bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling land use/cover change scenarios in a transboundary catchment
Authors: Chasia Stanley , Olang Luke , Sitoki Lewis , Hernnergger Mathew
Published: March 2020

Changes in land use/cover are among the most important anthropogenic transformation on the physical environment affecting proper functioning of the earth system. Hitherto, land characterization has often been studied using archived satellite data products to understandd trends in space and time. However, due to future uncertainties in land use change in developing countries and the associated impacts on the physical environment, there is need to model these changes at a local scale. A modelling framework to simulate empirically quantified relations between land use and its driving factors was used in the Sio-Malaba-Malakisi catchment between Kenya and Uganda. Changes for the catchment were simulated for a period of 30 years (2017 – 2047) using model parameters that define location characteristics, spatial policies, area restrictions, land use demand and conversion elasticity settings. Elevation, slope, population density, soil organic carbon, soil CEC and precipitation were potential factors selected to evaluate the suitability of devoting a grid cell to a land use type using a stepwise regression model. The scenarios evaluated include first growth, slow growth and an urbanization scenario. The high ROC value in all statistical tests (>0.72) indicated that the spatial distribution of some land use types in the basin could be explained by the selected driving variables. In a fast growth scenario (under policy restriction), areas under open soil and shrubland would be converted to cropland when demand for cash crop goes up in the region. Areas under open trees and marshland outside protected zones, would be converted to agricultural land while barren land with rock outcrops would remain largely unchanged over the period. In a slow growth scenario, expansion of the area under cropland would follow historical trend at 1.25% growth per annum. Marshland areas unsuitable for agricultural expansion are projected to remain the same. In an urbanization scenario, built-up areas would increase steadily at >1% per annum especially in areas earmarked for infrastructural development. In all the scenarios explored, topography, precipitation, soil characteristics and population density were identified as the key drivers of land use change. Results of this study would enhance the understanding of the complexities in projecting future land cover changes and provide baseline data for supporting ongoing soil and land management programs in a data scarce area.

Key words: Land use change; CLUE-S model; Scenario analysis; Sio-Malaba-Malakisi catchment; Transboundary basin
Signature of LULC induced Regional Climate Change over Eastern India: A Modeling and Observational Approach
Authors: Gogoi Partha Pratim , Vinoj Velu
Published: March 2020

The impact of local climate change induced by urbanization or changes in the Land Use and Land Cover (LULC) has been contributing as much as ~50% of the total rise in surface air temperature over the Eastern Indian state of Odisha. While analysing the physical mechanism of such rise, it is found that the changes in the specific heat capacity of the surface regulates the changes in the surface energy budget of the region. A slight change in the energy budget may significantly disturb the regional/local climate balance thereby simulating the primary meteorological parameters such as the temperature and surface heat fluxes. LULC which characterises the surface properties can contribute immensely to the energy budget cycle through biophysical and biochemical processes like evaporation, evapotranspiration, shortwave and long wave radiation, absorption and reflection. In this study, we used observational and modeling techniques to quantify the ramifications of LULC changes on the climate of Odisha during the period 2004-2015. A significant change in the spatial pattern of temperature has been observed towards the eastern part of the region.  We try to find out whether this shift in temperature pattern is because of LULC or global climate forcing. Significant diversification in the agricultural practices have also been noticed in the region in the recent times.  To evaluate such effects, Weather Research and Forecasting (WRF) mesoscale modeling system has been enforced to visualize how significantly changes in LULC have impacted parameters like surface temperature, heat fluxes, humidity etc. However, the modeling results also follow consistency with that of the observational signatures and a rise of ~0.5-1.0 oC has been observed. Along with the spatial analysis, vertical profiles are also studied where we found significant impact of changed LULC on specific humidity and temperature. This study discusses the dynamics of land-atmosphere interactions instigated by local LULC effects.

Keywords: LULC, urbanization, remote sensing, numerical modeling, climate change 
A convolutional neural network with error estimates to reconstruct sea surface temperature satellite observations (DINCAE)
Authors: Barth Alexander , Alvera Azcárate Aida , Licer Matjaz , Beckers Jean-Marie
Published: March 2020

A method to reconstruct missing data in satellite data using a neural network is presented. Satellite observations working in the optical and infrared bands are affected by clouds, which obscure part of the ocean underneath. In this paper, a neural network with the structure of a convolutional auto-encoder is developed to reconstruct the missing data based on the available cloud-free pixels in satellite images. However, it is unclear how to handle missing data (or data with variable accuracy) in a neural network when using incomplete satellite data in the training phase. The present work shows a consistent approach which uses essentially the satellite data and its expected error variance as input and provides the reconstructed field along with its expected error variance as output. The approach is motivated by the way models and observations are combined in the frame of data assimilation. The neural network is trained by maximizing the likelihood of the observed value. The corresponding error variances are estimated during training and do not need to be known a priori. The approach, called DINCAE (Data-Interpolating Convolutional Auto-Encoder) is applied to a relatively long time-series of Advanced Very High Resolution Radiometer (AVHRR) sea surface temperature data and compared to DINEOF (Data Interpolating Empirical Orthogonal Functions), a method to reconstruct missing data based on an EOF decomposition. The reconstruction error of both approaches is computed using cross-validation and in situ observations from the World Ocean Database. DINCAE results have lower error, while showing higher variability than the DINEOF reconstruction. The resulting error estimates are also validated using the cross-validation data and they follow closely the expected Gaussian distribution.
Hydrogeochemistry of Urban Wetlands of Delhi, India
Authors: Joshi Prerna , Siddaiah Neelam Siva
Published: March 2020

