new communication concept.

Description: State of charge classification for lithium-ion batteries using impedance based features Marian Patrik Felder and Jürgen Götze Adv. Radio Sci., 15, 93-97, https://doi.org/10.5194/ars-15-93-2017, 2017 Currently, the electrification of the drive train of passenger cars takes place, and the task of obtaining precise knowledge about the condition of the on board batteries gains importance. Due to internal characteristics, several existing methods cannot be used. This work describes an impedance based approach using the Taylor Fourier transformation. The parameters extracted by the method can be used as features in machine learning algorithms.

Description: Orthogonal frequency division multiplexing with amplitude shift keying subcarrier modulation as a reliable and efficient transmission scheme for self-mixing receivers Jonas Kornprobst, Thomas J. Mittermaier, and Thomas F. Eibert Adv. Radio Sci., 15, 99-106, https://doi.org/10.5194/ars-15-99-2017, 2017 By analyzing the behavior of a self-mixing receiver, an appropriate model with a squre-law device can be obtained. This model is analyzed and a novel transmission technique with higher spectral efficiency is deduced by the formulation of the signal reconstruction problem as a phase retrival problem. Simulation results show the good performance of the proposed method.

Description: An interoperable research data infrastructure to support climate service development Tiziana De Filippis, Leandro Rocchi, and Elena Rapisardi Adv. Sci. Res., 14, 335-340, https://doi.org/10.5194/asr-14-335-2018, 2018 Accessibility, availability, re-use and re-distribution of scientific data are prerequisites to build climate services across Europe. The proposed architecture uses open-source tools and interoperable standards to ensure sustainability in the development and deployment of Web applications. The availability of structured raw data as customized information paves the way for building climate service purveyors to support adaptation, mitigation and risk management at different scales.

Description: Civil protection and Damaging Hydrogeological Events: comparative analysis of the 2000 and 2015 events in Calabria (southern Italy) Olga Petrucci, Tommaso Caloiero, Angela Aurora Pasqua, Piero Perrotta, Luigi Russo, and Carlo Tansi Adv. Geosci., 44, 101-113, https://doi.org/10.5194/adgeo-44-101-2017, 2017 This work presents a methodological approach to perform the comparative analysis of 2 events affecting the Calabria region (southern Italy), by collecting all the qualitative and quantitative features useful to describe both rain and damage. The first event occurred between 8 and 10 September 2000 while the second event occurred between 30 October and 1 November 2015. We concluded that, in the 2015 event, the management of pre-event phases allowed to reduce the number of victims.

Description: An evaluation of the potential of Sentinel 1 for improving flash flood predictions via soil moisture–data assimilation Luca Cenci, Luca Pulvirenti, Giorgio Boni, Marco Chini, Patrick Matgen, Simone Gabellani, Giuseppe Squicciarino, and Nazzareno Pierdicca Adv. Geosci., 44, 89-100, https://doi.org/10.5194/adgeo-44-89-2017, 2017 This research aims at improving hydrological modelling skills of flash flood prediction by exploiting earth observation data. To this aim, high spatial/moderate temporal resolution soil moisture maps, derived from Sentinel 1 acquisitions, were used in a data assimilation framework. Findings revealed the potential of Sentinel 1-based soil moisture data assimilation for flash flood risk reduction and improved our understanding of the capabilities of the aforementioned satellite-derived product.

Description: Flood and landslide warning based on rainfall thresholds and soil moisture indexes: the HEWS (Hydrohazards Early Warning System) for Sicily Giuseppina Brigandì, Giuseppe Tito Aronica, Brunella Bonaccorso, Roberto Gueli, and Giuseppe Basile Adv. Geosci., 44, 79-88, https://doi.org/10.5194/adgeo-44-79-2017, 2017 The paper presents the flood and landslide early warning system HEWS developed by the University of Messina for the Integrated Multi-Risk Decentralised Functional Centre of Sicily (Italy). HEWS implements a methodology based on the combined use of rainfall thresholds, soil moisture modelling and quantitative precipitation forecast (QPF) to issue alert bulletins both for floods and landslide. The software Delft-FEWS has been adopted as operation platform to support the implementation of HEWS.

Description: Seasonal range test run with Global Eta Framework Dragan Latinović, Sin Chan Chou, and Miodrag Rančić Adv. Sci. Res., 14, 247-251, https://doi.org/10.5194/asr-14-247-2017, 2017 Global Eta Framework (GEF) is run on a cubed-sphere grid topology. A nonhydrostatic version of this atmospheric model is under development at CPTEC, SP, Brazil. This note describes preliminary tests with the GEF in which model performance is evaluated in seasonal simulations at a horizontal resolution of 25 km, running in the hydrostatic mode. Comparison of these simulations with the ERA-Interim reanalyses shows the model is able to well capture the main seasonal climate characteristics.

Description: An initial ULF wave index derived from 2 years of Swarm observations Constantinos Papadimitriou, Georgios Balasis, Ioannis A. Daglis, and Omiros Giannakis Ann. Geophys., 36, 287-299, https://doi.org/10.5194/angeo-36-287-2018, 2018 Swarm is the fourth Earth Explorer mission of the European Space Agency (ESA), launched on 23 November 2013. The mission provides an opportunity for better knowledge of the near-Earth electromagnetic environment. This study presents an initial attempt to derive an ultra low-frequency (ULF) wave index from low-Earth orbit satellite data. The technique can be potentially used to define a new product from the mission, the Swarm ULF wave index, which would be suitable for space weather applications.

