bluuebunny/crossref_metadata_2025 huggingface dataset:
Global drying of major saline lakes
Authors: Jarsjö Jerker , Thorslund Josefin
Published: March 2021

Water resources are deteriorating across the world, which is of particular concern in water-scarce arid and semi-arid regions. Saline lakes often lack outflow, and are vulnerable to environmental change. When they start to shrink, salinity levels increase, due to evapoconcentration of salts in the reduced water volumes. This may harm the aquatic environment and limit the usability for humans. The associated exposure of their dry lakebeds may also bring severe regional problems of wind-blown saline dust and soil degradation. Although some of the world’s major cases of lake drying have been well studied, like the case of the Aral Sea desiccation, there is a lack of coherent assessments made at the global scale. Such assessments are critical for identifying vulnerable regions and main drivers of change, which may contribute to the prevention of future catastrophes. We here synthesise information on and analyse the desiccation status of 28 major saline lakes, each one of them having a surface area of ≥ 100 km2 and salinity of ≥ 10 g·L-1. They are geographically distributed over the world’s all continents, except Europe and Antarctica. In total, our results show that more than half of the world’s major saline lakes have dried up considerably in the last couple of decades. Out of these, 36 % are already, or are close to being completely desiccated. Preliminary analyses show correlations between original lake depth, lake bathymetry and resulting lakebed exposure from drying, suggesting that a lake’s general resilience to drying may be predictable. Our estimates further show that the world’s major saline lakes together contain 1177 billion tonnes of salt, of which 79 billion tonnes are currently in drying or already dried up lakes. If all of these lakes would desiccate, around 1 billion people are currently living within reach of saline dust storms that could spread from dry lakebeds.
Sedimentary processes on the continental slope north of Kvitøya (northern Barents Sea) – preliminary results from regional bathymetry and sediment cores
Authors: Kollsgård Christine Tømmervik , Laberg Jan Sverre , Rydningen Tom Arne , Forwick Matthias , Husum Katrine , Lasabuda Amando
Published: March 2021

The continental margin of the northern Barents Sea is a key area for understanding the behavior and dynamics of the northern Barents Sea Ice Sheet, as well as the Arctic ocean circulation pattern during the Last Glacial Maximum, the deglaciation, and the Holocene.

In this study, we investigate the continental slope north of Kvitøya and Nordaustlandet (Svalbard) by analyzing the seabed morphology of the improved IBCAO 4.0 bathymetric grid (Jakobsson et al., 2020) and high-resolution sub-bottom profiles (CHIRP), one giant piston core and three gravity cores (4.61 to 18 m long). We present results from the multi-proxy analysis of the sediment cores, including lithostratigraphy, physical properties, grain-size distribution, XRF core scanning data, and radiocarbon dates.

The morphology of the Kvitøya Trough-Mouth Fan is generally smooth, with furrows 500 m wide and 200-500 m deep stretching from the shelf edge at around 250 m water depth to at least 3000 m water depth into the Arctic Ocean. The morphology of the continental slope east and west of the trough-mouth fan is smooth in the upper parts, and characterized by 3-5 km wide and 200-500 m deep channels and canyons cutting into the slope from a water depth of around 1000 to 3000 m.

The observations from the bathymetric data show that the trough-mouth fan buries channels and canyons, smoothing the morphology of the continental slope. The furrows are likely erosional features resulting from downslope activity such as debris flows and turbidity currents. In the inter-fan areas to the east and west, we interpret that the uppermost smooth morphology results from suspension fallout of sediments from the ocean currents flowing along-slope, indicating that these accumulations are contourites. The rugged topography further downslope possibly represents channel and canyon systems that are only partially buried, likely due to reduced influence from ocean currents at greater water depths. Analysis of the cores provides insight on the sediment properties of the contourites, debris flows, and turbidites, and radiocarbon dates shed light on the interplay and timing of the ocean current regime and the glacial dynamics.

