bluuebunny/crossref_metadata_2025 huggingface dataset:
Large scale high resolution modelling of the West African rivers and aquifers
Authors: Depeyre Alban , Cohard Jean-Martial , Hector Basile , Maxwell Reed , Pellarin Thierry
Published: March 2020

West Africa has been classified as one of the most vulnerable regions in the world for water resources to face global changes, both climatic and demographic. The population is expected to double by 2050 leading to increased pressure on the use of water resources. In this context, it is necessary to understand the dynamics of major African hydrosystems as large rivers (Niger river, Senegal river...) and transboundary aquifers in order to predict the fate of water resources for the next decades. The ParFlow-CLM physical-based model was chosen for its ability to simulate surface water and groundwater dynamics in a coupled manner. This type of modelling makes it possible to represent the main hydrological processes observed over the whole West Africa region. It operates at a relatively fine spatial resolution (1 km²). The main challenge is to determine the hydrodynamic parameters of the soil for the entire region and on a 100 m thickness (i.e. 3.5 million pixels times 11 layers).

As a first step, the model was implemented on two catchments monitored by the AMMA-CATCH observatory. These two watersheds are representative of the major and contrasted processes found in WA : being respectively representative of Sudanian and Sahelian climates. In order to assess the relevance of the regional databases (SoilGrids and GLHYMPS), simulations were carried out with original and adjusted (based on observations) soil parameters and results were evaluated with local measurements. It appears that the deep weathered lithology is not considered in databases for most of hard-rock areas in intertropical areas with no tectonic uplift. Aquifer thicknesses, permeabilities and porosities have to be significantly enhanced for the model to represent the correct flow paths. Furthermore, in the Sahel where most of the annual precipitation falls during a dozen events only, a crust layer (consistent with observations) has been added to represent the large runoff coefficients which lead to the early season floods.

In a second step, the model was implemented at the West Africa scale using the adjusted soil parameters. These parameters were obtained using a simple linear law that have been applied uniformly over the entire domain and a mask over a part of the Sahel representative of the crusting zones. Results will be compared with both remotely sensed and in situ data : GRACE provides water stock variations at a very large scale, MERRA and ERA reanalysis provide evapotranspiration data. Altimeters and in situ measurements provide river flow data. In the near future the launch of the SWOT satellite will bring new observations to complete the current one. The evaluation of the different compartments of the hydrological cycle should reveal spatial discrepancies in the model's ability to represent processes, highlighting the points on which further work should focus.
No risk - no fun: The tradeoff between avoiding frost and maximizing growth
Authors: Baumgarten Frederik , Vitasse Yann , Gessler Arthur
Published: March 2020

Abstract

Leaf-out timing is crucial for the fitness of deciduous trees inhabiting temperate and higher latitudes. Optimal leaf-out allows minimizing freezing damages and herbivory pressure while maximizing growing season length and resource uptake in order to increase their competitiveness. However only a few attempts have been made to classify species according to their strategy along this trade-off.

Using climate chambers, we artificially provoked 5 different flushing dates that span the maximum possible range of natural occurring flushing dates of 4 tree species (Prunus avium, Carpinus betulus, Fagus sylvatica and Quercus robur). Shortly after each of the five leaf-out timings, 12 saplings per species were exposed to a frost treatment that is expected to either kill all leaves (LT100, i.e. lethal temperature killing 100% of the leaves) or to partially damage them. These temperature thresholds have been adapted to each species according to their freezing resistance found in the literature. A subset of 12 indviduals per species served as a control and were not subjected to a frost treatment. Shortly after the frost treatment, all saplings were planted outside in the ground under a shading net (~-60% of light transmission) simulating below canopy conditions at the WSL research facility near Zürich.

Growth parameters (diameter, height) and recovery state (percentage of greenness compared to the control) were regularly measured during the consecutive growing season as well as the leaf coloring in autumn 2019. Preliminary results suggest that cherry and oak have recovered more than 80% by the end of the growing season, whereas beech and hornbeam only recovered about 50%. Oak was the fastest species to recover, already reaching 80% three weeks after the frost treatment. Our results allow to better quantify to what extend damaging spring frost reduces competitiveness for resources (light, nutrients) among species.
Detrital mineral composition and provenance of the Camp Century basal ice sediments
Authors: Thomsen Tonny B. , Knutz Paul C. , Fosdick Julie C. , Hemming Sidney R. , Christ Andrew , Bierman Paul R. , Perdrial Nico , Hughes John , Schaefer Joerg , Tison Jean-Louis , Blard Pierre-Henri , Protin Marie , Dahl-Jensen Dorthe , Steffensen Jørgen P.
Published: March 2020