Delhi, India’s capital is the second largest urban agglomeration in the world. It is expected to surpass Tokyo to become world’s largest city by 2028 with ~37 million inhabitants (UNDESA, 2018). This rapid growth is characterized by unsystematic urbanization, rapid shifts in its landuse patterns and tremendous pressure on the city’s natural resources. Among other forms of resource degradation, rapidly shrinking and stinking wetlands are of primary concern. Thus evidence-based policy making for their sustainable development and conservation require regular reporting and monitoring of their status.
Present study compares the hydrochemistry of two urban wetlands of Delhi (Sanjay lake and Bhalswa lake) having some crucial differences in their nature and catchment area activities. Surface water quality of these wetlands was studied for winter and summer with respect to their physico-chemical properties (temperature, pH, dissolved oxygen, electrical conductivity, total dissolved solids, alkalinity and hardness) including major ions and trace metals employing standard analytical methods (APHA, 2005). Waters from both the wetlands are alkaline in nature. While pH of Sanjay lake shows a greater variation (7.9 to 10.8), that of Bhalswa lake is fairly constant (8.4 to 8.7), across the seasons. The wetland waters also vary seasonally in their chemistry. Differences in the nature and associated landuse of the wetlands is reflected in their water quality. Hydrogeochemistry of these wetlands were determined by Piper plot and Gibb’s diagram. While water from both the wetlands are Na+- SO42- type during summer, water from Bhalswa lake is Na+- SO42- type and that from Sanjay lake is Ca2+-Mg2+- SO42- type during winter. While water from Bhalswa lake shows an evaporation dominance regime, that from Sanjay lake show dominance of rock-water interaction. Water from both the wetlands are generally unsuitable for drinking purpose. While water from Bhalswa lake is unsuitable for irrigation as well, water from Sanjay lake is generally suitable as determined using various indices (% Na, Residual Sodium Carbonate, Sodium Absorption Ratio, etc.). Both the drinking and irrigational water quality of these wetlands deteriorate during summer. Factor analysis was also used to determine sources of pollution for the two wetlands during both winter and summer. Domestic sewage is observed to be a major source of pollution for both the wetlands. Thus, this study indicates that urban wetlands of Delhi are fast depleting in their health. In light of their importance as a significant urban water resource, a crucial ecological niche and an essential recreational spot for urban areas, there is an urgent need for positive interventions.
PM2.5 organic carbon (OC) and elemental carbon (EC) of summer monsoon season observed at the Anmyeondo Global Atmosphere Watch (GAW) Regional Station, South Korea
Authors: Ham Jeeyoung
Published: March 2020

Organic carbon (OC) and elemental carbon (EC) in PM2.5 were measured with Sunset Laboratory Model-5 Semi-Continuous OC/EC Field Analyzer at Anmyeondo Global Atmosphere Watch (GAW) Regional Station (37°32´N, 127°19´E) in July and August, 2017. It employs TOT (Thermal-Optical-Transmittance) method. The mean values of OC and EC were 3.7 μg m-3 and 0.7 μg m-3, respectively. During the study period, the concentrations of reactive gases and aerosol species were evidently lower than those of other seasons. It is mostly due to meteorological setting of the northeast Asia, where the influence of continental outflow is at its minimum during this season under southwesterly wind. While the diurnal variation of OC and EC were not clear, the concentrations of O3, CO, NOx, SO2, and CO2 were evidently enhanced under easterly wind at night from 20:00 to 8:00. However, the high concentration of EC was observed concurrently with CO and NOx under northerly wind during 20:00 ~ 24:00. It indicates the influence of thermal power plant and industrial facilities, which was recognized as a major emission source during KORUS-AQ campaign. The diurnal variation of O3 clearly showed the influence of land-sea breeze, in which O3 concentration was enhanced with OC in sea-breeze. OC concentration was relatively high, compared to those Seoul. This study suggests that in general, Anmyeondo station serves well as a background monitoring station. However, the variation in meteorological condition is so dynamic that it is primary factor to determine the concentrations of secondary species as well as primary pollutants at Anmyeondo station.

 
Drought effects on the carbon balance and VOC emissions of a tropical rainforest ecosystem
Authors: Bamberger Ines , Daber Lars Erik , Gil Loaiza Juliana , Purser Gemma , De Leeuw Jason , Ladd S. Nemiah , Meredith Laura , Kreuzwieser Jürgen , Werner Christiane
Published: March 2020

Trees contribute substantially to the carbon cycling between the biosphere and atmosphere. Tropical ecosystems in particular are known to exchange not only CO2 with the atmosphere, but also a wide variety of volatile organic compounds (VOCs). With their high reactivity and short life time, VOCs are known to play not only a crucial role in atmospheric chemistry but also in plant signaling and interactions. Due to climate change periods of sustained drought are thought to increase in future and have the potential to alter the carbon balance of tropical ecosystems drastically. However, combined VOC and CO2 flux measurements are rare and thus a quantitative understanding of carbon exchange fluxes in rainforest species during and after drought periods has not yet been reached.