 

Jakobsson, M., Mayer, L.A., Bringensparr, C. et al. The International Bathymetric Chart of the Arctic Ocean Version 4.0. Sci Data 7, 176 (2020). https://doi.org/10.1038/s41597-020-0520-9
Preliminary field data of selected deep-rooted vegetation effects on the slope-vegetation-atmosphere interaction: results from an in-situ test 
Authors: Tagarelli Vito , Cotecchia Federica , Bottiglieri Osvaldo
Published: March 2021

The soil-vegetation-atmosphere interaction is becoming more and more the subject of intense scientific research, motivated by the wish of using smart vegetation implants as sustainable mitigation measure for erosive phenomena and slope instability processes. 
The use of novel naturalistic interventions making use of vegetation has been already proven to be successful in the reduction of erosion along sloping grounds, or in increasing the stability of the shallow covers of slopes, whereas the success of vegetation as slope stabilization measure still needs to be scientifically proven for slopes location of deep landslides, whose current activity is climate-induced, as frequent in the south-eastern Apennines. Recently, though, peculiar natural perennial grass species, which develop deep root systems, have been found to grow in the semi-arid climate characterizing the south-eastern Apennines and to determine a strong transpirative flow. Therefore, their peculiar leaf architecture, their crop density, combined with their perennial status and transpiration capacity, make such grass species suitable for the reduction of the net infiltration rates, equal to the difference between the rainfall rate and the sum of the runoff plus the evapotranspiration rate. As such, the grass species here of reference have been selected as vegetation measure intended to determine a reduction of the piezometric levels in the slope down to large depths, in order to increase the stability of deep landslide bodies. 
At this stage, only preliminary field data representing the interaction of clayey soils with the above cited vegetation species are available. These have been logged within a full scale in-situ test site, where the deep-rooted crop spices have been seeded and farmed. The test site (approximatively 2000 m2) has been set up in the toe area of the climate-induced Pisciolo landslide, in the eastern sector of the Southern Apennines.
The impact of the vegetation on the hydro-mechanical state of the soil is examined in terms of the spatial and temporal variation of the soil water content, suction an pore water pressure from ground level down to depth, both within the vegetated test site and outside it, where only spare wild vegetation occur, in order to assess the effects of the implant of the selected vegetation. The soil water contents, suctions and pore water pressures have been also analyzed taking into account of the climatic actions, monitored by means of a meteorological station. 
From morpho-stratigraphic to geo-stratigraphic units: the PLANMAP contribution.
Authors: Massironi Matteo , Rossi Angelo Pio , Wright Jack , Zambon Francesca , Poehler Claudia , Giacomini Lorenza , Carli Cristian , Ferrari Sabrina , Semenzato Andrea , Luzzi Erica , Pozzobon Riccardo , Tognon Gloria , Rothery David A. , Van der Bogert Carolyn , Altieri Francesca
Published: March 2021

Geological units on Earth are defined by several parameters besides the stratigraphic ones, such as rock textures, lithology, composition, and environmental conditions of their origin (numerous and diverse magmatic, volcanic, metamorphic and sedimentary environments). On the other hand, from the Apollo era onward, planetary ‘geologic’ mapping has been carried out using a photo-interpretative approach mainly on panchromatic and monochromatic images. This limited the definition of geological units to morpho-stratigraphic considerations so that units were mainly defined by their stratigraphic position, surface textures and morphology, and attribution to general emplacement processes (a few related to magmatism, some broad sedimentary environments, some diverse impact domains, and all with uncertainties of interpretation). Hence, the two products are still separated by an important conceptual and effective gap which makes the traditional planetary morpho-stratigraphic maps unable to satisfy fully the needs of modern planetary exploration, i.e. an optimised product to define mission strategy in terms of target selection, exploration traverse definition and resource evaluation for ISRU purposes. One of the approaches that might close this gap is to integrate spectral, color and compositional information into morpho-stratigraphic maps, thus generating spectro-morphic or geo-stratigraphic maps.

The PLANMAP team has explored diverse methods for the integration of color variation and spectral information into planetary geological maps that diverge on the bases of the data available, the planetary surface under consideration (Moon, Mars and Mercury),the  geological environments and the scale of mapping.