The Camp Century Ice core, NW Greenland, recovered a 4.5 m basal section consisting of frozen sediments and debris-rich ice. This material was recently re-discovered in Danish ice core storage and visually logged. As part of a multi-disciplinary effort to unlock the climatic and paleo-environmental signal of this unique record, we have analysed detrital mineral composition and metamorphic ages. Bulk mineral analyses were performed at the Geological Survey of Denmark and Greenland on grain mounts from 2 core intervals using a SEM automated quantitative mineralogy (AQM) approach coupled to laser ablation ICP-MS analyses. This setup allows us to gain a full mineral description together with single-grain U-Pb dates for a large population of metamorphic components, e.g. apatite, rutile, titanite and zircon. In addition, amphibole grains were picked for 40Ar-39Ar dating performed at the LDEO Argon Isotope Lab. Mineralogical characterization was completed by X-Ray diffraction analysis of the fine fraction to determine the presence and nature of potential clay weathering products, and single-crystal X-ray diffraction was utilized to characterize the atomic arrangements of minerals that occur in solid solutions. The AQM results indicate that metamorphic minerals are present in sufficient amounts (100’s) for gaining statistically valid provenance data. Preliminary results show ages in the 1900 – 1700 Ma range (amphibole, rutile) and around 2700 Ma (zircon). This, along with the presence of swelling clays in the sediments, is consistent with weathering of the local bedrock, and/or sediments transported from the Inglefield orogenic belt north of the site. To gain information on the youngest thermal events of sediment sources, potentially revealing deep glacial incision, (U-Th-Sm)/He dating of single apatite grains is underway. Preliminary work on the 125-250 µm size fraction yield abundant subhedral-to-subrounded, euhedral apatite suitable for thermochronology. Here we report the results from the different methods and discuss the implications for understanding erosional processes and potential transport pathways of the Camp Century basal ice sediments. 
Seasonal-to-multiyear prediction of ENSO using machine deep learning
Authors: Luo Jing-Jia , Ling Fenghua , Ham Yoo-Geun , Kim Jeong-Hwan
Published: March 2020

Variations in the El Niño/Southern Oscillation (ENSO) are associated with a wide array of regional climate extremes and ecosystem impacts. Robust, long-lead forecasts would therefore be valuable for managing policy responses. But despite decades of effort, forecasting ENSO events at lead times of more than one year remains problematic. Here we show that a statistical forecast model employing a deep-learning approach produces skilful ENSO forecasts for lead times of up to one and a half years. To circumvent the limited amount of observation data, we use transfer learning to train a convolutional neural network (CNN) first on historical simulations and subsequently on reanalysis from 1871 to 1973. During the validation period from 1984 to 2017, the all-season correlation skill of the Nino3.4 index of the CNN model is much higher than those of current state-of-the-art dynamical forecast systems. The CNN model is also better at predicting the detailed zonal distribution of sea surface temperatures, overcoming a weakness of dynamical forecast models. A heat map analysis indicates that the CNN model predicts ENSO events using physically reasonable precursors. The CNN model is thus a powerful tool for both the prediction of ENSO events and for the analysis of their associated complex mechanisms.
The role of formal institutions in forest decline: exploring institutional failure
Authors: Yates Jim , Secco Laura , Carbone Francesco
Published: March 2020

Recent global efforts to reduce and abate forest declines i.e. deforestation, degradation and disturbance, forest ecosystems are extensive and well incentivised. Forests, however, remain as areas subject to competing resource objectives with complex socio-economic development paradigms and historical policy narratives. Indirect and direct causes forest decline are well cited across the literature. The concept that institutions are failing to secure positive outcomes for forest resources, however, is a somewhat new concept in resource management discourses. It is argued that formal institutions in forest management acting as developers, intermediaries, and the regulators of forest policy, having legitimized competency, are subject to meso-scale failure and in some circumstances contribute to forest decline. Adopting a mixed-method approach, application of a modified DPSIR framework, DPAESMR (Drivers-Policy-Actions-Effects-State Changes-Monitoring and Reporting) was combined with elements from the traditional policy cycle logic to develop a novel policy evaluation analysis tool or PEA. Using the PEA, analysis of classical literature and empirical experiences across four separate international and geographical case studies focused on formal institutions in forest management, their forest policy, actions and effects and are assessed against more recently reported state changes to respective forest resources, along with gaps in subsequent monitoring and reporting efforts. The analysis highlights land-use change and forest exploitation, intentional or not, demonstrates sustained losses in forest area, degradation processes and forest disturbance despite established/legitimized forest policy and robust formal intuitional direction and support. Forest policy interpreted and derived from acts, laws and norms vary across all cases naturally, although, similar themes such as gaps in institutional regulation, enforcement and information, subsequently result in weak forest administration. Evidence of robust, reasonably well covered and incentivized formal forest institutions exist irrespaective of forest administrative area and have failed to address forest decline and is highlighted as meso-scale failure or institutional failure. Understanding traditional issues such as property rights, path-dependence or re-orientation may succeed in strengthening institutional adaptation to triggers, crises and abrupt policy changes which will aid the effort in slowing forest decline.

Keywords

Forest decline, Institutional failure, DPSIR, forest management, policy analysis
Groundwater flow at the Rock Garden test site
Authors: Englert Andreas , Gossel Wolfgang , Bayer Peter
Published: March 2020

Understanding of subsurface flow and transport is of major interest supporting optimal design for several societal relevant technologies, such as waste disposals, geothermal or groundwater production facilities. To advance measurement and modeling techniques and refine them for practical applications, we develop the fractured aquifer test site Rock Garden at the Martin-Luther University Halle.

