bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploration of Atmospheric Compositions by TROPOMI on Sentinel-5P
Authors: Zeng Jian , Gerasimov Irina , Adams Jennifer , Huwe Paul , Wei Jennifer , Meyer David
Published: March 2020

Since its launch in October 2017, the Sentinel-5 Precursor (Sentinel-5P), one of the European Commission’s new Copernicus family – Sentinels, has continuously proven to be successful, enhanced, and upgraded to its predecessor missions. The sole payload on Sentinel-5P is the TROPOspheric Monitoring Instrument (TROPOMI), which is a nadir-viewing 108 degree Field-of-View push-broom grating hyperspectral spectrometer, covering the wavelength of ultraviolet-visible (270 nm to 495 nm), near infrared (675 nm to 775 nm), and shortwave infrared (2305 nm - 2385 nm). Sentinel-5P is currently providing measurements of total column ozone, tropospheric nitrogen dioxide and formaldehyde, sulfur dioxide, methane, carbon monoxide, aerosol index and cloud at very high spatial resolutions. Ozone vertical profile products are scheduled to become available in April 2020. In addition, S5P/TROPOMI spectral design provides the possibility of developing other atmospheric composition products such as BrO, aerosol optical depth, sun-induced fluorescence, etc..

 

The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is one of the 12 Distributed Active Archive Centers (DAACs) within NASA's Earth Observing System Data and Information System (EOSDIS). The GES DISC archives and supports over a thousand data collections in the Focus Areas of Atmospheric Composition, Water & Energy Cycles, and Climate Variability. Under the End User License Agreement between NASA, European Space Agency (ESA) and European Commission (Copernicus Programme), GES DISC is curating S5P/TROPOMI Level-1B and Level-2 products and providing information services through enhanced tools and services that offer convenient solutions for complex Earth science data and applications. This presentation will demonstrate up-to-date TROPOMI products and their applications, as well as various efficient yet straightforward methods to access, visualize and subset TROPOMI data at GES DISC.
Application of quasi 150 day rhythm method in the prediction of strong cold air extension period in spring in Gansu Province
Authors: Lin Shu , Li Danhua , Lu Guoyang , Liu Weiping
Published: March 2020

Using daily minimum temperature of 77 stations in Gansu in spring 1981-2018,temporal and spatial distribution characteristics of strong cold air are analyzed in spring in Gansu Province in the past 38 years. The frequency of strong cold air in spring in Gansu was the lowest in 1980s，it increased since the new century. Strong cold air in the whole province and Hedong area mainly appeared in March and April, The strong cold air in Hexi area is more than April and May. The frequency of strong cold air in Hexi area is two times of that in Hedong area. Using NCEP daily 500hPa height field data for 1981-2018 and quasi 150 day rhythm method, the prediction of extended period of the strong cold air in spring in Gansu province was studied. The threshold value of circulation similarity is determined , evaluation criteria and multiple screening are established. Developing  evaluation criteria and multilayer screening, and selecting 4 typical weather forecasts of strong cold air in spring in Gansu province by calculating similarity coefficients and determining thresholds. In the case of 4 typical fields being applied at the same time, the prediction accuracy is obviously improved, the null rate is reduced to zero, and the omission rate is greatly reduced, which provides a new idea for the extended forecast of the strong cold air in Gansu.
Isotope tools scaling soil microbial ecology to biogeochemistry
Authors: Hungate Bruce
Published: March 2020

Microorganisms influence the composition of the atmosphere, the cycling of elements within and through ecosystems, the functioning of agricultural ecosystems on which humans depend, and human health. Microorganisms are also the most metabolically flexible and the most taxonomically and evolutionarily diverse organisms on Earth. Yet deciphering how that diversity imprints on the processes they influence at larger scales has proven challenging, because of the overwhelming complexity of microbial communities, and because of the difficulty of quantifying how microbial taxa assimilate and transform elements in the environment. New approaches that blend traditions from microbial ecology and ecosystem science make it possible to explore how the diversity and physiology of microorganisms shape ecosystem biogeochemistry and how it responds to global environmental change. Quantitative stable isotope probing has revealed cases where ‘omics data scales to quantitative ecology and biogeochemistry. Lab and field warming experiments in tropical, temperate, boreal, and arctic ecosystems point to generalized relationships between microbial growth rates (measured using isotope-enabled omics) and carbon release from soil through respiration (measured at the whole-system scale using classic techniques). Phylogenetic signals describe these relationships, indicating the potential for grounding biogeochemistry within the evolutionary histories of the organisms involved. In a meta-analysis across 27 independent experiments, quantitative stable isotope probing also indicates the general importance of predatory bacterial taxa in microbiomes, a role that increases in response to resource pulses, and which may provide a trophic theoretical underpinning to processes like the soil priming effect. More generally, such approaches hold potential for linking microbial diversity to carbon and element cycling in ecosystems. Historically, the diversity, complexity, and intractability of microbial ecosystems has relegated their study to either a reductionist descriptive tradition in microbial ecology or to a simplistically quantitative one in ecosystem science. Yet, new ideas and tools are poised to push microbial ecology forward to a point where it can more meaningfully integrate with ecological fields at larger scales, from populations to ecosystems to the globe.
Soil hydrology and crop evapotranspiration modeling in a dry agricultural region of the Tibet Plateau
Authors: Wang Jiaxin , Zhao Xining , Gao Xiaodong
Published: March 2020