 

PLANMAP received funding from the European Union Horizon 2020 research and innovation program under grant agreement N. 776276.
Jointly learning variational data assimilation models and solvers for geophysical dynamics
Authors: Fablet Ronan , Chapron Bertrand , Drumetz Lucas , Memin Etienne , Pannekoucke Olivier , Rousseau François
Published: March 2021

This paper addresses representation learning for the resolution of inverse problems  with geophysical dynamics. Among others, examples of inverse problems of interest include space-time interpolation, short-term forecasting, conditional simulation w.r.t. available observations, downscaling problems… From a methodological point of view, we rely on a variational data assimilation framework. Data assimilation (DA) aims to reconstruct the time evolution of some state given a series of  observations, possibly noisy and irregularly-sampled. Here, we investigate DA from a machine learning point of view backed by an underlying variational representation.  Using automatic differentiation tools embedded in deep learning frameworks, we introduce end-to-end neural network architectures for variational data assimilation. It comprises two key components: a variational model and a gradient-based solver both implemented as neural networks. A key feature of the proposed end-to-end learning architecture is that we may train the neural networks models using both supervised and unsupervised strategies. We first illustrate applications to the reconstruction of Lorenz-63 and Lorenz-96 systems from partial and noisy observations. Whereas the gain issued from the supervised learning setting emphasizes the relevance of groundtruthed observation dataset for real-world case-studies, these results also suggest new means to design data assimilation models from data. Especially, they suggest that learning task-oriented representations of the underlying dynamics may be beneficial. We further discuss applications to short-term forecasting and sampling design along with preliminary results for the reconstruction of sea surface currents from satellite altimetry data. 

This abstract is supported by a preprint available online: https://arxiv.org/abs/2007.12941
Surface gravimetry on Dimorphos  
Authors: Karatekin Özgür , Ritter Birgit , Carrasco Jose , Noeker Matthias , Umit Ertan , Vanransbeeck Emiel , Alaves Higinio , Tasev Elisa , Goli Marta , Van waal Stefaan , Goldberg Hannah
Published: March 2021

In the frame work of HERA mission, the gravimeter for small solar system objects (GRASS) has been developed to measure the local acceleration vector on the surface of the moonlet of the binary asteroid, Dimorphos. GRASS will be onboard Juventas CubeSat which is one of the two daughtercraft of ESA’s Hera spacecraft. Launched in 2024 it will arrive in the binary system in 2026. Following the soft-landing of the Juventas CubeSat, GRASS will record the temporal variation of the surface gravity vector.

The average gravitational force expected on the Dimorphos surface is around 5 x 10-5 m s-2 (or 5 mGal). Apart from the self-gravitation of the body, centrifugal forces and the acceleration due to the main body of the system contribute to the surface acceleration. The temporal variations of local gravity vector at the landing site will be used to constrain the geological substructure (mass anomalies, local depth and lateral variations of regolith) as well as the surface geophysical environment (tides, dynamic sloped and centrifugal forces).

We will present the GRASS science objectives in the Hera mission the operational concept that is foreseen to reach these objectives, its current status of development including first test results and the by simulation estimated performances of the instrument.

 
Large-scale, high-resolution maps of interseismic strain accumulation from Sentinel-1, and incorporation of along-track measurements
Authors: Hooper Andy , Piromthong Pawan , Wright Tim , Weiss Jonathan , Milan Lazecky Milan , Maghsoudi Yasser , Rollins Chris , Morishita Yu , Elliott John , Parsons Barry
Published: March 2021

High-resolution geodetic measurements of crustal deformation from InSAR have the potential to provide crucial constraints on a region’s tectonics, geodynamics and seismic hazard. Here, we present a high-resolution crustal velocity field for the Alpine-Himalayan Seismic Belt (AHSB) derived from Sentinel-1 InSAR and GNSS. We create time series and average velocities from ~220,000 interferograms covering an area of 15 million km2, with an average of 170 acquisitions per measurement point. We tie the velocities to a Eurasian reference frame by jointly inverting the InSAR data with GNSS data to produce a low-resolution model of 3D surface velocities. We then use the referenced InSAR velocities to invert for high-resolution east-west and sub-vertical velocity fields for the entire region. The sub-vertical velocities, which also include a small component of north-south motion, are dominated by non-tectonic deformation, such as subsidence due to water extraction. The east-west velocity field, however, reveals the tectonics of the AHSB with an unprecedented level of detail.

The approach described above only provides good constraints on horizontal displacement in the east-west direction, with the north-south component provided by low-resolution GNSS measurements. Sentinel-1 does also have the potential to provide measurements that are sensitive to north-south motion, through exploitation of the burst overlap areas produced by the TOPS acquisition mode. These along-track measurements have lower precision than line-of-sight InSAR and are more effected by ionospheric noise, but have the advantage of being almost insensitive to tropospheric noise. We present a time series approach to tease out the subtle along-track signals associated with interseismic strain. Our approach includes improvements to the mitigation of ionospheric noise and we also investigate different filtering approaches to optimize the reduction of decorrelation noise. In contrast to the relative measurements of line-of-sight InSAR, these along-track measurements are automatically provided in a global reference frame. We present results from five years of data for the West-Lut Fault in eastern Iran and the Chaman Fault in Pakistan and Afghanistan. Our results agree well with independent GNSS measurements; however, the denser coverage of the technique allows us to also detect the variation in slip rate along the faults.