Description: Mesopause region temperature variability and its trend in southern Brazil Mateus S. Venturini, José V. Bageston, Nattan R. Caetano, Lucas V. Peres, Hassan Bencherif, and Nelson J. Schuch Ann. Geophys., 36, 301-310, https://doi.org/10.5194/angeo-36-301-2018, 2018 In the past years, the study of the temperature trend and its variability in the upper atmosphere has increased. However, most works were conducted in regions of medium and high latitude. Therefore, we aim to analyze a low-latitude region, the south of Brazil and surrounding areas. Using data from the TIMED/SABER instrument and applying the Trend-Run model for temperature trend analyses, no substantial temperature trend was found in the MLT region (80–100 km) from the years 2003 to 2014.

Description: Case study of mesospheric front dissipation observed over the northeast of Brazil Amauri Fragoso Medeiros, Igo Paulino, Cristiano Max Wrasse, Joaquim Fechine, Hisao Takahashi, José Valentin Bageston, Ana Roberta Paulino, and Ricardo Arlen Buriti Ann. Geophys., 36, 311-319, https://doi.org/10.5194/angeo-36-311-2018, 2018 On 3 October 2005, a mesospheric front was observed over São João do Cariri (7.4° S, 36.5° W) propagating to the northeast in the OH airglow images. One and a half hours later, it disappeared completely and ripples were observed in the eastern part of the images. After studying the background atmosphere, the main conclusion of this work was that the instability in the airglow layer did not allow the propagation of the front to the other side of the local zenith.

Description: Latitudinal variation rate of geomagnetic cutoff rigidity in the active Chilean convergent margin Enrique G. Cordaro, Patricio Venegas, and David Laroze Ann. Geophys., 36, 275-285, https://doi.org/10.5194/angeo-36-275-2018, 2018 The interaction between the magnetic field and the particles coming from outer space, which apparently have a relationship with tectonic plates, is studied. The major earthquakes of Maule (2010, 8.8  M w ), Sumatra (2004, 9.2  M w ) and Tohoku (2011, 9.0  M w ) were studied, similar frequencies being found in the vertical component of the magnetic field (microhertz range). The temporal evolution of the magnetic oscillations showed the possible link with the seismic movement of Maule in 2010.

Description: Intrinsic parameters of periodic waves observed in the OI6300 airglow layer over the Brazilian equatorial region Igo Paulino, Joyrles F. Moraes, Gleuson L. Maranhão, Cristiano M. Wrasse, Ricardo Arlen Buriti, Amauri F. Medeiros, Ana Roberta Paulino, Hisao Takahashi, Jonathan J. Makela, John W. Meriwether, and José André V. Campos Ann. Geophys., 36, 265-273, https://doi.org/10.5194/angeo-36-265-2018, 2018 This article presents characteristics of periodic waves observed in the thermosphere from airglow images collected in the Northeast of Brazil. Using simultaneous measurements of the background wind in the airglow emission altitudes, it was possible to estimate the intrinsic parameters and the role of the wind in the propagation of the waves into the thermosphere. An anisotropy in the propagation direction of the waves was observed and it could be explained by the wind filtering process.

Description: Modelling biogeochemical processes in sediments from the north-western Adriatic Sea: response to enhanced particulate organic carbon fluxes Daniele Brigolin, Christophe Rabouille, Bruno Bombled, Silvia Colla, Salvatrice Vizzini, Roberto Pastres, and Fabio Pranovi Biogeosciences, 15, 1347-1366, https://doi.org/10.5194/bg-15-1347-2018, 2018 We present the result of a study carried out in the north-western Adriatic Sea by combining two different types of models with field sampling. A mussel farm was taken as a local source of perturbation to the natural flux of particulate organic carbon to the sediment. Differences in fluxes were primarily associated with mussel physiological conditions. Although restricted, these changes in particulate organic carbon fluxes induced visible effects on sediment biogeochemistry.

Description: The pyrogeography of eastern boreal Canada from 1901 to 2012 simulated with the LPJ-LMfire model Emeline Chaste, Martin P. Girardin, Jed O. Kaplan, Jeanne Portier, Yves Bergeron, and Christelle Hély Biogeosciences, 15, 1273-1292, https://doi.org/10.5194/bg-15-1273-2018, 2018 A vegetation model was used to reconstruct fire activity from 1901 to 2012 in relation to changes in lightning ignition, climate, and vegetation in eastern Canada's boreal forest. The model correctly simulated the history of fire activity. The results showed that fire activity is ignition limited but is also greatly affected by both climate and vegetation. This research aims to develop a vegetation model that could be used to predict the future impacts of climate changes on fire activity.

Description: Towards an assessment of riverine dissolved organic carbon in surface waters of the western Arctic Ocean based on remote sensing and biogeochemical modeling Vincent Le Fouest, Atsushi Matsuoka, Manfredi Manizza, Mona Shernetsky, Bruno Tremblay, and Marcel Babin Biogeosciences, 15, 1335-1346, https://doi.org/10.5194/bg-15-1335-2018, 2018 Climate warming could enhance the load of terrigenous dissolved organic carbon (tDOC) of Arctic rivers. We show that tDOC concentrations simulated by an ocean–biogeochemical model in the Canadian Beaufort Sea compare favorably with their satellite counterparts. Over spring–summer, riverine tDOC contributes to 35 % of primary production and an equivalent of ~ 10 % of tDOC is exported westwards with the potential for fueling the biological production of the eastern Alaskan nearshore waters.