Thus, we used the unique opportunity to study changes of VOC and CO2 flux patterns of the rainforest mesocosm of Biosphere 2 (University of Arizona) in response to an experimentally induced drought period and during the recovery (Biosphere 2 Water, Atmosphere, and Life Dynamics experiment; B2-WALD). This provides us novel information about stress responses of a rainforest ecosystem and its ability to recover, specifically to drought stress. Real-time fluxes of CO2 and VOC exchange were measured by means of 13CO2 laser spectroscopy and proton-transfer-reaction time-of-flight mass-spectrometry (PTR-TOF-MS) using leaf chambers on five different tree and understory species.

While photosynthesis decreased during the drought, changes in VOC flux patterns were more diverse. For example, isoprene emissions increased with dry conditions, whereas fluxes of acetone declined. Here we will present and discuss our first results on leaf gas exchange measurements of different VOCs and CO2 and their response to drought and recovery.
Late Miocene hinterland crustal shortening in the Longmen Shan thrust belt, the eastern margin of the Tibetan Plateau
Authors: Shen Xiaoming , Tian Yuntao , Zhang Shimin , Carter Andrew , Kohn Barry , Vermeesch Pieter , Liu Rui , Li Wei
Published: March 2020

Long‐term (million year time scale) fault‐slip history is crucial for understanding the processes and mechanisms of mountain building in active orogens. Such information remains elusive in the Longmen Shan, the eastern Tibetan Plateau margin affected by the devastating 2008 Wenchuan earthquake. While this event drew attention to fault deformation on the foreland side (the Yingxiu‐Beichuan fault), little is known about the deformation history of the hinterland Wenchuan‐Maoxian fault. To address this gap, thermochronological data were obtained from two vertical transects from the Xuelongbao massif, located in the hanging wall of the Wenchuan‐Maoxian fault. The data record late Miocene rapid cooling and rock exhumation at a rate of 0.9–1.2 km/m.y. from ~13 Ma to present. The exhumation rate is significantly higher than that in the footwall (~0.3–0.5 km/m.y.), indicating a differential exhumation of ~0.6 km/m.y. across the fault. This differential exhumation provides the first and minimum constraint on the long‐term throw rate (~0.6 km/m.y) of the Wenchuan‐Maoxian fault since the late Miocene. This new result implies continuous crustal shortening along the hinterland fault of Longmen Shan, even though it has not been ruptured by major historic earthquakes. Our study lends support to geodynamic models that highlight crustal shortening as dominating deformation along the eastern Tibetan Plateau.
Influence of the synoptic systems and inversion characteristics on winter heavy air pollution in the lower atmosphere over Sichuan Basin, China
Authors: Wang Shigong , Fu Hua
Published: March 2020

The Sichuan Basin is located in the eastern part of the Tibetan Plateau, and there is a rapidly developing urban agglomeration over there. Therefore, heavy air pollution events have frequently occurred over many cities in recent decades. In this study, We explored the effects of weather systems on winter heavy air pollution from more than 10 cases of heavy air pollution events occurred during 2006-2018. Most of them were affected by a dry low-pressure system at 700 hPa, at the same time , they were also influenced by the inversion with several layers in the lower atmosphere. It is interesting that the synergistic effects of synoptic patterns and inversions caused by topography on heavy air pollution events. When the urban agglomeration was in front of the low-pressure system and the weather conditions were controlled by a warm southerly air flow, a strong temperature inversion appeared above the atmospheric boundary layer acting as a lid. The local secondary circulation was forced by both of them and was confined within the atmospheric boundary layer. At that time, the horizontal wind speed in the lower atmosphere was low.  As a result, vertical mixing and horizontal dispersion in the atmosphere were poor, a heavy air pollution event was gradually caused. After the low-pressure system had passed over the urban agglomeration, the weather conditions over there were controlled by a dry and cold air flow from the northwest at 700 hPa, foregoing strong inversion layer gradually dissipated, the secondary circulation enhanced and uplifted, and the horizontal wind speed in the lower atmosphere also increased, resulting in a sharp decrease in the concentration of air pollutants. In sum, the strong inversion layers above the lower atmosphere were induced by the low-pressure systems at 700 hPa, both happened a synergistic effect and played a key role in the formation of heavy air pollution during the winter months in this urban agglomeration of The Sichuan Basin. Finally, it was presented that a new conceptual model is about meteorological causes of winter heavy air pollution  in the Sichuan Basin.
Operational uncertainty and sensitivity analyses of a model assessing water catchment vulnerability to pesticides
Authors: Rudi Gabrielle , Lalande Nathalie , Louchart Xavier , Bailly Jean-Stéphane
Published: March 2020

Public authorities, in response to the Water Framework Directive, impose to take measures to protect catchments that provide drinking water when the levels of contamination exceed (or are susceptible to exceed) drinking water standards. Companies and public research institutes involved in the transformation of conventional agricultural practices are therefore engaged in the development of methods aiming at assessing the vulnerability of territories towards diffuse pollutions. This poster presents an uncertainty and sensitivity analysis on a model able to assess the vulnerability towards hydrological transfers of pesticides. This research work helps to enhance the reliability of the information that is given to public authorities regarding priority areas for reduction of pesticide use. 