Vapor flow plays major role in soil–atmosphere water exchange in arid regions, and can be partly driven by airflow, but its impact is often neglected. In this study, a two-year field experiment was conducted in a dry agricultural region on the Tibet Plateau (TP) to investigate the effect of airflow on soil hydro–thermal dynamics and evapotranspiration modeling under three cultivation patterns: ridge-furrow planting with black-film mulching (RM), flat planting with black-film mulching (FM), and flat planting with no mulching (FN). An airflow-incorporated, based on Philip and de Vries (PdV) model, STEMMUS (Simultaneous Transfer of Energy, Mass and Momentum in Unsaturated Soil) was adopted. Considering objective’s (Lycium barbarum L.) sparse canopy, excluding Penman-Monteith (P-M) algorithm which already employed in STEMMUS, Shuttleworth-Wallace (S-W) model was incorporated into STEMMUS model to simulate evapotranspiration rate. Validation results showed that STEMMUS reliably captured the behaviors of observed soil moisture, soil temperature, and evapotranspiration (index of agreement d = 0.4, 0.6 and 0.5 for soil moisture under FN, FM and RM; 0.9 for soil temperature under three treatments; 0.6, 0.6 and 0.8 for evapotranspiration under FN, FM and RM; 0.6, 0.5 and 0.5 for evaporation under FN, FM and RM). Incorporating airflow extended the 0-1 m soil profile temperature modeling precision (d value improved 1%), led to the maximum 5% gap of soil moisture at 20 cm depth, and 3.7 mm d-1 gap of daily evapotranspiration compared to pattern without airflow under non-mulched treatment. However, the impacts of airflow are weak under mulching treatments (the gaps between including/excluding airflow modeling were within 0.1% for soil moisture, 0.1 ℃ for soil temperature and 0.1 mm d-1 for evapotranspiration). Furthermore, the effect of coupling airflow became significant when water inputs (precipitation/irrigation) were higher than 18 mm. Incorporating S-W model successfully improved evapotranspiration modeling precision, with d values increased by 0.5% and 1% for FM and FN respectively in evapotranspiration simulation, increased by 0.5%, 6.4% and 2.2% for RM, FM and FN respectively in evaporation simulation. The results here provide insights into the role of airflow in soil hydrology modeling in arid and semi-arid regions.
The 3D evolution of localised and distributed strike-slip shear zones, visualised by X-Ray CT scanning
Authors: Withers Megan , Cruden Alexander
Published: March 2020

Strike-slip systems can accommodate hundreds to thousands of kilometres of horizontal displacement by simple shear.  These systems are prone to high earthquake risk and understanding their structural geology will assist with hazard mapping and future risk mitigation. Deformation by simple shear can be concentrated on a single fault or distributed over tens to hundreds of kilometres.  It is usually challenging to understand the complex geometries that form in strike-slip systems by analysing finite strain in simple horizontal and vertical sections observed in the field.  To understand the fundamental processes that form such system, geologists use analogue experiments to test the development and evolution of structures through time.  The internal 3D evolution of deformation within analogue models of simple shear is often inferred by changes in topography and by using Particle Image Velocimetry (PIV) to analyse changes in incremental and finite strain on the model surface, similar to horizontal outcrop and map patterns, except showing the evolution of these features through time.  Cutting vertical cross sections through a simple shear experiment at specific time steps to reveal its 3D geometry is not an option when using granular materials to represent upper crustal deformation.  In this study, we use X-Ray Computed Tomography (CT) scanning to analyse the 3D evolution of strike-slip fault systems in granular materials without disruption to the analogue experiments.  We present results of the 3D evolution of localized and distributed simple shear zones by CT scanning analogue experiments at regular intervals.  Localized and distributed strike-slip shear zones are generated in an analogue shear box by using stretchable fabric to adjust the basal boundary conditions.    The results are compared to the Marlborough Fault System; a system of strike-slip faults that form the Australian – Pacific plate boundary in northeast South Island, New Zealand. 

 
Simulation of Loess Gully Evolution Based on Geographic Cellular Automata
Authors: Luo Lanhua , Li Fayuan
Published: March 2020