Finally, we demonstrate the improvement in the resolution of horizontal strain rates when including these along-track measurements, in addition to the conventional line-of-sight InSAR measurements.
Updated attribution of GSAT changes and implications
Authors: Ribes Aurélien , Qasmi Saïd , Gillett Nathan
Published: March 2021

The observed increase of global air surface temperature (GSAT) has long been attributed to human activities. However, updating estimates of human-induced changes, and changes induced by specific subsets of forcings (e.g., green-house gases) remains of high interest to better understand recent changes and also produce refined projections.

Here, we use the newest climate model ensemble (CMIP6), improved observations, and a new statistical method to narrow uncertainty on the response to historical forcings. In addition, we focus on estimating the total warming since the pre-industrial (using 1850-1900 as a reference baseline), while most previous studies considered shorter periods.

Results suggest that most of the observed warming since the pre-industrial (+1.22°C +/-0.15°C in 2020) is human-induced (+1.15°C +/-0.15°C) and that a substantial fraction of GHG-induced warming (+1.54°C +/-0.33°C) has been offset by other anthropogenic factors (-0.39°C +/-0.28°C). We also quantify the contribution of specific forcings to the 2010-2019 warming rate, suggesting that the current rate of human-induced warming is +0.22°C/decade (+/-0.05°C/decade). We then derive implications of these findings in terms of future climate change, i.e., the response to a range of scenarios. Our results suggest that historical observations and historical climate change are already very informative about future changes and the property of the Earth System in general.
Whole System Approach for in-situ research on Life Supporting Systems in the Anthropocene (WAILS)
Authors: Mirtl Michael , Kuhn Ingolf , Montheith Don , Bäck Jaana , Orenstein Daniel , Provenzale Antonello , Zacharias Steffen , Haase Peter , Shachak Mosche
Published: March 2021

Driven by the increasing awareness that innovative approaches to solving the problems at hand in our complex human-environment interactions require closer collaboration among scientific disciplines and communities, inter- and transdisciplinary integration is continuously gaining importance in R&D agendas and Research Infrastructure (RI) development strategies. In addition, the complexity and costs of RIs have substantively increased in many realms triggered by technological developments and the need to organize beyond national and continental boundaries. This suggests cross-disciplinary collaborations, sharing and multiple usage of infrastructures. Alignments of infrastructure developments needed for this purpose require a conceptual framework for disciplinary integration suited for identifying common approaches and resulting infrastructure design and service components. We will report on recent advancements in building a common theoretical base between major communities that is – inter alia - underlying the ongoing implementation of the Integrated European Ecosystem, critical zone and socio-ecological Research Infrastructure (eLTER RI). An overview of considered theories  on within- and cross-scale interactions and feedback loops will be given and the pathway to the “Whole System Approach for in-situ research on Life Supporting Systems in the Anthropocene” (WAILS) will be presented. We will also expand on the potential of such unifying approach in theory-guided integration and division of tasks amongst related environmental RIs. Expected practical implications are answers to questions like where concretely existing and planned European environmental RIs are challenged to interact in response to common overarching questions, and what practical fora and mechanisms (across RIs) would be needed to bridge the gap between research teams driven (bottom-up) efforts and the centralistic RI design and operations.
Real-time and near real-time ZTD from a local network of low-cost dual-frequency GNSS receivers.
Authors: Hadas Tomasz , Marut Grzegorz , Kapłon Jan , Rohm Witold
Published: March 2021

The dynamics of water vapor distribution in the troposphere, measured with Global Navigation Satellite Systems (GNSS), is a subject of weather research and climate studies. With GNSS, remote sensing of the troposphere in Europe is performed continuously and operationally under the E-GVAP (http://egvap.dmi.dk/) program with more than 2000 permanent stations. These data are one of the assimilation system component of mesoscale weather prediction models (10 km scale) for many nations across Europe. However, advancing precise local forecasts for severe weather requires high resolution models and observing system.   Further densification of the tracking network, e.g. in urban or mountain areas, will be costly when considering geodetic-grade equipment. However, the rapid development of GNSS-based applications results in a dynamic release of mass-market GNSS receivers. It has been demonstrated that post-processing of GPS-data from a dual-frequency low-cost receiver allows retrieving ZTD with high accuracy. Although low-cost receivers are a promising solution to the problem of densifying GNSS networks for water vapor monitoring, there are still some technological limitations and they require further development and calibration.