The research is being conducted in an agricultural study area located in the center of France (30km2). The studied model makes calculations based on cartographic data (DTM, soil properties, hydrographic network, climate, land cover) to identify vulnerable plots and subcatchments, on the basis of institutional guidelines for pesticide risk transfer assessment. Considered uncertainties for the analysis are the accuracy and resolution of the input cartographic data, as well as the parameterization of the model. The results highlight that these uncertainties can influence, in some cases significantly, the outputs of the model and therefore information given to public authorities. This research collaboration between two French public research institutes (INRAE, AgroParisTech) and a private company (Envilys) on an operational case study allows to identify levers to enhance the reliability of outputs from vulnerability models and in turn the efficiency of measures for catchment protection. It also allows the determination of the resolution of vulnerability mapping outputs according to obtained uncertainties. 
Oxygen-fire-vegetation feedbacks and the distribution of Earth’s biomes
Authors: Vitali Rayanne , Belcher Claire , Kaplan Jed , Sitch Stephen , Watson Andrew
Published: March 2020

Oxygen has varied in its abundance in the atmosphere throughout Earth’s long –term evolutionary history. Laboratory experiments have shown that fire responds rapidly to oxygen changes. Therefore it has been suggested that increases and decreases in atmospheric oxygen levels have influenced fire frequency, fire behaviour and plant evolutionary adaptations to fire.

Recent research has indicated that periods with high atmospheric oxygen, such as the Cretaceous period, which also saw the evolution of new plant groups had the coupled effect of altering fire behaviour. Such modelled fire behaviour has been able to estimate that fires during this period would have been more intense and spread more rapidly which likely fed back to changes in ecosystem dominance. However, we are lacking understanding of how oxygen driven changes in fire might feedback to influence the dominance and distribution of land-surface vegetation cover across Earth’s surface throughout Earth history.

Here I will present, a series of oxygen-fire-land cover simulations using the LPJ-LMfire Dynamic Global Vegetation Model that considers how oxygen-mediated changes in fire frequency and behaviour lead to changes in dominance of selected plant functional types within Earth’s biomes and influence the total land area covered by forest.

Our aim being to explore the coupled influence of oxygen and a climate on vegetation distributions mediated by fire throughout Earth’s past such that we can work towards understanding the balance of natural fire feedbacks to the Earth system versus human interrupted fire feedbacks in our modern day.
Influence of Aeolus data assimilation on the representation of gravity waves in ECMWF analysis fields
Authors: Krisch Isabell , Rennie Michael , Kaifler Bernd , Gisinger Sonja , Reitebuch Oliver , Rapp Markus
Published: March 2020

In January 2020, the European Centre for Medium-Range Weather Forecast (ECMWF) became the first numerical weather prediction (NWP) centre to assimilate wind observations from the new European Space Agency (ESA)’s Earth Explorer satellite Aeolus for operational forecasting. Aeolus was launched into space on August 22nd, 2018, carrying the world’s first spaceborne wind lidar, the Atmospheric Laser Doppler Instrument (ALADIN). ALADIN measures profiles of line-of-sight wind components from 30km altitude down to the Earth’s surface or to the level where the lidar signal is attenuated by optically thick clouds.

Impact assessment studies performed at ECMWF in 2019, show improved weather forecasting skills, by assimilating Aeolus wind measurements. As a side effect, these impact experiments also reveal an influence of Aeolus data assimilation on the representation of resolved gravity waves in the ECMWF model fields. Both, orographic and non-orographic gravity waves are impacted by the Aeolus data assimilation.

This impact of Aeolus data assimilation on the representation of gravity waves in ECMWF will be presented for selected case studies in the southern hemisphere. Ground-based and airborne measurement data from the SOUTHTRAC campaign will be used for validation where available.
Spatial heterogeneity and temporal variability in repeated hillslope tracer experiments
Authors: Bogner Christina , Steininger Florian , Hauhs Michael
Published: March 2020

Subsurface flow in small first-order catchments is dominated by both, precipitation patterns and subsurface structure. We report on a series of repeated tracer experiments under transient conditions in a small forested first-order catchment (F4, 2.3 ha) at Gårdsjön in SW Sweden. Podsols are the dominant soil types, soil thickness varies strongly (0-50 cm) and bedrock outcrops are partly visible at the surface. A small wetland is situated directly upstream of the runoff weir. A hillslope of the catchment is equipped with a sprinkler system and can be irrigated at around 38-45 m3 day-1. Depending on the meteorological conditions in the respective year of the experiment, natural rainfall comes in addition.