 

The Rock Garden test site is situated beneath the courtyard of the Faculty of Natural Sciences III and is 60 m x 60 m in size. Fractured Rotliegend series of konglomerates, sand- and siltstones are investigated at the site by 6 drillings. A central borehole (B3) is 40 m in depth and developed as an open borehole between 15 m – 40 m below surface. Five boreholes are developed as groundwater observation wells of about 20 m depth and are equipped with filterscreens between 10 m - 20 m below surface. Natural groundwater levels are on average about 3 m below surface and vary about 0,5 m around this value.

 

A first pumping test in B3 unraveled hydraulic connection to all of the five surrounding boreholes. The effective transmissivities are of the order of 10-5 m2/s and storativities are of the order 10-3. To understand hydraulically active fractures or fracture zones and their connection to the rock matrix at the Rock Garden site, we plan to performed a first flowmeter experiment in well B3 under natural and pumping conditions. Finally we plan to characterize these fractured zones in detail performing hydraulic and tracer tomography at the Rock Garden test site in the near future.
The Influence of Anthropogenic Aerosols on the Aleutian Low
Authors: Dow William , Maycock Amanda , Lofverstrom Marcus
Published: March 2020

There is an incomplete understanding of the mechanisms that govern the Pacific Decadal Oscillation (PDO), a major mode of climate variability that plays a key role in the evolution of global climate on decadal time-scales. Recent research has suggested that regional anthropogenic aerosol (AA) emissions could modulate the behaviour of the PDO, including the transition to a negative PDO phase starting in the late 1990s (Smith et al., 2016). However, other studies have questioned whether this connection is robust (Oudar et al., 2018). East Asia is a region of particular focus, where AA emissions having increased in recent decades (Bartlett et al., 2017). Here we combine analysis of an ensemble of coupled climate models running idealised AA perturbation experiments and a steady-state primitive equation model (LUMA) forced by diabatic heating anomalies to examine whether AA emissions influence the behaviour of the Aleutian low - a climate feature closely associated with the PDO  - and if so, test the posited teleconnection mechanisms proposed by Smith et al. (2016). We further compare the response of the Aleutian low to well mixed greenhouse gases to examine if AAs and GHGs influence the Aleutian low in a similar manner.
Quasi real-time water budget analysis for hydrological drought monitoring, assessment and prediction in a highly regulated river
Authors: Kwon Hyun-Han , Kim Jang-Gyeong , Kim Jin-Guk , Jeon Geun-Il
Published: March 2020

With a highly regulated river and water distribution system, assessment of water availability under drought stress to meet the current (or future) demand and supply is becoming a challenging issue due to their complexities in the water distribution system. However, coarse spatial and temporal resolution in a general water budget analysis model may be viewed as a limitation to understanding the entire pathway for various combinations of water allocations, return flows, and dam operations. In these contexts, this study aims to develop a Daily-based quasi real-time Water Budget simulation model-Sejong University (DWB-SU) comprised of sub regions (or nodes) that are determined by water-related facilities and water permits. The proposed DWB-SU model is a flexible tool that could be applied to highly regulated river basins.

 

Acknowledgement

This research gratefully acknowledges the financial support provided by Korea Water Resources Corporation (K-water). This work was also supported by the National Research Foundation of Korea(NRF) funded by the Ministry of Education (No. 2019R1A2C2087944)
Transient characteristics of eﬀective porosity and speciﬁc yield in bedrock aquifers
Authors: Foley Aidan , Worthington Stephen , Soley Robert
Published: March 2020

Studies of bedrock aquifers have often treated eﬀective porosity and speciﬁc yield as having a similar, time-
invariant value. Here, we apply a series of tests of speciﬁc yield and eﬀective porosity at multiple temporal scales
to the carbonate Chalk aquifer of east Hampshire, England. These include analysis of natural water level, discharge and
water quality variations, numerical model calibrations, hydrograph recession analysis, pumping tests, and tracer
tests using both injected and environmental tracers. Values of both eﬀective porosity and speciﬁc yield are
shown to be transient phenomena that are dependent upon the temporal test scale, an eﬀect which results from
the dual-porosity structure of the aquifer. Over short time periods, aquifer response is dominated by preferential
ﬂow through the low-storage, high-permeability, dissolutionally-enhanced fracture network; eﬀective porosities on a timescale of hours to
days are 0.0001–0.001. Over longer time periods, aquifer response becomes increasingly dominated by the high-
storage, low-permeability matrix, with the eﬀective porosity rising to approximate total porosity (0.39) on a
timescale of decades. Speciﬁc yield also increases as a function of timescale, though there is much less variability
than with eﬀective porosity. Our ﬁndings demonstrate that it is critical to use an eﬀective porosity value ap-
propriate to the timescale when making transport calculations. Preferential ﬂow through fracture networks is
common in bedrock aquifers. Consequently, the transient nature of both eﬀective porosity and speciﬁc yield that
has been demonstrated in the Chalk aquifer is likely to be broadly representative of most bedrock aquifers.
Modelling fate and transport of pesticides: the case study of the contamination in Valencia aquifers.
Authors: Pérez Indoval Ricardo , Cassiraga Eduardo , Rodrigo-Ilarri Javier
Published: March 2020