Description: Impacts of droughts and extreme-temperature events on gross primary production and ecosystem respiration: a systematic assessment across ecosystems and climate zones Jannis von Buttlar, Jakob Zscheischler, Anja Rammig, Sebastian Sippel, Markus Reichstein, Alexander Knohl, Martin Jung, Olaf Menzer, M. Altaf Arain, Nina Buchmann, Alessandro Cescatti, Damiano Gianelle, Gerard Kiely, Beverly E. Law, Vincenzo Magliulo, Hank Margolis, Harry McCaughey, Lutz Merbold, Mirco Migliavacca, Leonardo Montagnani, Walter Oechel, Marian Pavelka, Matthias Peichl, Serge Rambal, Antonio Raschi, Russell L. Scott, Francesco P. Vaccari, Eva van Gorsel, Andrej Varlagin, Georg Wohlfahrt, and Miguel D. Mahecha Biogeosciences, 15, 1293-1318, https://doi.org/10.5194/bg-15-1293-2018, 2018 Our work systematically quantifies extreme heat and drought event impacts on gross primary productivity (GPP) and ecosystem respiration globally across a wide range of ecosystems. We show that heat extremes typically increased mainly respiration whereas drought decreased both fluxes. Combined heat and drought extremes had opposing effects offsetting each other for respiration, but there were also strong reductions in GPP and hence the strongest reductions in the ecosystems carbon sink capacity.

Description: Plant responses to volcanically-elevated CO 2 in two Costa Rican forests Robert R. Bogue, Florian M. Schwandner, Joshua B. Fisher, Ryan Pavlick, Troy S. Magney, Caroline A. Famiglietti, Kerry Cawse-Nicholson, Vineet Yadav, Justin P. Linick, Gretchen B. North, and Eliecer Duarte Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-100,2018 Manuscript under review for BG (discussion: open, 0 comments) We studied trees growing on the outer areas of two volcanoes in Costa Rica to examine the effects of volcanic CO 2 emissions on tree characteristics. We measured two tree species and found that they were comprised of carbon from the volcanic CO 2 . Volcanic CO 2 emissions may also have measurable impacts on leaf function measurements. Our results have implications for reconstructing volcanic degassing histories at previously unmonitored volcanoes and studying biological impacts of elevated CO 2 .

Description: A niche comparison of Emiliania huxleyi and Gephyrocapsa oceanica and potential effects of climate change Natasha A. Gafar and Kai G. Schulz Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-88,2018 Manuscript under review for BG (discussion: open, 1 comment) Emiliania huxleyi and Gephyrocapsa oceanica are the most prolific calcifying phytoplankton in todays oceans. Here we compare their sensitivity to combined anthropogenic stressors of temperature, light and CO 2 . For the future we project a niche contraction for G. oceanica . Furthermore, there was good correlation of our new metric, the CaCO 3 production potential, with satellite derived concentrations in the modern ocean, indicating means of assessing overall coccolithophorid success in the future.

Description: Periodicity in the BrO∕SO 2 molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015 Florian Dinger, Nicole Bobrowski, Simon Warnach, Stefan Bredemeyer, Silvana Hidalgo, Santiago Arellano, Bo Galle, Ulrich Platt, and Thomas Wagner Solid Earth, 9, 247-266, https://doi.org/10.5194/se-9-247-2018, 2018 We monitored the bromine monoxide-to-sulfur dioxide molar ratio in the effusive gas plume of Cotopaxi volcano in order to gain insight into the geological processes which control the pressure regime of the volcanic system. We observed a conspicuous periodic pattern with a periodicity of about 2 weeks, which significantly correlates with the Earth tidal forcing. Our results support a possible Earth tidal impact on volcanic activity, in particular for the Cotopaxi eruption 2015.

Description: Dissolved and particulate organic carbon in Icelandic proglacial streams Peter Chifflard, Christina Fasching, Martin Reiss, and Lukas Ditzel The Cryosphere Discuss., https//doi.org/10.5194/tc-2018-32,2018 Manuscript under review for TC (discussion: open, 0 comments) For the first time, the concentration of dissolved and particulate organic carbon, as well as its optical properties in proglacial streams of Iceland, location of Europe’s largest nonpolar ice cap, was analyzed. Compared to the global annual release of 1.97 Tg C yr −1 POC, the estimation of annual release of 0.008 Tg C yr −1 (DOC) and 1.72 Tg C yr −1 (POC) from Icelandic glaciers underline the necessity to include the Icelandic glaciers in global organic carbon budget, which has not yet been done.

Description: Carbonaceous material export from Siberian permafrost tracked across the Arctic Shelf using Raman spectroscopy Robert B. Sparkes, Melissa Maher, Jerome Blewett, Ayca Dogrul Selver, Örjan Gustafsson, Igor P. Semiletov, and Bart E. van Dongen The Cryosphere Discuss., https//doi.org/10.5194/tc-2018-16,2018 Manuscript under review for TC (discussion: open, 0 comments) Ongoing climate change in the Siberian Arctic region has the potential to release large amounts of carbon, currently stored in permafrost, to the Arctic Shelf. Degradation can release this to the atmosphere as greenhouse gases. We used Raman spectroscopy to analyse a fraction of this carbon, carbonaceous material, a group that includes coal, lignite, and graphite. We were able to trace this carbon from the river mouths and coastal erosion sites across the Arctic shelf for hundreds of kilometres.

Description: A new methodology to identify minimum strain anatomical lines based on 3-D digital image correlation Jorge Barrios-Muriel, Francisco Javier Alonso Sánchez, David Rodríguez Salgado, and Francisco Romero-Sánchez Mech. Sci., 8, 337-347, https://doi.org/10.5194/ms-8-337-2017, 2017 The design of these devices involves the human body as a support environment. Based on this premise, the development of wearable devices requires an improved understanding of the skin strain field of the body segment during human motion. This paper presents a new methodology to improve and optimize the design of wearable devices, specifically orthoses, based on the combination of biomechanical studies, computer aided design/computer aided engineering (CAD/CAE) tools and 3D printing technology.

Description: Toward force detection of a cable-driven micromanipulator for a surgical robot based on disturbance observer Wenjie Wang, Lingtao Yu, and Jing Yang Mech. Sci., 8, 323-335, https://doi.org/10.5194/ms-8-323-2017, 2017 Force sensing plays an important role in minimally invasive surgery. In this study, a new asymmetric cable-driven type of micromanipulator for a surgical robot was designed, and a joint angle estimator(JAE) was designed based on the dynamical model system. Closed-loop control of the joint angle was carried out by regarding the JAE output as the feedback signal. An external force estimator was designed using a disturbance observer. The experimental results shown the correctness and validity.