Gully development is an important topic in the evolution of modern geomorphology. The study of the development process of gullies is key to explain the genesis, mechanism and spatial differentiation of loess geomorphology. Geographic cellular automata (Geo-CA) can simulate complex geographical phenomena by expanding and elements of Cellular automata (CA). This study explores the mechanism of the development process of loess gullies while taking into account the dynamic factors of head-cut erosion. Based on geographic cellular automata (Geo-CA), the transition rules for gully evolution are designed, including the rules of gully head region, the rules of water infiltration, flow direction rule, flow rules, and sediment transport rules. Based on the small simulated Loess watershed under artificial rainfall, the simulation model of loess gully evolution is constructed and implemented. In order to evaluate the accuracy of the simulation results, the negative terrain, Hypsometric Integral (HI) and a gully head confusion matrix of the simulated results and the measured data are compared. The evaluation produces encouraging results in terms of numeric accuracy and spatial distribution, in agreement with the evolution of the loess gully. In addition, the simulation model of loess gully evolution this study proposed is applied to the evolution of a natural watershed, the Madigou watershed located in Jingbian County, Yulin City, Shaanxi Province. The comparison between the simulated results of the model and the measured data is used to verify the validity of the model. All the results show that the evolution model of loess gully based on Geo-CA is satisfactory in simulating the process of loess gully evolution, which provides a new research method and ideas for in-depth study of the process of gully evolution. 
Microphysics-Based Bulk Parameterizations of Enthalpy and Momentum Fluxes for Tropical Cyclones
Authors: Sroka Sydney , Emanuel Kerry
Published: March 2020

Despite the powerful influence that sea spray has on air-sea enthalpy and momentum fluxes, most state-of-the-art tropical cyclone forecast models do not incorporate the microphysics of sea spray evaporation into their boundary layer flux schemes. Since the air-sea enthalpy and momentum fluxes control a tropical cyclone’s intensification rate, increasing the accuracy of the associated bulk parameterizations is crucially important for improving forecast skill. New microphysics-based bulk parameterizations for enthalpy and momentum flux through the tropical cyclone boundary layer are developed from a set of prognostic evaporation equations and numerical simulations of evaporating, multiphase flow subject to extreme wind speeds. The microphysics-based parameterizations are computationally inexpensive and are functions of the local environmental conditions; these features allow forecast models to efficiently vary the air-sea enthalpy and momentum fluxes in space and time. By developing microphysics-based bulk parameterizations, the influence that sea spray exerts on tropical cyclone intensification can be more accurately simulated and intensity forecasts could be improved.
A Deep Learning Method for Short-Range Point Forecasts of Wind Speed
Authors: Papazek Petrina , Schicker Irene
Published: March 2020

In this study, we present a deep learning-based method to provide short-range point-forecasts (1-2 days ahead) of the 10-meter wind speed for complex terrain. Gridded data with different horizontal resolutions from numeric weather prediction (NWP) models, gridded observations, and point data are used. An artificial neural network (ANN), able to process several differently structured inputs simultaneously, is developed.
The heterogeneous structure of inputs is targeted by the ANN by combining convolutional, long-short-term-memory (LSTM), fully connected (FC) layers, and others within a common network. Convolutional layers efficiently solve image processing tasks, however, they are applicable to any gridded data source. An LSTM layer models recurrent steps in the ANN and is, thus, useful for time-series, such as meteorological observations. Further key objectives of this research are to consider different spatial and temporal resolutions and different topographic characteristics of the selected sites.

Data from the Austrian TAWES system (Teilautomatische Wetterstationen, meteorological observations in 10-minute intervals), INCA's (Integrated Nowcasting through Comprehensive Analysis) gridded observation fields, and NWP data from the ECMWF IFS (European Center for Medium-Range Weather Forecast’s Integrated Forecasting System) model are used in this study. Hourly runs for 12 test locations (selected TAWES sites representing different topographic  characteristics in Austria) and different seasons are conducted.
 
The ANN’s results yield, in general, high forecast-skills (MAE=1.13 m/s, RMSE=1.72 m/s), indicating a successful learning based on the used training data. Different combinations of the number of input field grid points were investigated centering around the target sites. It is shown that a small number of ECMWF IFS grid Points (e.g.: 5x5 grid points) and a higher number of INCA grid points (e.g.: 15x15) resulted in the best performing forecasts. The different number of grid points is directly related to the models' resolution. However, keeping the nowcasting-range in mind, it is shown that adding NWP data does not increase the model performance. Thus, for nowcasting a stronger weighting towards the observations is important. Beyond the nowcasting range, the deep learning-based ANN model outperforms the more basic machine learning algorithms as well as other alternative models.
Climatological study of the Boundary-layer air Stagnation Index for China and its relationship with air pollution
Authors: Huang Qianqian , Cai Xuhui , Wang Jian , Song Yu , Zhu Tong
Published: March 2020

The Air Stagnation Index (ASI) is a vital meteorological measure of the atmosphere’s ability to dilute air pollutants. The original metric adopted by the US National Climatic Data Center (NCDC) is found to be not very suitable for China, because the decoupling between the upper and lower atmospheric layers results in a weak link between the near-surface air pollution and upper-air wind speed. Therefore, a new threshold for the ASI–Boundary-layer air Stagnation Index (BSI) is proposed, consisting of daily maximal ventilation in the atmospheric boundary layer, precipitation, and real latent instability. In the present study, the climatological features of the BSI are investigated. It shows that the spatial distribution of the BSI is similar to the ASI; that is, annual mean stagnations occur most often in the northwestern and southwestern basins, i.e., the Xinjiang and Sichuan basins (more than 180 days), and least over plateaus, i.e., the Qinghai–Tibet and Yunnan plateaus (less than 40 days). However, the seasonal cycle of the BSI is changed. Stagnation days under the new metric are observed to be maximal in winter and minimal in summer, which is positively correlated with the air pollution index (API) during 2000–2012. The correlations between the BSI and the concentration of fine particulate matter (PM2.5) during January 2013 and November to December in 2015–2017 of Beijing are also investigated. It shows that the BSI matches the day-by-day variation of PM2.5 concentration very well and is able to catch the haze episodes.
The Quantitative Analysis of Synchronized River Flood on the Global Scale Considering Multiple Flood Peaks
Authors: Islam Md Robiul , Yamazaki Dai
Published: March 2020