Predicting the fate of pesticides released into the natural environment is necessary to anticipate and minimize adverse effects far from the contamination source. These effects arise due to the movement of pesticides in surface water and can take place via drift, surface runoff and subsurface flow. A number of models have been developed to predict the behavior, mobility, and persistence of pesticides. These models should account for key hydrological processes, such as crop growth, pesticide application, transformation processes and field management practices.

In this work, Pesticide Water Calculator PWC model developed by the U.S. Environmental Protection Agency (USEPA) is applied to simulate the fate and transport of pesticides in the unsaturated zone of an aquifer. The model is used to estimate the daily concentrations of pesticides in the Valencia aquifers (Spain). In these aquifers, pesticide concentration values have been found to be greater than the Maximum Concentration Levels (MCLs) established by Spanish Legislation.

The simulations carried out in this work address different environmental scenarios and include a sensitivity analysis of the parameters used in the model. Results of the PWC model provide a crucial first step towards the development of pesticide risk assessment in Valencia region. Results also show that numerical simulation is a valid tool for the analysis and prediction of the fate and transport of pollutants in soil and groundwater.
Viscous heating triggers strain localization: Experimental evidence
Authors: Madonna Claudio , Podladchikov Yury , Burg Jean-Pierre
Published: March 2020

Strain localization is a natural deformation process that has been variously attributed to brittle, chemical or geometrical precursors. Despite some theoretical consideration, experimental evidence for temperature softening was lacking. We report thermally-activated strain localization in prismatic samples of homogenous and isotropic glassy polymer. Uniaxial compression was performed at room temperature and at different but constant displacement rates while the temperature was captured with an infrared camera. Results show temperature increase due to viscous heating along planar zones before any rupture along these zones. We validated the experimental results with a thermo-mechanical numerical model. This experimental investigation extrapolated to geological conditions shows that viscous heating can induce strain localization in all levels of deforming lithosphere.
Helmholtz Innovation Lab 3D-Underground Seismic Lab
Authors: Jaksch Katrin , Giese Rüdiger
Published: March 2020

Since 20 years the GFZ (German Research Centre for Geosciences) operates in an underground lab in the research and education mine Reiche Zeche at Freiberg in eastern Germany. This underground lab is used as testing lab for newly developed geophysical equipment and methods for 3D seismics. Therefore, in the underground space several galleries and boreholes can be used for seismic exploration in 2D and 3D approaches and for testing and validation of seismic acquisition equipment.

Now, a Helmholtz Innovation Lab will be established at the GFZ in Potsdam. The Helmholtz Innovation Lab 3D-Underground Seismic Lab (3D-US Lab) is a place where scientific expertise and the needs of industry and its customers will meet together. By involving partners from mining and tunnelling in joint development projects on a long-term basis and transferring approaches from research into commercially successful applications a sustainable 3D-US Lab will be established.

The 3D-US Lab bundles the seismic methods developed at the GFZ in a single technology platform, standardizes and modularizes them. It combines the technological and methodological developments in tunnel and borehole seismics for 3D seismic exploration of underground structures. The technology platform and the GFZ underground laboratory in Freiberg are of great interest for various partners from mining and tunnelling. In the long term the Helmholtz Innovation Lab aims to establish 3D underground seismics as a key technology for the effective and safe construction and use of underground buildings.
Recovered measurements of the 1960s stratospheric aerosol layer for new constraints for volcanic forcing in the years after 1963 Agung
Authors: Mann Graham , Antuna Marrero Juan Carlos , Maycock Amanda , McKenna Christine , Shallcross Sarah , Dhomse Sandip , Thomason Larry , Luo Beiping , Deshler Terry , Rosen James
Published: March 2020

The WCRP-SPARC initiative on stratospheric sulphur (SSiRC) has begun a new activity to recover past observational datasets of the stratospheric aerosol layer.

The data rescue activity aims to provide additional constraints for volcanic impacts on climate and is organised into three time-periods:

The quiescent period prior to the major eruption 1963 Agung eruption,

The period of strong volcanic activity during 1963-1969,

The Jul-Dec 1991 period after Pinatubo when the SAGE-II signal was saturated.

A new page within the SSiRC website gives further information on the datasets within this activity ( http://www.sparc-ssirc.org  --> Activities --> Data Rescue).

In this presentation, we explain the 1963-1969 component of the data rescue, and compare the CMIP5 and CMIP6 volcanic aerosol datasets during this period, post-Agung interactive stratospheric aerosol model simulations and a preliminary analysis of 15-year global-mean surface temperature trends from CMIP6 historical integrations for 1950-1980.