Description: Impacts of bromine and iodine chemistry on tropospheric OH and HO 2 : comparing observations with box and global model perspectives Daniel Stone, Tomás Sherwen, Mathew J. Evans, Stewart Vaughan, Trevor Ingham, Lisa K. Whalley, Peter M. Edwards, Katie A. Read, James D. Lee, Sarah J. Moller, Lucy J. Carpenter, Alastair C. Lewis, and Dwayne E. Heard Atmos. Chem. Phys., 18, 3541-3561, https://doi.org/10.5194/acp-18-3541-2018, 2018 Halogen chemistry in the troposphere impacts oxidising capacity, but model studies assessing the nature of these impacts can vary according to the model framework used. In this work we present simulations of OH and HO 2 radicals using both box and global model frameworks, and compare to observations made at the Cape Verde Atmospheric Observatory. We highlight, and rationalise, differences between the model frameworks.

Description: Transport of Asian trace gases via eddy shedding from the Asian summer monsoon anticyclone and associated impacts on ozone heating rates Suvarna Fadnavis, Chaitri Roy, Rajib Chattopadhyay, Christopher E. Sioris, Alexandru Rap, Rolf Müller, K. Ravi Kumar, and Raghavan Krishnan Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-168,2018 Manuscript under review for ACP (discussion: open, 0 comments) Rapid industrialization, traffic growth, and urbanization resulted in significant increases in the tropospheric trace gases over Asia. There is global concern about rising levels of these trace gases. The monsoon convection transports these gases to the upper-level-anticyclone. In this study, we show transport of these gases to the extra-tropics via eddy-shedding from the anticyclone. We also deliberate on changes in ozone heating rates due to the transport of Asian trace gases.

Description: Ice-nucleating particle concentrations unaffected by urban air pollution in Beijing, China Jie Chen, Zhijun Wu, Stefanie Augustin-Bauditz, Sarah Grawe, Markus Hartmann, Xiangyu Pei, Zirui Liu, Dongsheng Ji, and Heike Wex Atmos. Chem. Phys., 18, 3523-3539, https://doi.org/10.5194/acp-18-3523-2018, 2018 The ice nucleation activity of urban aerosols in the atmosphere of Beijing was detected in this study. Results showed that ice-nucleating particle (INP) concentrations were not influenced by the highly variable numbers of atmospheric particles, both in mass and particle number concentrations, implying that INP concentrations might not be influenced directly by anthropogenic activities, at least not down to roughly −25 °C and maybe even below.

Description: Transport of Asian trace gases via eddy shedding from the Asian summer monsoon anticyclone and associated impacts on ozone heating rates Suvarna Fadnavis, Chaitri Roy, Rajib Chattopadhyay, Christopher E. Sioris, Alexandru Rap, Rolf Müller, K. Ravi Kumar, and Raghavan Krishnan Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-168,2018 Manuscript under review for ACP (discussion: open, 0 comments) Rapid industrialization, traffic growth, and urbanization resulted in significant increases in the tropospheric trace gases over Asia. There is global concern about rising levels of these trace gases. The monsoon convection transports these gases to the upper-level-anticyclone. In this study, we show transport of these gases to the extra-tropics via eddy-shedding from the anticyclone. We also deliberate on changes in ozone heating rates due to the transport of Asian trace gases.

Description: Characteristics of vertical velocities estimated from drop size and fall velocity spectra of a Parsivel disdrometer Dong-Kyun Kim and Chang-Keun Song Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2018-63,2018 Manuscript under review for AMT (discussion: open, 0 comments) A new techonique to estimte vertical velocties from partivel measured drop and velocity spectra is developed and the vertical velocities (w) were compared with w-component of winds measured from the anemometer at the same site. They showed quite good agreement each other, suggesting that this technique is quite reliable and applicable to rainfall studies. With these w values, rainfall characteristics related to up/downdraft was investigated in the windward and leeward side of a mountain.

Description: Light-absorption of dust and elemental carbon in snow in the Indian Himalayas and the Finnish Arctic Jonas Svensson, Johan Ström, Niku Kivekäs, Nathaniel B. Dkhar, Shresth Tayal, Ved P. Sharma, Arttu Jutila, John Backman, Aki Virkkula, Meri Ruppel, Antti Hyvärinen, Anna Kontu, Henna-Reetta Hannula, Matti Leppäranta, Rakesh K. Hooda, Atte Korhola, Eija Asmi, and Heikki Lihavainen Atmos. Meas. Tech., 11, 1403-1416, https://doi.org/10.5194/amt-11-1403-2018, 2018 Receding glaciers in the Himalayas are of concern. Here we present measurements of light-absorbing impurities, known to contribute to the ongoing glacier decrease, in snow from Indian Himalayas and compare them to snow samples from the Finnish Arctic. The soot particles in the snow are shown to have lower light absorbing efficiency, possibly affecting their radiative forcing potential in the snow. Further, dust influences the snow in the Himalayas to a much greater extent than in Finland.

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: Ice-nucleating particle concentrations unaffected by urban air pollution in Beijing, China Jie Chen, Zhijun Wu, Stefanie Augustin-Bauditz, Sarah Grawe, Markus Hartmann, Xiangyu Pei, Zirui Liu, Dongsheng Ji, and Heike Wex Atmos. Chem. Phys., 18, 3523-3539, https://doi.org/10.5194/acp-18-3523-2018, 2018 The ice nucleation activity of urban aerosols in the atmosphere of Beijing was detected in this study. Results showed that ice-nucleating particle (INP) concentrations were not influenced by the highly variable numbers of atmospheric particles, both in mass and particle number concentrations, implying that INP concentrations might not be influenced directly by anthropogenic activities, at least not down to roughly −25 °C and maybe even below.