Flood is one of the most frequent and severe natural disasters all over the world. Among different types of floods, the compound flood has been considered as an alarming threat over the years due to climate change. River flood synchronization acts as a compound event which is mainly occurred at the downstream of the large river confluence zones. When multiple rivers become flooded at the same time, the resultant flood magnitude and flood duration at their confluences zone raise drastically. Only a few previous research addressed synchronized flood risk at a local scale, where simply yearly peak synchronization has been considered to avoid the complexity of detecting multiple peaks. However, several rivers occasionally show significant multiple peaks in a single year and sometimes yearly peak stays much below the flood limit.  Therefore, the existing technique either over-estimate or under-estimate synchronized flood risk, apparently, it is not applicable at the global scale.

The quantitative analysis of synchronized flood at a global scale considering multiple peaks is still a big challenge. Here, we have developed a flood return period-based new methodology to quantify synchronous flood precisely as well as to detect the background of the synchronous flood, either multiple peak synchronization or yearly peak synchronization. To find out the suitable confluence points on the global scale, we set two conditions. Firstly, the drainage area of contributing rivers is large enough to become different hydrological features and secondly, both rivers contribute a significant amount of discharge for the generation of flood at the respective confluence points. The next-generation global river routing model, CaMa-Flood, has been employed to compute discharge for return period-based analysis of selected rivers and confluence points. Finally, we check the contributing rivers return period discharge when the respective confluence point is at flooded condition, and if both rivers exceed corresponding 2-year return period discharge, those events are considered as synchronized floods.

We have found 53 confluence points on the global scale where catastrophic flood hazards may occur due to flood synchronization. The historical floods in 49 confluence points show different degrees of synchronization. Moreover, the Confluence zone flood at high latitude mostly affected by yearly peak synchronization may be due to the snowmelt domination. In contrast, the historical synchronized floods in tropical and sub-tropical regions affected by different levels of multiple peak synchronization where rainfall timing might be playing a significant role. This method emerges the physical mechanism of the historical catastrophic fluvial flood that took place where the large rivers have merged.
Deformation microstructure of amphibole peridotite from Aheim, Norway and its implication for the seismic anisotropy of the mantle wedge
Authors: Jung Sejin , Jung Haemyeong , Austrheim Håkon
Published: March 2020

The microstructures of amphibole peridotites from the Åheim, Norway were studied to understand the evolution of microstructures of olivine through the Scandian Orogeny and the subsequent exhumation process. The Western Gneiss Region, Norway had undergone UHP metamorphism and subsequent retrogression associated with the Scandian Orogeny. The Åheim amphibole peridotite shows clear porphyroclastic texture, abundant hydrous minerals such as tremolite or chlorite, and much evidence of localized deformation. LPOs of olivine and amphibole were determined by using electron back-scattered diffraction (EBSD) system attached to the scanning electron microscope (SEM).

Detailed microstructural analysis on the Åheim amphibole peridotites revealed the evidence of the multiple stages of deformation during the Scandian Orogeny. The coarse grains of olivine including porphyroclasts showed the A-type LPO of olivine (Jung & Karato, 2001), which is interpreted as an initial stage of deformation. The recrystallized-fine grains of olivine showed the B-type LPO of olivine (Jung & Karato, 2001), which is interpreted as a late-stage deformation in amphibolite facies condition. Observation of abundant hydrous minerals, hydrous inclusions in olivine, as well as high dislocation density of olivine in the fine-grained olivines suggest that fabric transition of olivine from the A-type to B-type LPO was resulted from the deformation in a water-rich condition during the exhumation process. The B-type LPO of olivine is important because it is the one of the possible mechanisms for causing the trench-parallel seismic anisotropy in the mantle wedge. A partial fabric transition from the A-type to the B-type LPO of olivine associated with the localized deformation in a water-rich condition might explain a weak seismic anisotropy observed in NE Japan or Mexico. Amphiboles in the amphibole-rich layer showed the Type-III LPO of amphibole (Ko & Jung, 2015). It is found that strong fabric strength and the resultant seismic anisotropy of amphibole can perform a similar role as other hydrous minerals such as serpentine or chlorite on the trench-parallel seismic anisotropy with the flow dipping along the subducting slab in the mantle wedge.

 

Jung, H., Karato, S., 2001, Science, 293, 1460-1463.