The 1960s was a strongly volcanically active decade, with the major 1963 Agung eruption and tropical stratosphere-injecting eruptions in 1965 (Taal), 1966 (Awu) and 1968 (Fernandina) generating a prolonged period of strong natural surface cooling.

Less than a year after the Agung eruption, the first in-situ measurements of a major volcanic aerosol cloud were made with dust-sondes from Minneapolis measuring aerosol particle concentrations with 10 soundings between 1963 and 1965 (6 in 1963-4).

Global surveys with the U-2 aircraft were equipped with impactors to measure stratospheric aerosol particle size distribution and composition, for example detecting the presence of volcanic ash within the Agung volcanic plume.

Early ground-based active remote sensing measurements (lidar, searchlight) also measured the vertical profile of the Agung-enhanced stratospheric aerosol layer.

The main purpose of the SSiRC data rescue is to provide constraints for interactive stratospheric aerosol models, aligning with the ISA-MIP activity, which could potentially lead to new volcanic forcing datasets for climate models, ultimately thereby aiming to improve attribution of anthropogenic change and future projections.
A review of selected parameterization schemes of WRF model over Poland area in short-term weather forecast
Authors: Kendzierski Sebastian
Published: March 2020

The aim of the work is to present simulation results of Weather Research and Forecasting (WRF) Model for high-resolution dynamical downscaling done over selected part of Poland. The research carried out a few unique simulations for selected days of the year 2019. For each model run different configuration of physical parameters (parametrization of boundary layer) were used. Additionally, two model runs were tested using the same configuration for physical parameterizations, but with two different spatial resolution. Additionally the sensitivity of the model in terms of spatial resolution was analyzed. Model was configured using two nested domains with 9 km and 3 km grid cell resolutions. All WRF simulations was simulated using GFS gribs with its initial time of 00 UTC. The results were compared with meteorological observations from meteorological stations. Results show high sensitivity of the obtained dynamical downscaling geophysical fields to the selected model configuration. High verifiability of air temperature forecasts was obtained using YSU and MYNN3 BL schemes. Mean Absolute Error (MAE) for temperature prediction has lower values in the summer season. Studies show the most optimal model configuration for BL for Poland area.
Modeling spatial snow-cover distribution using snow-melt models and MODIS images
Authors: Gyawali Dhiraj Raj , Bárdossy András
Published: March 2020

Reliable representations of spatial distribution of snow and subsequent snow-melt are critical challenges for hydrological estimations, given their crucial relevance in mountainous regimes especially because of the high sensitivity to climate change. Relatively accurate physically based models are data intensive while in-situ measurements of snow-depth are prone to be non-representative due to local influences. Likewise, lack of snow-depth information and to some extent, cloud cover in the mountains limit the usage of Remote-sensing images in snow estimation. Against this backdrop, this work presents a methodology incorporating available remotely-sensed images (MODIS Snow-cover products) and simple distributed snow-melt models to estimate a time-continuous spatial snow extent in snow dominated regimes. 

The methodology employs relatively cloud-free MODIS composite images to calibrate the spatial distribution of snow simulated by different distributed degree-day models. These variants of models are run in a domain of 500m x 500m grids, and incorporate daily precipitation, daily min-, max- and mean temperatures, and daily radiation data interpolated onto the aforementioned grids. Variations in the models include a simple degree model followed by incorporation of different aspects governing snow hydrology such as precipitation induced melt, radiation, topography, and land use.  The modeled snow depths in each grid are reclassified to ‘1’ (snow depths above a threshold) and ‘0’ (no snow), and calibrated against MODIS snow-cover for cloud-free days with snow. Snow-melt parameters are then estimated for the region of interest. The result is a spatial snow-cover distribution time-series. This approach is replicated in different regions viz. Baden-Württemberg and Bavaria in Germany, and in Switzerland. Results suggest good agreement with MODIS data and the parameters show relative stability across the time domain at the same sites and are transferrable to other regions. Calibration using readily available images used in this method offers adequate flexibility, albeit the simplicity, to calibrate snow distribution in mountainous areas across a wide geographical extent with reasonably accurate precipitation and temperature data. The final validated spatial snow-distribution data can be, as a stand-alone input, coupled with distributed hydrological models to reliably estimate streamflow in data-scarce mountainous catchments.
On the urban effects in high resolution weather forecast and regional climate simulations
Authors: Halenka Tomas , Belda Michal , Huszar Peter , Karlicky Jan , Novakova Tereza
Published: March 2020

When downscaling to higher resolution, which is common trend in operational weather forecast, air-quality prediction as well as regional climate modeling, capturing the urban effects properly becomes of primary importance to describe the impact of cities and urban structures on weather, climate and air-quality. This is necessary for proper assessment of not only impacts in the cities, but the effectiveness of adaptation and mitigation options applied within cities. It is valid not only for extreme heat waves impact prediction, but as well in air-quality prediction and in long term perspective in connection to climate change impacts. This provides the background for the project within Operational Program Prague - The Pole of Growth “Urbanization of weather forecast, air-quality and climate scenarios for Prague”, shortly URBI PRAGENSI.