Description: Environmentally dependent dust chemistry of a super Asian dust storm in March 2010: observation and simulation Qiongzhen Wang, Xinyi Dong, Joshua S. Fu, Jian Xu, Congrui Deng, Yilun Jiang, Qingyan Fu, Yanfen Lin, Kan Huang, and Guoshun Zhuang Atmos. Chem. Phys., 18, 3505-3521, https://doi.org/10.5194/acp-18-3505-2018, 2018 A synergy of ground-based atmospheric chemistry observation, lidar, and numerical modeling was used to investigate a super dust event passing over Shanghai. The degree of dust that was modified by anthropogenic sources highly depended on the transport pathways. A community regional air quality model with improved dust scheme reproduced reasonable dust chemistry results. The chemical and optical properties of evolving dust are crucial for evaluating the climatic effects of dust.

Description: SWRT: A package for semi-analytical solutions of surface wave propagation, including mode conversion, across transversely aligned vertical discontinuities Arjun Datta Geosci. Instrum. Method. Data Syst., 7, 101-112, https://doi.org/10.5194/gi-7-101-2018, 2018 This is a theoretical seismology paper which implements known algorithms for surface wave propagation across single, vertical discontinuities in 2-D media. Seismic surface waves undergo mode conversion at lateral discontinuities and this paper describes a Python software package for accurate computation of these conversion effects, a novel feature not available in the existing seismological literature. This work was done during my PhD research in order to validate a finite-difference wave solver.

Description: Intercomparison of cosmic-ray neutron sensors and water balance monitoring in an urban environment Martin Schrön, Steffen Zacharias, Gary Womack, Markus Köhli, Darin Desilets, Sascha E. Oswald, Jan Bumberger, Hannes Mollenhauer, Simon Kögler, Paul Remmler, Mandy Kasner, Astrid Denk, and Peter Dietrich Geosci. Instrum. Method. Data Syst., 7, 83-99, https://doi.org/10.5194/gi-7-83-2018, 2018 Cosmic-ray neutron sensing (CRNS) is a unique technology to monitor water storages in complex environments, non-invasively, continuously, autonomuously, and representatively in large areas. However, neutron detector signals are not comparable per se: there is statistical noise, technical differences, and locational effects. We found out what it takes to make CRNS consistent in time and space to ensure reliable data quality. We further propose a method to correct for sealed areas in the footrint.

Description: Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations Nicholas Voichick, David J. Topping, and Ronald E. Griffiths Hydrol. Earth Syst. Sci., 22, 1767-1773, https://doi.org/10.5194/hess-22-1767-2018, 2018 This paper describes instances in the Grand Canyon study area and a laboratory experiment in which very high suspended-sediment concentrations result in incorrectly low turbidity recorded with a commonly used field instrument. If associated with the monitoring of a construction or dredging project, false low turbidity could result in regulators being unaware of environmental damage caused by the actually much higher turbidity.

Description: Paleotsunami deposits along the coast of Egypt correlate with historical earthquake records of eastern Mediterranean Asem Salama, Mustapha Meghraoui, Mohamed El Gabry, Said Maouche, Hesham Moussa Hussein, and Ibrahim Korrat Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2018-62,2018 Manuscript under review for NHESS (discussion: open, 0 comments) We study the sedimentary record of past tsunamis along the coastal area west of Alexandria (NW Egypt) taking into account the occurrence of major historical earthquakes in the eastern Mediterranean. Dated charcoal and shell in sedimentary units allow the correlation with the 1870 (Mw 7.5), 1303 (Mw ~ 8) and 365 (Mw ~ 8) large tsunamigenic earthquakes. Our results point out the size and recurrence of past tsunamis and the potential for tsunami hazard over the Egyptian coastline.

Description: The influence of sea surface temperature on the intensity and associated storm surge of tropical cyclone Yasi: a sensitivity study Sally L. Lavender, Ron K. Hoeke, and Deborah J. Abbs Nat. Hazards Earth Syst. Sci., 18, 795-805, https://doi.org/10.5194/nhess-18-795-2018, 2018 This study analyses the influence of sea surface temperature (SST) on the track and intensity of tropical cyclone (TC) Yasi and the associated precipitation and storm surge. A set of regional climate model simulations with SST anomalies varying from +4 to −4 °C are analysed and used to force a storm surge model. Increases in SST lead to an increase in the potential destructiveness of the TC (intensity, rainfall and storm surge), although this relationship is not linear.

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: 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: 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: 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: 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: Computation and analysis of atmospheric carbon dioxide annual mean growth rates from satellite observations during 2003–2016 Michael Buchwitz, Maximilian Reuter, Oliver Schneising, Stefan Noël, Bettina Gier, Heinrich Bovensmann, John P. Burrows, Hartmut Boesch, Jasdeep Anand, Robert J. Parker, Peter Somkuti, Rob G. Detmers, Otto P. Hasekamp, Ilse Aben, André Butz, Akihiko Kuze, Hiroshi Suto, Yukio Yoshida, David Crosp, and Christopher O'Dell Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-158,2018 Manuscript under review for ACP (discussion: open, 0 comments) We present a new satellite data set of column-averaged mixing ratios of carbon dioxide (CO 2 ), which covers the time period 2003 to 2016. We used this data set to compute annual mean atmospheric CO 2 growth rates. We show that the growth rate is highest during 2015 and 2016 despite nearly constant CO 2 emissions from fossil fuel burning in recent years. The high growth rates are attributed to year 2015/2016 El Nino episodes. We present correlations with fossil fuel emissions and ENSO indices.