A bromide tracer solution was injected into groundwater at a single location about 40 m upstream the weir over a period of approximately an hour, and was monitored using a set of groundwater tubes and the weir at the outlet over the following 3-4 days. Additionally, discharge and meteorological conditions were recorded. The experiments were repeated each summer from 2007 to 2019. In summer 2019, electrical resistivity tomography was done during the experiment. We measured a profile perpendicular to the flow direction covering the whole study site. This data shows how subsurface patterns could influence water flow on the soil-bedrock interface. We investigated tracer recovery rates against cumulated runoff since tracer application. Substantially different transit times and qualitatively different behaviour of the breakthrough curves were observed, even under steady state conditions. We present first results how these differences could be linked to the structure of the subsurface.
Determination of trace elements and macronutrients in agricultural soils using energy dispersive X-ray fluorescence as a rapid and precise analytical technique
Authors: Croffie Maame , Williams Paul N. , Fenton Owen , Fenelon Anna , Metzger Konrad , Daly Karen
Published: March 2020

X-ray fluorescence spectrometry (XRF) is a rapid and inexpensive method for soil analysis. Although, not as precise and accurate as mineral acid digestion-Inductively Coupled Plasma spectrometry for soil testing at present, the XRF method has the potential to be optimised. The objective of this study was to reduce moisture effects, particle size effects and spectra interferences on trace element and macronutrient analyses by improving soil sample preparation and XRF calibration, using bench top Energy-dispersive X-ray Fluorescence Spectrometry (EDXRF). The soil particle size effects study involved samples prepared as pressed powders, pressed pellets, and pressed pellets with a wax binder. After which, the recoveries of Al, Cr, Ni, Mn, Pb, Ca, Fe, K, Mg, P, S and Zn were evaluated as a measure of accuracy and precision. The XRF was calibrated with the fundamental parameters (FP) and matching library (FPML) methods to reduce spectral interferences and validated with certified reference materials. In addition, both XRF methods (FP and FPML) were compared with aqua regia digestion (acid digestion) -Inductively Coupled Plasma-Optic Emission Spectrometry (ICP-OES) using concordance correlation coefficient (CCC), whereby a value of 1 indicated good agreement between methods. There were significant differences (p<0.05) between the sample preparation methods and the pressed pellet with wax binder had the best accuracy and precision for all the elements. In addition, for the calibration study, the FPML gave better recoveries of Ni, Ca, Mg, S, P, Cr compared to the FP, however, for Fe, Zn, K and Mn the FP had better recoveries than the FPML. Furthermore, there was good agreement (CCC>0.80) between both XRF methods and ICP-OES for all elements except Al, P, Cu, K, S and Cr (CCC<0.60). Aqua regia digestion underestimated the total concentration of Al and K, thus, the XRF had better accuracy for predicting these elements. However, for Cr, S, Cu and P, the XRF overestimated the concentration of these elements in soil. This study has shown that the XRF is as accurate as the ICP-spectrometry for most elements when properly calibrated with the advantage of having a shorter sample preparation. Thus, environmental analysts can monitor soils frequently using the XRF without losing analytical results especially with Al and K and also incurring substantial costs in analyses as with traditional methods. 

Keywords: soil; elemental analysis; X-Ray Fluorescence; spectrometry; calibration

 
Magma chamber formation by magma intrusion into the Earth's crust
Authors: Utkin Ivan , Melnik Oleg
Published: March 2020

The main mechanism of transport of magma in the Earth’s crust is the formation of cracks, or dikes, through which the melt moves towards the surface under the action of buoyancy forces and tectonic stresses. Due to the structural features of the crust or external stress fields, dikes often do not reach the surface, but penetrate the localized region in which the rocks melt, leading to the formation of magmatic chambers, whose volume can exceed thousands of cubic kilometers. We present a model of the formation of a magma chamber during the intrusion of dikes at a given flow rate. The model is based on the solution of heat equation and considers the actual melting diagrams of magma and rocks. It Is shown that, in case of magmatic fluxes typical of island arc volcanoes, magma chambers are formed over hundreds of years from the beginning of magma intrusion. The influence of the magma flow rate, the size of the dikes and their orientation on the volume of the formed magma chamber and its shape was investigated. The size of the chamber significantly exceeds the area of dike intrusion due to the displacement of magma and rocks of the crust, their heating up and melting. To calculate displacement of rock and magma in a numerical simulation, a hybrid method based on PIC/FLIP interpolation is developed, making it possible to avoid unphysical mixing due to numerical dissipation, thus preserving the fine details of the formed magma chamber.

This work was supported by RFBR, project number 18-01-00352
Comparing water, energy and entropy budgets of aquaplanet climate attractors
Authors: Ragon Charline , Lembo Valerio , Lucarini Valerio , Kasparian Jérôme , Brunetti Maura
Published: March 2020

The climate system can be seen as a thermal engine that generates entropy by irreversible processes and achieves a steady state by redistributing the input solar energy among its different components (ocean, atmosphere, etc) and by balancing the energy, water mass and entropy budgets over all the spatial scales. Biases in modern climate models are generally related to the fact that their statistical properties are not well represented, giving rise to imperfect closures of the energy cycle. Thus, a proper measurement of the efficiency of the thermal engine in each climate model is needed. Moreover, possible steady states (attractors) that can be approached at climate tipping-points are characterised by different feedbacks becoming dominant in the thermal engine.