In the comparison of different urban parameterizations in WRF and RegCM we demonstrate the importance of urban models in the high resolution simulations, especially under conditions of heat waves. There are differences in the impacts of such parameterizations in different models, but basically all are able to capture the effects of urban heat island in these simulations, which can be quite significant and achieve up to about 8-10 °C difference between the city and its vicinity for large cities during night time, but even in smaller cities like the City of Prague (about 1.5M), it can be more than 5°C. More detailed analysis of the effects in terms of energy balance in the city and remote areas in high resolution simulations will be presented, as well as the impacts on other parameters, especially those connected to air-quality like mixing layer height, stability, etc., where the proper choice of the parameterization really matters and simplistic option like bulk in WRF rather fails.

CORDE FPS on urbanization, which is under preparation, will be introduced with its aims and potential tasks.
Influence of depositional environments on the contamination record of fluvial sediments: a case study from the Rhône River (France)
Authors: Vauclin Sophia , Mourier Brice , Dendievel André-Marie , Noclin Nicolas , Piégay Hervé , Marchand Philippe , Winiarski Thierry
Published: March 2020

In the context of increasing anthropic pressures on river systems, including river regulations, land-use changes, and widespread contamination, sediment deposits can act as critical archives of the hydro-sedimentary processes and of the impact of such pressures on river corridors. Depositional environments and their degree of connectivity with the main channel may, however, influence the nature, chronology, and continuity of sedimentary records. This point is highlighted through a case study in a reach of the Rhône River (Péage-de-Roussillon, France) subjected to strong anthropogenic pressures (river training, by-passing hydropower production, contamination). Sediment cores were retrieved from four distinct depositional environments with different levels of connectivity with the main channel: a floodplain, a semi-active secondary channel, a fully connected secondary channel and a small impoundment. A multi-proxy characterization of the cores was conducted, including grain-size, total organic carbon content, historical and emerging contaminants (metallic elements, various organic pollutants such as polychlorinated biphenyls and brominated flames retardants, etc.), and dating techniques. The analysis of these parameters shows that each environment recorded a different time period comprised between the 19th century and nowadays and associated with distinct markers of anthropogenic activities: the less the environment is connected, the older the record is. By combining the different cores, successive contamination trends can be reconstructed over time. In particular, a shift from polychlorinated biphenyls (PCBs) to polybrominated diphenyl ethers (PBDEs) as the predominant contaminant can be observed in the 1970s-1980s; such contamination sequence has hardly ever been documented in the literature. The diversity of depositional environments also allows identifying two types of infrastructure-induced legacy sediments deriving from two distinct periods of river engineering in the area. Overall, this work illustrates the spatial variability of sediment records in fluvial environments and the importance of retrieving multiple cores in diversified depositional environments to obtain an accurate and comprehensive archive of river contamination and functioning.
Issues with fracturing ice during an ice drilling project in Greenland (EastGRIP)
Authors: Weikusat Ilka , Wallis David , Franke Steven , Stoll Nicolas , Westhoff Julien , Hansen Steffen Bo , Popp Trevor James , Wilhelms Frank , Dahl-Jensen Dorthe
Published: March 2020

Drilling an ice core through an ice sheet (typically 2000 to 3000 m thick) is a technical challenge that nonetheless generates valuable and unique information on palaeo-climate and ice dynamics. As technically the drilling cannot be done in one run, the core has to be fractured approximately every 3 m to retrieve core sections from the bore hole. This fracture process is initiated by breaking the core with core-catchers which also clamp the engaged core in the drill head while the whole drill is then pulled up with the winch motor.

 

This standard procedure is known to become difficult and requires extremely high pulling forces (Wilhelms et al. 2007), in the very deep part of the drill procedure, close to the bedrock of the ice sheet, especially when the ice material becomes warm (approximately -2°C) due to the geothermal heat released from the bedrock. Recently, during the EastGRIP (East Greenland Ice coring Project) drilling we observed a similar issue with breaking off cored sections only with extremely high pulling forces, but started from approximately 1800 m of depth, where the temperature is still very cold (approximately -20°C). This has not been observed at other ice drilling sites. As dependencies of fracture behaviour on crystal orientation and grain size are known (Schulson & Duval 2009) for ice, we thus examined the microstructure in the ice samples close to and at the core breaks.

 

First preliminary results suggest that these so far unexperienced difficulties are due to the profoundly different c-axes orientation distribution (CPO) in the EastGRIP ice core. In contrast to other deep ice cores which have been drilled on ice domes or ice divides, EastGRIP is located in an ice stream. This location means that the deformation geometry (kinematics) is completely different, resulting in a different CPO (girdle pattern instead of single maximum pattern). Evidence regarding additional grain-size dependence will hopefully help to refine the fracturing procedure, which is possible due to a rather strong grain size layering observed in natural ice formed by snow precipitation.