Ko, B., Jung, H., 2015, Nature Communications, 6: 6586.
From Monitoring to Forecasting the Land Surface Condition Using a Land Data Assimilation System: Application over the Contiguous United States
Authors: Mucia Anthony , Albergel Clément , Bonan Bertrand , Zheng Yongjun , Calvet Jean-Christophe
Published: March 2020

LDAS-Monde is a global Land Data Assimilation System developed in the research department of Météo-France (CNRM) to monitor Land Surface Variables (LSVs) at various scales, from regional to global. With LDAS-Monde, it is possible to assimilate satellite derived observations of Surface Soil Moisture (SSM) and Leaf Area Index (LAI) e.g. from the Copernicus Global Land Service (CGLS). It is an offline system normally driven by atmospheric reanalyses such as ECMWF ERA5.

In this study we investigate LDAS-Monde ability to use atmospheric forecasts to predict LSV states up to weeks in advance. In addition to the accuracy of the forecast predictions, the impact of the initialization on the LSVs forecast is addressed. To perform this study, LDAS-Monde is forced by a fifteen-day forecast from ECMWF for the 2017-2018 period over the Contiguous United States (CONUS) at 0.2o x 0.2o spatial resolution. These LSVs forecasts are initialized either by the model alone (LDAS-Monde open-loop, no assimilation, Fc_ol) or by the analysis (assimilation of SSM and LAI, Fc_an). These two sets of forecast are then assessed using satellite derived observations of SSM and LAI, evapotranspiration estimates, as well as in situ measurements of soil moisture from the U.S. Climate Reference Network (USCRN). Results indicate that for the three evaluation variables (SSM, LAI, and evapotranspiration), LDAS-Monde provides reasonably accurate predictions two weeks in advance. Additionally, the initial conditions are shown to make a positive impact with respect to LAI, evapotranspiration, and deeper layers of soil moisture when using Fc_an. Moreover, this impact persists in time, particularly for vegetation related variables. Other model variables (such as runoff and drainage) are also affected by the initial conditions. Future work will focus on the transfer of this predictive information from a research to stakeholder tool.
Drivers of long-term and short-term Nitrogen concentrations and runoff dynamics in a forested karst catchment
Authors: Dirnböck Thomas , Brielmann Heike , Kobler Johannes , Hartmann Andreas
Published: March 2020

Excess Nitrogen (N) deposition from industrial, domestic and agricultural sources has led to increased nitrate leaching, increased gaseous N emissions, the loss of biological diversity, and has affected C sequestration in forest ecosystems. Nitrate leaching affects the purity of karst water resources, which contribute around 50 % to Austria’s drinking water supply. Here we present the first comprehensive evaluation of a 26 years record of dissolved inorganic N (DIN) concentrations and fluxes from a karst catchment in the Austrian Alps (LTER Zöbelboden), which was not affected by local N sources but solely by long-range N deposition (20-25 kg N ha-1 y-1 total N deposition). We inferred from soil chemical and microbial data as well as nitrate leaching, that the forest ecosystems in the catchment are likely saturated with respect to nitrogen. Consequently, 60-70% of the atmospheric N input was lost via leaching of NO3- to the karst aquifer or emission of N2O to the atmosphere. However, due to high dilution DIN concentrations in the runoff rarely exceed 2 mg N l-1. An exception were periods of forest disturbances. A number of strong storms (2007-2008) caused some major windthrows as well as single tree damages (5-10% of the catchment). Runoff concentrations of DIN showed clear responses to the disturbances with an increase (~ 1 mg N l-1) until 2008/09 and a decreased again in 2010/11 to pre-disturbance levels. Apart from disturbances, drought years led to an increase in NO3- in the soil water in the following years. We observed the subsequent changes of the dynamics of DIN in runoff with a high-resolution water probe during 2018 and 2019. This data shows that the severity of the drought and the magnitude of the first rewetting event after a period of drought drives the size of the flush of DIN. It is likely that N deposition will lower with legislated emission reductions and that the currently N leaky ecosystems may immobilize more N when climate is becoming warmer in the future. However, we hypothesize that the karst aquifer will still receive DIN rich runoff water due to long-term lags in the recovery of a closed N cycle and because of expected climate events such as storms and droughts.
The Value of Drones for Bespoke Local Flood Risk Assessment in the Licungo Basin
Authors: Manalili Michael Andrew , Schumann Guy , Prades Lara , Rosa Sophia , Reane Domingos , Beleza Antonio Jose
Published: March 2020

Floods and their impacts are highly local in nature and vulnerable population and exposed assets are most at risk in coastal monsoonal regions. This is aggravated if the region is also exposed to tropical cyclones, such as Mozambique and the Licungo basin along the eastern coastline of the country.

In order to be better prepared against future high-impact flood events, Mozambique’s National Institute for Disaster Management (INGC) has mapped the watershed of the country’s central Licungo River with drones to reduce flood risks and improve emergency response planning. The mapping is intended to “minimize risks” and promote timely preparation of actions when cyclones and floods are expected in the area.