Description: Ubiquitous influence of wildfire emissions and secondary organic aerosol on summertime atmospheric aerosol in the forested Great Lakes region Matthew J. Gunsch, Nathaniel W. May, Miao Wen, Courtney L. H. Bottenus, Daniel J. Gardner, Timothy M. VanReken, Steven B. Bertman, Philip K. Hopke, Andrew P. Ault, and Kerri A. Pratt Atmos. Chem. Phys., 18, 3701-3715, https://doi.org/10.5194/acp-18-3701-2018, 2018 During summer 2014, atmospheric particulate matter in northern Michigan was impacted by wildfire emissions under all air mass conditions (Canadian wildfires, US urban, and Canadian forest influences). Biomass burning particles coated with secondary organic aerosol contributed the majority of the submicron aerosol mass. Given increasing wildfires, the impacts of biomass burning on air quality must be assessed, particularly for downwind areas impacted by long-range transport.

Description: Modeling reactive ammonia uptake by secondary organic aerosol in CMAQ: application to the continental US Shupeng Zhu, Jeremy R. Horne, Julia Montoya-Aguilera, Mallory L. Hinks, Sergey A. Nizkorodov, and Donald Dabdub Atmos. Chem. Phys., 18, 3641-3657, https://doi.org/10.5194/acp-18-3641-2018, 2018 For the first time, the interaction between ammonia and secondary organic aerosol (SOA) is integrated in an air quality model and investigated on a national scale. Our original analysis from simulation results indicates that a significant reduction in gas-phase ammonia is possible due to its uptake onto SOA. Significant impact is also observed in the concentration of particulate matter, with a distinct spatial pattern over different seasons.

Description: Contrasting behaviors of the atmospheric CO 2 interannual variability during two types of El Niños Jun Wang, Ning Zeng, Meirong Wang, Fei Jiang, Jingming Chen, Pierre Friedlingstein, Atul K. Jain, Ziqiang Jiang, Weimin Ju, Sebastian Lienert, Julia Nabel, Stephen Sitch, Nicolas Viovy, Hengmao Wang, and Andrew J. Wiltshire Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-208,2018 Manuscript under review for ACP (discussion: open, 0 comments) Based on the Mauna Loa CO 2 records and TRENDY multi-model historical simulations, we investigate the different impacts of EP and CP El Ninos on carbon cycle interannual variability. Composite analysis indicates that the evolutions of CO 2 growth rate anomalies have three clear differences in terms of precursors (negative & neutral), amplitudes (strong & weak), and durations of peak (Dec–Apr & Oct–Jan) during EP and CP El Ninos, respectively. Then we further discuss their terrestrial mechanisms.

Description: Multi-generation chemical aging of α -pinene ozonolysis products by reactions with OH Ningxin Wang, Evangelia Kostenidou, Neil M. Donahue, and Spyros N. Pandis Atmos. Chem. Phys., 18, 3589-3601, https://doi.org/10.5194/acp-18-3589-2018, 2018 This study investigates aging in the α-pinene ozonolysis system with hydroxyl radicals (OH) through smog chamber experiments. After an equivalent of 2–4 days of typical atmospheric oxidation conditions, homogeneous OH oxidation of the α-pinene ozonolysis products resulted in a 20–40 % net increase in the organic aerosol concentration and an increase in aerosol O : C by up to 0.04. The relative humidity in the 5–50 % range had a minimum effect on aging.

Description: Analysis of the distributions of hourly NO 2 concentrations contributing to annual average NO 2 concentrations across the European monitoring network between 2000 and 2014 Christopher S. Malley, Erika von Schneidemesser, Sarah Moller, Christine F. Braban, W. Kevin Hicks, and Mathew R. Heal Atmos. Chem. Phys., 18, 3563-3587, https://doi.org/10.5194/acp-18-3563-2018, 2018 This study quantifies the contribution of hourly nitrogen dioxide (NO 2 ) variation to annual NO 2 concentrations at 〉 2500 sites across Europe. Sites with distinct monthly, hour of day, and hourly NO 2 contributions to annual NO 2 were not grouped into specific European regions. Within relatively small areas there were sites with similar annual NO 2 but with differences in these contributions. Therefore, measures implemented to reduce annual NO 2 in one location may not be as effective in others.

Description: Evaluation of OH and HO 2 concentrations and their budgets during photo-oxidation of 2-methyl-3-butene-2-ol (MBO) in the atmospheric simulation chamber SAPHIR Anna Novelli, Martin Kaminsky, Michael Rolletter, Ismail-Hakki Acir, Birger Bohn, Hans-Peter Dorn, Xin Li, Anna Lutz, Sascha Nehr, Franz Rohrer, Ralf Tillmann, Robert Wegener, Frank Holland, Andreas Hofzumahaus, Astrid Kiendler-Scharr, Andreas Wahner, and Hendrik Fuchs Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-134,2018 Manuscript under review for ACP (discussion: open, 0 comments) The impact of the photo-oxidatio of the 2-methyl-3-butene-2-ol (MBO) on the concentration of radicals speces was studied in the atmorpsheric simulation chamber SAPHIR. MBO is avolatile organic compound mainly emitted by ponderosa and lodgepole pines which are very abundant in forest in central-west USA. Very good agreement between measured and modelled radicals concentrations and products from the oxidation of MBO was observed in an environment with NO ~ 200 pptv.

Description: Theoretical analysis of mixing in liquid clouds – Part IV: DSD evolution and mixing diagrams Mark Pinsky and Alexander Khain Atmos. Chem. Phys., 18, 3659-3676, https://doi.org/10.5194/acp-18-3659-2018, 2018 In this paper it is shown that the difference between the mixing diagrams for homogeneous and inhomogeneous mixing is insignificant and decreases with an increase in the DSD width. If the normalized droplet concentration is used, mixing diagrams do not show any significant dependency on relative humidity in the dry volume. The main conclusion of the study is that traditional mixing diagrams cannot serve as a reliable tool in analysis of mixing type.