 

---------------------

Wilhelms, F.; Sheldon, S. G.; Hamann, I. & Kipfstuhl, S. Implications for and findings from deep ice core drillings - An example: The ultimate tensile strength of ice at high strain rates. Physics and Chemistry of Ice (The proceedings of the International Conference on the Physics and Chemistry of Ice held at Bremerhaven, Germany on 23-28 July 2006), 2007, 635-639

Schulson, E. M. & Duval, P. Creep and Fracture of Ice. Cambridge University Press, 2009, 401
Investigation of the added value of a varying coherence threshold for CryoSat-2 swath processing
Authors: Havelund Natalia , S. Sørensen Louise , B. Simonsen Sebastian
Published: March 2020

In a changing climate it is important to continuously monitor the Greenland Ice Sheet (GrIS) in relation to global sea level rise (Gardner et al., 2013). The margin of the GrIS is the most sensitive to climate changes and responds quickly.

Here, we study how to improve the sensing capabilities of the marginal areas by applying the novel swath processing technique of interferometric SAR radar data, which is only available from the SIRAL altimeter onboard the Cryosat-2 satellite. In contrast to traditional Point-of-closest-approach (POCA) processing of radar altimeter data, the swath processing delivers a band of data far from nadir and beyond the POCA point. Despite the swath processing, in comparison with POCA, delivers millions of extra data points (Foresta et al., 2018) the new estimates come with a lower signal-to-noise ratio and the method can be optimized further. Here, we investigate the added value of, under suitable surface conditions, to lower the coherence limit to derive the optimal number of observation points and still keep an acceptable signal-to-noise ratio. This will allow us to get the most out of each Cryosat-2 waveform. The validation is further aided by the inter-comparison to airborne data collected during the ESA CryoVEx campaigns.

 
Study on transport upscaling of Advection or Diffusion dominated process
Authors: Guo Zhilin , Pauloo Rich , Fogg Graham E. , Henri Christopher , Zheng Chunmiao
Published: March 2020

Regional scale transport models are needed to support the long-term evaluation of groundwater quality and to develop management strategies aiming to prevent serious groundwater degradation. The transport dominant process, advection or diffusion, was identified for flow fields with different primary flow directions. The capacities of Multi-Rate Mass Transfer (MRMT) and adaptive Multi-rate Mass Transfer (aMMT), modified from MRMT by updating mass transfer rates with changing velocities, to adequately describe the main solute transport processes, including the capture of late-time tails under changing boundary conditions were evaluated. Advective-dispersive contaminant transport simulated in a 3D heterogeneous medium was used as a reference solution. Equivalent transport under homogeneous flow conditions was then evaluated by applying the MRMT or aMMT models for upscaling. Results indicated that for advection-dominated transport, both the MRMT and aMMT methods can upscale the anomalous transport dynamics affected by sub-grid heterogeneity under transient flow conditions. Whereas, for diffusion-dominated systems, the MRMT model failed to capture the tails of tracer breakthrough curves (BTCs) after the boundary condition changed, but the results from the aMMT model were significantly improved. However, if the overall flow direction changed, both MRMT and aMMT failed to represent the BTC tail generated by the heterogeneous system. In this study, an indicator that describe the primary flow direction in anisotropic heterogeneous domain was developed, and the relationship between the flow direction and the dominant transport process was investigated. The ranges of the indicator, within which the advection or diffusion is dominant, are determined. Therefore, this study not only show the capability of upscaling methods on describing the transport that dominated by different processes, but provides a guide on choosing upscaling methods in field site, which supports long-term management of groundwater.
Analysis and forecast of wildfires using Copernicus data and services
Authors: Vitolo Claudia , Di Giuseppe Francesca , Parrington Mark
Published: March 2020

Copernicus is the European Union’s Earth Observation programme aiming at monitoring and forecasting the state of the environment on land, sea and in the atmosphere, in order to support climate change mitigation and adaptation strategies, the efficient management of emergency situations and improve the security of every citizen.

Copernicus has created a wealth of datasets related to the forecasting of wildfire danger as well as the detection of wildfire events and related emissions in the atmosphere. These products contribute to the operational services provided by the Copernicus Emergency Management Service (CEMS) and the Copernicus Atmosphere Monitoring Service (CAMS) and consists of real time forecasts as well as historical datasets based on ECMWF reanalysis database ERA5. Most of these data are available through the Copernicus Climate Data Store (CDS) and the Global Wildfire Information System (GWIS).

We will present the complete wildfire-related data offering under the Copernicus CDS and GWIS and showcase how data can be post-processed and visualised using the caliver R package.
An automatic algorithm for the detection and the characterization of cloud boundaries from BAQUNIN LIDAR signals
Authors: Iannarelli AnnaMaria , Cacciani Marco , Mevi Gabriele , Casadio Stefano , Di Bernardino Annalisa
Published: March 2020

The lidar LIDAR system is widely used in atmospheric aerosol and boundary layer (BL) studies, and for the detection of cloud boundaries. However automatic and accurate identification of cloud top and bottom heights and BL height is not trivial, especially for low signal to noise ratio values, and for cloud layers below the top of BL, because of the disentanglement of cloud and aerosol contribution to LIDAR signal.