In the proposed project, the acquired drone terrain model and collected field data (water levels) will be used to drive a bespoke localized 2-D flood model to accurately reproduce flood hazard and risk in the central Licungo basin for the 2013 and 2015 flood disasters. In addition, high-resolution population and exposure layers have been used to define bespoke local flood risk maps.

Accurate flood risk assessment of past events at the local scale can better inform decision support systems and facilitate the decision-making process and preparedness for future high-impact events. Knowing who is at risk where and when is vital information that is missing in many vulnerable regions and is most of the time not available at the required local level.

Moreover, global or large-scale flood prediction models do not contain the necessary detail to infer meaningful flood risk at the local level and such models are known to be inaccurate, albeit they represent best efforts at the scales they are simulating. However, to what degree these models are wrong at the local scale of impact and what is needed to improve them is not known, largely because local flood data and bespoke predictions of flood risk are missing at the local scale for many vulnerable regions. The collected high-resolution data and the local flood risk assessment this project proposes would allow the validation of large-scale modeling efforts thereby advancing our understanding of model limitations and would create opportunities to improve them at large scales.
Chemical and Isotopic Composition Measurements on Atmospheric Probes for Giant Planets
Authors: Wurz Peter , Vorburger Audrey , Waite Hunter , Mousis Olivier
Published: March 2020

The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Unfortunately, no designated mission to either of the two ice giants exists so far. Almost all of our gathered information on these planets comes from remote sensing. Whereas information provided by remote sensing is undoubtedly highly valuable, remote sensing of a planet's atmosphere also has limitations. In recent years, NASA and ESA have started planing for future missions to Uranus and Neptune, with both agencies focusing their attention on orbiters and atmospheric probes. A mass spectrometer experiment is a favored science instrument for an atmospheric probe for in situ composition measurements in most of these studies. Mass spectrometric measurements can provide unique scientific data, i.e., sensitive and quantitative measurements of the chemical composition of the atmosphere, including isotopic, elemental, and molecular abundances. Of major interest for the formation and evolution process of our Solar System are the species including the major volatiles CH4, CO, NH3, N2; the noble gases He, Ne, Ar, Kr, Xe; and the isotopic ratios D/H,13C/12C, 15N/14N, 3He/4He, 20Ne/22Ne, 38Ar/36Ar, 36Ar/40Ar, as well as those of Kr and Xe. We will review the state-of-the-art mass spectrometry with respect to an application on such an atmospheric probe.  
Understanding Aerosol Vertical Transport During Heavy Aerosol Pollution Episodes in the North China
Authors: Yuan Renmin
Published: March 2020

Due to excessive anthropogenic emissions, heavy aerosol pollution episodes (HPEs) often occur during winter in the Beijing-Tianjin-Hebei (BTH) area of the North China Plain. Extensive observational studies have been carried out to understand the causes of HPEs; however, few measurements of vertical aerosol fluxes exist, despite them being the key to understanding vertical aerosol mixing, specifically during weak turbulence stages in HPEs. In the winter of 2016 and the spring of 2017 aerosol vertical mass fluxes were measured by combining large aperture scintillometer (LAS) observations, surface PM2.5 and PM10 mass concentrations, and meteorological observations, including temperature, relative humidity (RH), and visibility, at a rural site in Gucheng (GC), Hebei Province, and an urban site at the Chinese Academy of Meteorological Sciences (CAMS) in Beijing located 100 km to the northeast. These are based on the light propagation theory and surface-layer similarity theory. The near-ground aerosol mass flux was generally lower in winter than in spring and weaker in rural GC than in urban Beijing. This finding provides direct observational evidence for a weakened turbulence intensity and low vertical aerosol fluxes in winter and polluted areas such as GC. The HPEs included a transport stage (TS), an accumulative stage (AS), and a removal stage (RS). During the HPEs from 25 January 2017 to January 31, 2017, in Beijing, the mean mass flux decreased by 51% from 0.0049 mg m-2s-1 in RSs to 0.0024 mg m-2s-1 in the TSs. During the ASs, the mean mass flux decreased further to 0.00087 mg m-2s-1, accounting for approximately 1/3 of the flux in the TSs. A similar reduction from the TSs to ASs was observed in the HPE from 16 December 2016 to 22 December 2016 in GC. It can be seen that from the TS to the AS, the aerosol vertical turbulent flux decreased, but the aerosol particle concentration within surface layer increased, and it is inferred that in addition to the contribution of regional transport from upwind areas during the TS, suppression of vertical turbulence mixing confining aerosols to a shallow boundary layer increased accumulation.
A novel method for directly obtaining the water vapor isotope surface flux for evaluating snow-atmosphere exchange processes
Authors: Wahl Sonja , Steen-Larsen Hans Christian , Zuhr Alexandra , Reuder Joachim
Published: March 2020

Water isotopologues offers a direct constraint on the physical processes controlling surface fluxes.  A novel method is presented which enables in-situ measurements of the water vapour isotope flux between the snow surface of the Greenland Ice Sheet and the atmosphere.

These observations have become possible by combining a cavity ring-down laser absorption spectroscopy analyzer with high frequency latent heat flux eddy-covariance measurements.