Description: Evaluation of OH and HO 2 concentrations and their budgets during photo-oxidation of 2-methyl-3-butene-2-ol (MBO) in the atmospheric simulation chamber SAPHIR Anna Novelli, Martin Kaminsky, Michael Rolletter, Ismail-Hakki Acir, Birger Bohn, Hans-Peter Dorn, Xin Li, Anna Lutz, Sascha Nehr, Franz Rohrer, Ralf Tillmann, Robert Wegener, Frank Holland, Andreas Hofzumahaus, Astrid Kiendler-Scharr, Andreas Wahner, and Hendrik Fuchs Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-134,2018 Manuscript under review for ACP (discussion: open, 0 comments) The impact of the photo-oxidatio of the 2-methyl-3-butene-2-ol (MBO) on the concentration of radicals speces was studied in the atmorpsheric simulation chamber SAPHIR. MBO is avolatile organic compound mainly emitted by ponderosa and lodgepole pines which are very abundant in forest in central-west USA. Very good agreement between measured and modelled radicals concentrations and products from the oxidation of MBO was observed in an environment with NO ~ 200 pptv.

Description: How reliable are CMIP5 models in simulating dust optical depth? Bing Pu and Paul Ginoux Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-242,2018 Manuscript under review for ACP (discussion: open, 0 comments) Biases in dust modeling may result in biases in simulating energy budget and regional climate. Output of seven Coupled Model Intercomparison Project Phase 5 (CMIP5) models is examined. Seasonal cycle and spatial pattern of dust optical depth (DOD) in very dusty regions are largely captured by multi-model mean. But observed connections between DOD and local controlling factors such as bareness are not well represented. Future projections by CMIP5 models and a regression model are also analyzed.

Description: Model simulations with COSMO-SPECS: impact of heterogeneous freezing modes and ice nucleating particle types on ice formation and precipitation in a deep convective cloud Karoline Diehl and Verena Grützun Atmos. Chem. Phys., 18, 3619-3639, https://doi.org/10.5194/acp-18-3619-2018, 2018 In deep convective clouds reaching altitudes of 14 km, heavy rain is often formed involving the ice phase. Ice nucleating particles (INPs) are responsible for heterogeneous freezing at middle and lower altitudes. Cloud model simulations indicate that INPs may effect a gradual increase in precipitation at early cloud stages instead of a strong increase at later cloud stages. Simultaneously, the local distribution of precipitation is changed, with more precipitation in the cloud center.

Description: Atmospheric water-soluble organic nitrogen (WSON) in the eastern Mediterranean: origin and ramifications regarding marine productivity Münevver Nehir and Mustafa Koçak Atmos. Chem. Phys., 18, 3603-3618, https://doi.org/10.5194/acp-18-3603-2018, 2018 Atmospheric samples of water-soluble organic nitrogen (WSON) obtained over the eastern Mediterranean have been investigated. Aerosol WSON concentrations exhibited large temporal variation, mainly due to rain and the origin of airflow. WSON originated from agricultural activities, secondary aerosol, nitrate, crustal material and sea salt. In the Cilician Basin, the WSON flux would sustain 33 % and 76 % of the new production of the plant-like organisms in coastal and open waters, respectively.

Description: In situ measurements of desert dust particles above the western Mediterranean Sea with the balloon-borne Light Optical Aerosol Counter/sizer (LOAC) during the ChArMEx campaign of summer 2013 Jean-Baptiste Renard, François Dulac, Pierre Durand, Quentin Bourgeois, Cyrielle Denjean, Damien Vignelles, Benoit Couté, Matthieu Jeannot, Nicolas Verdier, and Marc Mallet Atmos. Chem. Phys., 18, 3677-3699, https://doi.org/10.5194/acp-18-3677-2018, 2018 A campaign was performed in the summer of 2013 above the Mediterranean basin, including in situ counting balloon-borne aerosol measurements (LOAC), for the detection of mineral dust. Three modes in the dust particle volume size distributions were detected, at roughly 0.2, 4, and 30 mm. Particles larger than 40 mm were often observed. They were lifted several days before and their persistence after transport over long distances is in conflict with dust sedimentation calculations.

Description: Gravity Waves excited during a Minor Sudden Stratospheric Warming Andreas Dörnbrack, Sonja Gisinger, Natalie Kaifler, Tanja Portele, Martina Bramberger, Markus Rapp, Micheal Gerding, Jens Söder, Nedjeljka Žagar, and Damjan Jelić Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-228,2018 Manuscript under review for ACP (discussion: open, 0 comments) A deep upper-air sounding stimulated the current investigation of internal gravity waves excited during a minor sudden stratospheric warming (SSW) in the Arctic winter 2015/16. The analysis of the radiosonde profile revealed large kinetic and potential energies in the upper stratosphere without any simultaneous enhancement of upper tropospheric and lower stratospheric values. In combination with high-resolution meteorological analyses we identified an elevated source of gravity wave excitation.

Description: Is Mass Transfer in Secondary Organic Aerosol Particles Intrinsically Slow? Equilibration Timescales of Engine Exhaust and α-Pinene SOA Under Dry and Humid Conditions Khairallah Atwi, Mohamad Baassiri, Mariam Fawaz, and Alan Shihadeh Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-215,2018 Manuscript under review for ACP (discussion: open, 0 comments) Secondary organic aerosols (SOA) influence health and climate. A major simplifying assumption usually made in airshed models is that SOA particles attain instantaneous phase equilibrium with their surroundings. This assumption has been questioned by several recent studies. We generated engine exhaust and biogenic SOA and investigated their evaporation behavior upon dilution. Consistent with current practice, we found that SOA reestablish equilibrium on timescales small enough to be neglected.