In this work, a signal threshold approach is presented, starting from the Range Corrected Signal (RCS) and using its spatial and temporal variations. The approach has been tested using one year of acquisitions of the elastic LIDAR hosted in the BAQUNIN (Boundary-layer Air QUality analysis using Network of INstruments) Supersite(https://www.baqunin.eu) with a spatial and temporal resolution of 7.5 m and 10 s, respectively.

A minimum threshold value Tc applied to the RCS values allows detecting the presence of a cloud layer. This approach could be applied to each type of acquired LIDAR elastic signal, but depends on the specific LIDAR channel characteristics, in particular the signal to noise ratio.

RCS values obtained for each acquired profile and altitude could be considered as a two-dimensional matrix M. As first step the elements Mij>Tc of this matrix are labeled as possible cloud elements.

Subsequently, the algorithm excludes from the calculation the elements Mij corresponding to spike values or affected by high noise considering the spatial and temporal variations of the RCS. A labeled element is confirmed to be a cloud element if the number of its labeled neighbors is above a selected percentage threshold Tperc. The grid of elements considered as neighbors can be defined according to spatial and temporal resolution of the LIDAR acquisition.

Finally, bottom and top of cloud layers are retrieved as the altitude of first and last labeled elements of each cloud layer and profile.

The accuracy of the results depends on the spatial and temporal resolution of the acquired signal, considering the BAQUNIN LIDAR characteristics the best accuracy is 15 m and 20 s.

The same approach could be used to distinguish aerosol from cloud layers, using a different threshold value for the aerosol.

This method was tested for different atmospheric conditions and results are discussed in this work.
Optimal location and sizing of small hybrid systems in micro-grid system using Volunteer Geographic Information
Authors: Valdes Javier , Wöllmann Sebastian , Zink Roland
Published: March 2020

Optimal location and sizing of small hybrid systems in micro-grid system using Volunteer Geographic Information

 

This study presents an optimization model for the optimal location and sizing of small hybrid systems in simulated micro-grids. By using an optimization model - in combination with COSMO-REA2 weather data - various micro-grids local energy systems are simulated using the Calliope energy simulation model. The Calliope optimization and simulation model is feed with GIS-data from different Volunteered Geographic Information projects, including OpenStreetMap. These allows to automatically allocate specific demand profiles to diverse OpenStreetMap building categories. Moreover, based on the characteristics of the OpenStreetMap data, a set of possible distributed energy resources) including renewables and fossil fueled generators are defined for each building category. The optimization model is applied for a set of scenarios based on different electricity prices and technological characteristics. This allows to assess the impact and profitability of the different technological options on the micro-grid configuration. Moreover, in order to assess the impact of each of the scenarios on the current distribution infrastructure, the results of the simulations are included on an existing model of the low and middle voltage network for Lower Bavaria, Germany. Finally, to facilitate their dissemination, the results of the simulation are stored in a PostgreSQL database, before they are delivered by a RESTful Laravel Server and displayed in an Angular Web-Application.
Ground motion and PSI density analysis from Envisat and Sentinel1a InSAR data in the context of a complex landslide monitoring strategy in Karnali river basin, Far-Western Nepal
Authors: Schiller Arnulf , Vecchiotti Filippo , Amabile Anna Sara , Guardiani Carlotta , Dhital Megh Raj , Dhakal Amrit , Pant Bharat Raij , Ostermann Marc , Supper Robert
Published: March 2020

Continuous INSAR-monitoring of slow mass movements in the surrounding of fast (m/year) or acute processes can deliver important data complementing geomorphologic information in order to understand the broader dynamic context in which a landslide is situated. In course of the Landslide-EVO project (NERC/SHEAR funded), focusing on flood and landside risk assessment and mitigation in the Karnali river basin region in Far Western Nepal by inclusion of local community, this has been evaluated within a test of integrated monitoring methods (comprising eg. ERT, UAV-photogrammetry, D-GPS/geodesy, microseismics, soil water saturation, rainfall, and other) on regional as well as local scale at two selected sites at Bajura and Sunkoda. It was possible to derive extended information about movements in a ROI covering 120 km by 120 km. The PSI/SBAS based velocity analysis exhibits density variations due to specific slope/sensor system geometry, vegetation, data gaps, atmospheric conditions, and high velocities in the most active sites, which causes decorrelation. However, in the less active surrounding of active landslides the velocity information shows generally higher density. INSAR techniques could well complement optical image analysis in the low velocity range of centimetres to several decimetres per year, generally too slow for optical satellite image analysis in this time scale. InSAR-data has the potential to be used for estimating a slow moving masses acceleration or a deep-seated gravitational slope deformations cumulative displacement leading to a partial or total reactivation before other indication appears. It has been shown that large and difficult accessible areas can be monitored with InSAR techniques, while specific sites are equipped with corner reflectors for better signal. The study represents the first of this kind in the region and proves the ability of INSAR techniques for retrieving critical information about mass movements affecting local communities in the Karnali river basin as an example of a developing region.