This new method reveals an isotope flux driven by the diurnal cycle.
Water isotopes can thus act as a natural tracer giving information of the physical processes such as the influence of turbulent fluxes in the water cycle. This allows the assessment of sublimation and deposition processes in the low accumulation zone of the interior Greenland Ice Sheet.
Therefore, we can provide a strategy to benchmark the parameterizations of surface mass balance and surface fluxes in regional climate models.
Infrared limb sounding of cirrus clouds: state of knowledge, recent progress, and future prospects
Authors: Spang Reinhold , Bartolome Irene , Ungermann Jörn , Griessbach Sabine , Hoffmann Lars , Krämer Martina , Höpfner Michael , Dinelli Binaca , Maestri Tiziano , Siddans Richard , Müller Rolf , Riese Martin
Published: March 2020

Cirrus clouds are the highest altitude clouds in the troposphere and play an important role in the climate system. They can either have a cooling or heating effect in radiation balance around of the planet, depending on which altitude and temperature they appear. Despite the importance of this type of clouds for the radiation budget there are still big gaps of knowledge regarding their micro and macro physical properties (e.g. particle sizes, ice water content, occurrence and coverage at the upper troposphere and lower stratosphere), especially for optically very thin cirrus in the tropopause region, which are difficult to detect even for active lidar measurements. Due to the long path length through the atmosphere and good vertical resolution passive infrared limb measurements are especially well suited to observe this type of clouds. The presentation will highlight the current status in infrared limb sounding and corresponding particle parameter retrievals with respect to recent and future space and airborne sensors (e.g. CRISTA, MIPAS, and IR limb-imaging instruments).
Chemical complexity matters: differential mobilization of mineral-associated organic matter driven by functionally distinct rhizodeposits
Authors: Bölscher Tobias , Li Hui , Garcia Arredondo Mariela , Cardon Zoe G. , Malmstrom Carolyn M. , Winnick Matthew , Keiluweit Marco
Published: March 2020

Protective mineral-organic associations are the quantitatively most important soil carbon storage mechanism, but their vulnerability to environmental change is largely uncertain. While it is well established that root growth can promote (or “prime”) the microbial decomposition of organic matter (OM), our mechanistic knowledge of the ability of roots to destabilize OM protected within mineral-organic associations remains limited. Here we examined how the composition of root-derived compounds (rhizodeposits) affects the stability of mineral-organic associations.

In model systems, we first tested the ability of functionally distinct low-molecular weight compounds (ligands, reductants, simple sugars) commonly observed in the rhizosphere to cause the mobilization and mineralization of isotopically labeled OM from different mineral types (Fe and Al hydroxides). Our results showed that all compounds stimulated mobilization and mineralization of previously mineral-associated OM. However, OM bound to Al hydroxide was less susceptible to mobilization than OM bound to Fe hydroxide. Further, sugars and reductants revealed a greater mobilization potential than ligands for both mineral types, suggesting that OM mobilization in soils may be microbially mediated, rather than driven by direct mineral dissolution. In complementary pot experiments, we investigated the effect of rhizodeposition on the mobilization of mineral-associated OM. We grew Avena sativa in soils amended with isotopically-labeled mineral-organic associations and followed mobilization dynamics over four weeks. First results indicated that rhizodeposition dynamics dictate the mobilization and mineralization of mineral-associated OM. Together, our results suggest a strong mechanistic linkage between the composition and functionality of rhizodeposits and their ability to destabilize mineral-associated OM.
Underestimation of temperature variability in weather generators and implications for the representation of extreme temperatures in downscaled climate change scenarios
Authors: Calanca Pierluigi
Published: March 2020

Stochastic weather generators are still widely used for downscaling climate change scenarios, in particular in the context of agricultural and hydrological impact assessments. Their performance is in many respects satisfactory, except perhaps for the fact that they fail to represent climatic variability in an adequate way. This has implications for the representation of extreme values and their statistics. Concerning precipitation, different approaches for amending this situation have proposed in the past, including using more sophisticated models to better simulate the persistence of wet and dry spells, conditioning rainfall-generating parameters on indices of the large-scale atmospheric circulation, or employing autoregressive models to represent year-to-year variations in annual precipitation amounts. With regard to (minimum and maximum) temperature, efforts to address the question of why weather generators underestimate total variability have been less systematic. Based on results obtained with a well-known weather generator (LARS-WG), this contribution aims to discuss which modes of variability are missing and why, elaborate on the implications of underrepresenting temperature variance for the simulation of temperature extremes in downscaled climate change scenarios, and suggest options to tackle the problem and improve the model performance.
Effects of urbanization on food-energy-water systems in mega-urban regions: a case study of the Bohai MUR, China
Authors: Deng Caiyun , Wang Hongrui , Gong Shuxin , Zhang Jie , Yang Bo , Zhao Ziyang
Published: March 2020