We apply the Thermodynamic Diagnostic Tool (TheDiaTo) [1] to the attractors recently obtained using the MIT general circulation model (MITgcm) in a coupled aquaplanet [2], a planet where the ocean covers the entire globe. Such coupled aquaplanets, where nonlinear interactions between atmosphere, ocean and sea ice are fully taken into account, provide a relevant framework to understand the role of the main feedbacks at play in the climate system. Five attractors have been found, ranging from snowball (where ice covers the entire planet) to hot state conditions (where ice completely disappears) [2].

Using TheDiaTo, we analyse the five climate attractors by estimating:  a) the energy budgets and meridional energy transports; b) the water mass and latent energy budgets and respective meridional transports; c) the Lorenz Energy Cycle; d) the material entropy production. We consider different coupled atmosphere-ocean-sea ice configurations and cloud parameterizations of MITgcm where the energy balance at the top of the atmosphere is progressively better closed in order to understand the occurrence of possible biases in the statistical properties of each attractor.

Our contribution will help clarify the thermodynamic differences in climate attractors and their stability to external perturbations that could shift the climate from a steady state to the other.

[1] Lembo V., Lunkeit F., Lucarini V., TheDiaTo (v1.0) – a new diagnostic tool for water, energy amd entropy budgets in climate models, Geosci. Model Dev. 12, 3805-3834 (2019)

[2] Brunetti M., Kasparian J., Vérard C., Co-existing climate attractors in a coupled aquaplanet, Climate Dynamics 53, 6293-6308 (2019)
Trans- and interdisciplinary research - Running a Graduate Research School across the Atlantic Ocean
Authors: van den Bogaard Christel , Laing Kirsten
Published: March 2020

Understanding ocean and atmosphere dynamics in the Atlantic Ocean is the goal of the HOSST-TOSST Research school  "Transatlantic Ocean System Science and Technology“. At the heart of the project is the introduction of science work across topics of the North Atlantic Ocean System. Our goal is motivating the young researcher to consider and engage with various aspects of ocean research beyond their own special field of research. For this we have established a weekly seminar series with video system support.  It allows us to stay in contact even with an ocean between us.  Being able to stay in contact, we meet once a year in person in a joint summer school, setting up topics outside the immediate research areas and have all participants work in small groups. Co-supervision of doctoral thesis and extended research exchanges at the partner University, working with the co-supervisors research group, are fundamental for the full transatlantic research experience.

The poster and our presence will give interested persons the chance to learn from our experience how to enable a good group dynamic in the research school. Providing the basics for the best interdisciplinary research. Come and learn from our experience of establishing a dynamic research network across the Atlantic. 
On the use of cross-polarized SAR and GPS-sonde measurements for wind speed retrieval in tropical cyclones
Authors: Poplavsky Evgeny , Rusakov Nikita , Ermakova Olga , Troitskaya Yuliya , Sergeev Daniil , Balandina Galina
Published: March 2020

The current investigation is concerned with the study of the dependence of the scattered cross-polarized microwave signal from the Sentinel-1 satellite on the parameters of the marine atmospheric boundary layer based on data obtained from falling NOAA GPS-sondes under tropical cyclone conditions.
Field measurements and remote sensing data for hurricanes in the Atlantic and Pacific oceans were analyzed for the period 2016 - 2018. Based on the analysis of data measured by GPS-sondes, averaged wind speed profiles were obtained, while the parameters of the atmospheric boundary layer (drag coefficient and wind friction velocity) were retrieved using the self-similarity property of velocity profiles from measurements in the “wake” part.
Sentinel-1 SAR images were used as remote sensing data. Images with cross polarization have a high level of thermal noise (NESZ), which leads to errors when retrieving the NRCS. In this regard, preliminary image processing was performed in the SNAP application.
Using the obtained parameters of the atmospheric boundary layer, the data of GRS-sonde measurements and Sentinel-1 SAR images on cross polarization were collocated and the dependences of the NRCS on the parameters of the atmospheric boundary layer were obtained.

This work was supported by the RFBR projects No. 19-05-00249, 19-05-00366, 18-35-20068 (remote sensing data analysis) and RSF No. 19-17-00209 (GPS-sondes data assimilation and processing).
Planktic foraminiferal I/Ca from Holocene sediments of the Pacific and Indian Ocean
Authors: Winkelbauer Helge Arne , Chenery Simon , Hamilton Elliott Montagu , Leng Melanie , Hoogakker Babette
Published: March 2020