Description: How reliable are CMIP5 models in simulating dust optical depth? Bing Pu and Paul Ginoux Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-242,2018 Manuscript under review for ACP (discussion: open, 0 comments) Biases in dust modeling may result in biases in simulating energy budget and regional climate. Output of seven Coupled Model Intercomparison Project Phase 5 (CMIP5) models is examined. Seasonal cycle and spatial pattern of dust optical depth (DOD) in very dusty regions are largely captured by multi-model mean. But observed connections between DOD and local controlling factors such as bareness are not well represented. Future projections by CMIP5 models and a regression model are also analyzed.

Description: Computation and analysis of atmospheric carbon dioxide annual mean growth rates from satellite observations during 2003–2016 Michael Buchwitz, Maximilian Reuter, Oliver Schneising, Stefan Noël, Bettina Gier, Heinrich Bovensmann, John P. Burrows, Hartmut Boesch, Jasdeep Anand, Robert J. Parker, Peter Somkuti, Rob G. Detmers, Otto P. Hasekamp, Ilse Aben, André Butz, Akihiko Kuze, Hiroshi Suto, Yukio Yoshida, David Crosp, and Christopher O'Dell Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-158,2018 Manuscript under review for ACP (discussion: open, 0 comments) We present a new satellite data set of column-averaged mixing ratios of carbon dioxide (CO 2 ), which covers the time period 2003 to 2016. We used this data set to compute annual mean atmospheric CO 2 growth rates. We show that the growth rate is highest during 2015 and 2016 despite nearly constant CO 2 emissions from fossil fuel burning in recent years. The high growth rates are attributed to year 2015/2016 El Nino episodes. We present correlations with fossil fuel emissions and ENSO indices.

Description: Open fires in Greenland: an unusual event and its impact on the albedo of the Greenland Ice Sheet Nikolaos Evangeliou, Arve Kylling, Sabine Eckhardt, Viktor Myroniuk, Kerstin Stebel, Ronan Paugam, Sergiy Zibtsev, and Andreas Stohl Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-94,2018 Manuscript under review for ACP (discussion: open, 0 comments) We simulated the peatland fires that burned Western Greenland in summer 2017. Using satellite data we estimated that the total area burned was about 2345 hectares, the fuel amount consumed about 117 kt C and the emissions of BC about 23.5 t. Smoke plumes were often pushed towards the Greenland Ice Sheet and 30 % of the BC emissions was deposited on snow or ice. This caused a maximum albedo change of 0.006 and a surface radiative forcing of 0.03 W m −2 with local maxima of up to 0.63 W m −2 .

Description: Atmospheric water-soluble organic nitrogen (WSON) in the eastern Mediterranean: origin and ramifications regarding marine productivity Münevver Nehir and Mustafa Koçak Atmos. Chem. Phys., 18, 3603-3618, https://doi.org/10.5194/acp-18-3603-2018, 2018 Atmospheric samples of water-soluble organic nitrogen (WSON) obtained over the eastern Mediterranean have been investigated. Aerosol WSON concentrations exhibited large temporal variation, mainly due to rain and the origin of airflow. WSON originated from agricultural activities, secondary aerosol, nitrate, crustal material and sea salt. In the Cilician Basin, the WSON flux would sustain 33 % and 76 % of the new production of the plant-like organisms in coastal and open waters, respectively.

Description: Is Mass Transfer in Secondary Organic Aerosol Particles Intrinsically Slow? Equilibration Timescales of Engine Exhaust and α-Pinene SOA Under Dry and Humid Conditions Khairallah Atwi, Mohamad Baassiri, Mariam Fawaz, and Alan Shihadeh Atmos. Chem. Phys. Discuss., https//doi.org/10.5194/acp-2018-215,2018 Manuscript under review for ACP (discussion: open, 0 comments) Secondary organic aerosols (SOA) influence health and climate. A major simplifying assumption usually made in airshed models is that SOA particles attain instantaneous phase equilibrium with their surroundings. This assumption has been questioned by several recent studies. We generated engine exhaust and biogenic SOA and investigated their evaporation behavior upon dilution. Consistent with current practice, we found that SOA reestablish equilibrium on timescales small enough to be neglected.

Description: Analysis of the distributions of hourly NO 2 concentrations contributing to annual average NO 2 concentrations across the European monitoring network between 2000 and 2014 Christopher S. Malley, Erika von Schneidemesser, Sarah Moller, Christine F. Braban, W. Kevin Hicks, and Mathew R. Heal Atmos. Chem. Phys., 18, 3563-3587, https://doi.org/10.5194/acp-18-3563-2018, 2018 This study quantifies the contribution of hourly nitrogen dioxide (NO 2 ) variation to annual NO 2 concentrations at 〉 2500 sites across Europe. Sites with distinct monthly, hour of day, and hourly NO 2 contributions to annual NO 2 were not grouped into specific European regions. Within relatively small areas there were sites with similar annual NO 2 but with differences in these contributions. Therefore, measures implemented to reduce annual NO 2 in one location may not be as effective in others.

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: 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: 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: 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: Vegetation history and paleoclimate at Lake Dojran (FYROM/Greece) during the Late Glacial and Holocene Alessia Masi, Alexander Francke, Caterina Pepe, Matthias Thienemann, Bernd Wagner, and Laura Sadori Clim. Past, 14, 351-367, https://doi.org/10.5194/cp-14-351-2018, 2018 The first high-resolution Lake Dojran pollen record for the last 12 500 years is presented. The ecological succession shows Late Glacial steppe vegetation gradually replaced, since 11 500 yr BP, by Holocene mesophilous forests. The first human traces are recorded around 5000 yr BP and increased considerably since the Bronze Age. Pollen data and sedimentological, biomarker and diatom data available from the same core contribute to an understanding of the environmental history of the Balkans.

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.