The security of food-energy-water systems (FEW systems) is an issue of worldwide concern, especially in mega-urban regions (MURs) with high-density populations, industries and carbon emissions. To better understand the hidden linkages between urbanization and FEW systems, the pressure on FEW systems is quantified in a typical rapid urbanizing region—the Bohai MUR. The correlation between urbanization indicators and the pressure on FEW systems is analyzed and the mechanism of the impact of urbanization on FEW systems is further investigated. Results show that approximately 23% of croplands is lost, 61% of which is converted to construction lands and the urban areas expand by 132.2% in the Bohai MUR during 1980-2015. The pressure on FEW systems has an upward trend with the stress index of the pressure on FEW systems (FEW_SI) exhibiting ranging from 80.49 to 134.82% and dominant pressure consisting of that has converted from water system pressure to energy system pressure since 2004. The FEW_SI in the Bohai MUR is enhanced with cropland loss and the increase in urbanization indicators. Additionally, land use, populations, incomes, policies and innovation are the main ways urbanization impacted FEW systems in MURs. This study enhances our understanding of the pressure variation on FEW systems in MURs and the effects of urbanization on FEW systems, which helps stakeholders to enhance the resilience of FEW systems and promote sustainable regional development.

Keywords: urbanization, food-energy-water system pressure, linkages, MURs
Impact of November 2010 volcanic activity on the UTLS temperatures
Authors: Lasota Elżbieta , Biondi Riccardo , Ladstädter Florian , Steiner Andrea K.
Published: March 2020

Recent studies have shown an increase of stratospheric aerosol optical depth in the last 20 years despite the absence of large volcanic eruptions in the same period, contributing to supporting the hypothesis that several minor eruptions could impact the atmospheric variability as a large one. November 2010 was a relatively active volcanic period in the tropical belt, three eruptions with Volcanic Explosivity Index higher than 3 occurred in a time span of about 3 weeks: Merapi, Tengger Caldera and Tungurahua. Merapi was the largest eruption of the three, directly overshooting the stratosphere and injecting a large amount of sulfur dioxide. In this study, we analyse the impact of this series of eruptions on the temperature derived from radio occultation observations in upper troposphere lower stratosphere at the local, regional and global scale. The impact of the Quasiâ€Biennial Oscillation, El Niño–Southern Oscillation, and linear trend on temperature is estimated and removed from temperature time series using multiple linear regression. Signatures of volcanic eruptions in temperature are analysed using post fit residuals. The results show significant warming in the lower stratosphere between 10°S and 0° for a period of 7 months after the eruptions with a maximum anomaly amplitude of about 1.4 K at 18 km altitude. Whilst the maximum warming in Merapi’s vicinity occurred 4 months after the eruption and reached the magnitude of almost 4 K.
Structural Characteristics and Mechanism of the Horsetail Structure in China Offshore Basins: Case Studies from Liaodong Bay Area, Bohai Bay Basin and Weixinan Area, Beibuwan Basin
Authors: Zhang Jie , Wu Zhiping , Cheng Yanjun
Published: March 2020

The horsetail structure, also named brush structure, generally refers to a sets of secondary faults converged to the primary fault on the plane. Based on 2-D and 3-D seismic data, the structural characteristics, evolution and mechanism of the horsetail structure of Liaodong Bay area in Bohai Bay Basin and Weixinan area in Beibuwan Basin are analyzed. In the Liaodong Bay area, the primary fault of the horsetail structure is the NNE-striking branch fault of Tan-Lu strike-slip fault zone. The NE-striking secondary extensional faults converged to the primary strike-slip fault. Fault activity analysis shows that both the primary and secondary faults intensively activated during the third Member of the Shahejie Formation (42~38 Ma). In the Weixinan area, the NE-striking Weixinan fault is the primary fault of the horsetail structure, which is an extensional fault. A large amount of EW-striking secondary extensional faults converged to the primary NE-striking Weixinan fault. Fault activity analysis shows that NE-striking primary fault intensively activated during the second Member of the Liushagang Formation (48.6~40.4 Ma), whereas the EW-striking secondary faults intensively activated during the Weizhou Formation (33.9~23 Ma). The different structure and evolution of the horsetail structure in the Liaodong Bay area and Weixinan area are mainly resulted from the regional tectonic settings. About 42 Ma, the change of subduction direction of the Pacific plate and the India-Eurasian collision resulted in the right-lateral strike-slip movement of NNE-striking Tan-Lu fault and the formation of NE-striking extensional faults along the bend of the strike-slip fault, therefore, the horsetail structure of Liaodong Bay area formed. However, the formation of the horsetail structure of Weixinan area is related to the clockwise rotation of extension stress in the South China Sea (SCS): 1) During Paleocene to M. Eocene (65~37.8 Ma), the retreat of Pacific plate subduction zone resulted in the formation of NW-SE extensional stress field in the north margin of the SCS, NE-striking primary fault of horsetail structure formed; 2) During L. Eocene to E. Oligocene (37.8~28.4 Ma), the change of subduction direction of the Pacific plate and the India-Eurasian collision resulted in the clockwise rotation of extension direction from NW-SE to N-S in the north margin of the SCS, a large amount of EW-striking secondary faults of horsetail structure formed, and the horsetail structure was totally formed in the Weixinan area until this stage.