Current climatic trends are expected to lead to expansion of oxygen minimum zones and an overall decrease in oxygen concentration [O2] in the oceans. In order to improve predictions of future trends we need to create a better understanding of the natural oxygen cycle. The iodine to calcium ratio (I/Ca) of planktonic foraminifera is an increasingly popular proxy to assess upper water column oxygenation. Recent studies suggest that this ratio is mainly controlled by subsurface water dissolved oxygen concentrations. A thorough assessment of the proxy has been carried out for the South Atlantic, but is currently lacking for the Indian and Pacific Oceans, which contain the worlds’ most intense and large oxygen minimum zones. Here we present results of recent (Holocene) planktonic foraminifera (mixed layer and deep dwelling species) I/Ca measurements across a range of oceanographic conditions ([O2] varies between < 10 µmol/kg to > 200 µmol/kg) from the Indian and Pacific Ocean to further refine the proxy, using sample material provided by Lamont-Doherty Core Repository.
North Atlantic Oscillation, East Atlantic pattern and jet variability since 1685
Authors: Mellado-Cano Javier , Barriopedro David , García-Herrera Ricardo , Trigo Ricardo , Hernández Armand
Published: March 2020

Instrumental records of the leading patterns of variability are short, hampering a proper characterization of the atmospheric circulation beyond the mid-19th century. In this work, recently published in Mellado-Cano et al. (2019), we present the longest (1685-2014) observational-based records of winter NAO and East Atlantic (EA) indices as well as estimates of the North Atlantic eddy-driven jet stream for the same period. They are inferred from wind direction observations over the English Channel assembled in monthly indices of the persistence of the wind in the four cardinal directions. Our NAO and EA series are significantly correlated with traditional indices, showing comparable skill to that obtained between some instrumental indices, and capture their main signatures on European temperature and precipitation.

By identifying winters with different combinations of NAO/EA phases in the 20th century, our results highlight the additional role of EA in shaping the North Atlantic action centers and the European climate responses to NAO. The joint effects of NAO and EA cause European surface climate anomalies that can substantially differ from their canonical signatures, meaning that a proper characterization of regional climates cannot be achieved by the NAO alone. The EA interference with the NAO signal is stronger in precipitation than in temperature and affects areas with strong responses to NAO such as Greenland and the western Mediterranean.

The time series display large variability from interannual to multidecadal time scales, with e.g. positive (negative) EA (NAO) phases dominating before 1750 (during much of the 19th century). The last three centuries uncover multidecadal periods characterized by specific NAO/EA states and substantial variability in the North Atlantic jet stream, thus providing new evidences of the dynamics behind some outstanding periods. Transitions in the NAO/EA phase space have been recurrent and pin down long-lasting anomalies, such as the displacement of the North Atlantic action centers in the late 20th century, besides some disagreements between historical NAO indices.

Mellado-Cano, J., D. Barriopedro, R. García-Herrera, R.M. Trigo, 2019: Examining the North Atlantic Oscillation, East Atlantic pattern and jet variability since 1685. Journal of Climate. doi: https://doi.org/10.1175/JCLI-D-19-0135.1
What Framework Promotes Saliency of Climate Change Issues on Online Public Agenda: A Quantitative Study of Online Knowledge Community Quora
Authors: Shi Wen
Published: March 2020

Though scientists have achieved consensus on the severity and urgency of climate change years ago, the public still considers this issue not that important, as the influence of climate change is widely thought to be geographically and temporally bounded. The discrepancy between scientific consensus and public's misperception calls for more dedicated public communication strategies to get climate change issues back on the front line of public agenda. Based on the large-scale data acquired from the online knowledge community Quora, we conduct a computational linguistic analysis followed by regression model to address the climate change communication from the agenda setting perspective. To be specific, our results find that certain narrative strategies may make climate change issues more salient by engaging public into discussion or evoking their long-term interest. Though scientific communicators have long been blaming lack of scientific literacy for low saliency of climate change issues, cognitive framework is proved to be least effective in raising public concern. Affective framework is relatively more influential in motivating people to participate in climate change discussion: the stronger the affective intensity is, the more prominent the issue is, but the affective polarity is not important. Perceptual framework is most powerful in promoting public discussion and the only variable that can significantly motivate public's long-term desire to track issues, among which feeling plays the most critical role compared with seeing and hearing. This study extends existing science communication literature by shedding light on the role of previously ignored affective and perceptual frameworks in making issues salient and the conclusions may provide theoretical and practical implications for future climate change communication.
Global variability of aerosol physical properties retrieved from the network of GAW near-surface observatories
Authors: Rose Clémence ,   co-workers
Published: March 2020

Due to their multiple effects on climate and human health, aerosol particles are a key component of the Earth’s atmosphere. The understanding of these effects however remains incomplete, which in turn affects their quantification at the present time as well as future predictions. These limitations highlight the need for continuing the efforts to organize long term monitoring of the climate-relevant aerosol properties in as broad a network as possible.

The value of such measurements, which are performed in compliance with homogenous protocols and meet high quality standards, is clearly demonstrated in the present analysis. This work, which is focused on the particle number concentration and particle number size distribution (PNSD), is part of a wider project, one of the objectives of which is to document the variability of climate-relevant aerosol properties based on available in-situ near-surface measurements. To investigate the spatial variability of the abovementioned aerosol physical properties, observations collected at 57 sites connected to the Global Atmosphere Watch (GAW) network were analysed for a reference year (2017). Measurements performed with condensation particle counters (CPC, 21 sites) and mobility particle size spectrometers (MPSS, 36 sites) were both included in the analysis; in the latter case, the total particle number concentration, Ntot, was calculated over the diameter range 10 – 500 nm.

As a result of enhanced sources, Ntot is generally higher during warmer seasons at all sites (in connection with atmospheric boundary layer dynamics for mountain sites). In addition, based on available MPSS data, the major contribution of Aitken mode particles (30-100 nm) to the total particle number concentration also appears as a common feature of all environments. In contrast, the observed levels of Ntot, between 101 and 104 cm-3, and the magnitude of its seasonal cycle, exhibit, together with the variations of the PNSD, some distinctive behaviour for the different geographical categories and environmental footprint classes, with additional site-dependent characteristics. Among other factors (including the nature and proximity of the particles sources), the level of anthropogenic influence appears to strongly affect the observations.

This work will be completed in the near future with a trend analysis to document the temporal variability of the particle number concentration and PNSD.
A Double-Disturbed Lunar Plasma Wake
Authors: Rasca Anthony , Fatemi Shahab , Farrell William , Poppe Andrew , Zheng Yihua
Published: March 2020

Under nominal solar wind conditions, a low density wake region forms downstream of the nightside lunar surface.  However, the lunar plasma environment undergoes a transformation as the Moon passes through the Earth’s magnetotail, with the warm plasma typically not having a strong flow, and thus the wake structure disappears.  However, while in the tail, there can be a sudden intense change due to solar-driven events such as coronal mass ejections.  With a new planned human presence on the Moon, it is important to understand the near-surface plasma environment’s response to these extreme conditions.  We investigate the response of the lunar wake to a passing coronal mass ejection on 2012 March 8 while crossing the Earth’s magnetotail using both a large-scale MHD model of the Earth’s global magnetosphere and smaller-scale 3-D hybrid-PIC simulations.

The CME plasma shock was detected by the Wind spacecraft around 10:30 UT and in the Earth’s magnetotail around 11:20 UT by the ARTEMIS spacecraft in lunar orbit.  Wind observations are used as time-dependent up-stream conditions for a 24-hour global magnetosphere MHD simulation run through NASA’s Community Coordinated Modeling Center using the OpenGGCM model.  Extracted plasma parameters from the ARTEMIS spacecraft following the plasma shock are used as upstream static boundary conditions for hybrid-PIC simulations using the AMITIS code.

Results for the hybrid-PIC lunar wake simulations performed during a momentary jump in magnetotail plasma velocity and density show a short misaligned plasma void relative to nominal SW conditions.  MHD results indicate that changes near the Moon appear as a result of a warped magnetopause boundary moving inward after 11:00 UT, causing the Moon to enter the magnetosheath.  These results also show a number of plasmoids developing and propagating down the tail, including one seen at 11:20 UT that corresponds temporarily with plasmoid-like features in the ARTEMIS magnetic field profiles.
Waveform tomography in the Mediterranean and Southeast Asia
Authors: Blom Nienke , Fichtner Andreas , Gokhberg Alexey , Rawlinson Nicholas , Wehner Deborah
Published: March 2020

In this work, we present results from waveform tomography conducted in the Mediterranean and Southeast Asia. Whilst computationally more expensive than ray-based imaging methods, the advantage of waveform methods lies in their ability to incorporate in a consistent manner all the information contained in seismograms – not just the arrivals of certain, specified phases. We can therefore naturally and coherently exploit body and multimode surface waves, and take into account source effects, frequency-dependence, wavefront healing, anisotropy and attenuation.

Here, we look at applications of this method in two geologically complex regions: the Mediterranean and Southeast Asia. Both are characterised by broadscale convergence and a complicated pattern of interactions between larger and smaller-scale tectonic plates.

The Mediterranean is historically one of the best studied areas in the world, with an impressive density of seismic stations which greatly aids the detailed imaging of the region. We have been able to image the Central and Eastern Mediterranean down to the mantle transition zone, thereby illuminating the complex slab structures and geometries within the domain. We identify several main slabs that correspond to major current and former subduction zones.

In Southeast Asia, we work at a larger scale, with a model domain encompassing the Sunda arc (which gives rise to some of the world’s most significant natural hazards), the Banda arc with its spectacular 180° curvature and various smaller-scale features, such as the tectonically complex island of Sulawesi. To date, sparse instrument coverage in the region has led to a heterogeneous path coverage, in particular around Borneo which is located in an intra-plate setting. A recent series of temporary seismometer deployments in Sabah (North Borneo), Kalimantan, Sulawesi and the Celebes Sea allows us to fill the gaps in the publicly available data, thereby providing new opportunities to investigate the region's complexity using waveform tomography.

In this presentation, we will also discuss a number of features and “best practices” that can significantly influence waveform tomography results. In particular, we highlight how we can optimise sensitivity to deep structure by combining long-period data with a window selection approach that specifically targets body wave signals, and we discuss the effect of uncertainties in earthquake source parameters on the seismic inversion process.