We have developed a low-cost GNSS station, dedicated to real-time GNSS meteorology, which provides GPS, GLONASS and Galileo dual-frequency observations either in RINEX v3.04 format or via RTCM v3.3 stream, with either Ethernet or GSM data transmission. The first two units are deployed in a close vicinity of permanent station WROC, which belongs to the International GNSS Service (IGS) network. Therefore, we compare results from real-time and near real-time processing of GNSS observations from a low-cost unit with IGS Final products. We also investigate the impact of replacing a standard patch antenna with an inexpensive survey-grade antenna. Finally, we deploy a local network of low-cost receivers in and around the city of Wroclaw, Poland, in order to analyze the dynamics of troposphere delay at a very high spatial resolution.

As a measure of accuracy, we use the standard deviation of ZTD differences between estimated ZTD and IGS Final product. For the near real-time mode, that accuracy is 5 mm and 6 mm, for single- (L1) and dual-frequency (L1/L5,E5b) solution, respectively. Lower accuracy of the dual-frequency relative solution we justify by the missing antenna phase center correction model for L5 and E5b frequencies. With the real-time Precise Point Positioning technique, we estimate ZTD with the accuracy of 7.5 – 8.6 mm. After antenna replacement, the accuracy is improved almost by a factor of 2 (to 4.1 mm), which is close to the 3.1 mm accuracy which we obtain in real-time using data from the WROC station.
The Saharides: Turkic-Type Orogeny in Afro-Arabia
Authors: Şengör A. M. Celal , Lom Nalan , Zabcı Cengiz , Sunal Gürsel , Öner Tayfun
Published: March 2021

We describe a major new Neoproterozoic orogenic system belonging to the larger Pan-African deformational realm, the Saharides, in North Africa, by using various tools such as magnetic maps and our own remote-sensing based structural interpretation to aid us in following the orogenic trend-lines in addition to a large compilation of geochronological data. The Saharides, a Turkic-type orogenic complex similar to the Altaids of central and northwestern Asia, involved major subduction accretion complexes occupying almost the entire Arabian Shield and much of Egypt and Sudan and the small inliers of such complexes farther west to and including the Ahaggar mountains. These complexes are formed at least by half from juvenile material representing at least 5 million km2 new continental crust formed during the Neoproterozoic from about 900 to 500 Ma ago. Contrary to conventional wisdom in the areas they occupy, the Saharides involved no continental collisions until the very end of their history, but evolved by subduction and strike-slip stacking of arc material mainly by pre-collisional coast-wise transport of arc fragments shaved off the Congo/Tanzania cratonic nucleus in a manner very similar to the development of the Nipponides in east Asia, parts of the North American Cordillera and the Altaids. The entire Sahara is shown to be underlain by a double orocline much like the Hercynian double orocline in western Europe and northwestern Africa and not by an hypothetical ‘Saharan Metacraton’. The method here followed may be a fruitful procedure to untangle the structure of some of the Precambrian orogenic belts before life evolved sufficiently to make biostratigraphy feasible.
Effects of climate change and human interactions on water balance dynamics in the River Vistula basin
Authors: Romanowicz Renata , Karamuz Emilia , Napiorkowski Jaroslaw , Senbeta Tesfaye
Published: March 2021

Water balance modelling is often applied in studies of climate and human impacts on water resources. Annual water balance is usually derived based on precipitation, discharge and temperature observations under an assumption of negligible changes in annual water storage in a catchment. However, that assumption might be violated during very dry or very wet years. In this study we apply groundwater level measurements to improve water balance modelling in nine sub-catchments of the River Vistula basin starting from the river sources downstream. Annual and inter-annual water balance is studied using a Budyko framework to assess actual evapotranspiration and total water supply. We apply the concept of effective precipitation to account for possible losses due to water interception by vegetation. Generalised Likelihood Uncertainty Estimation GLUE is used to account for parameter and structural model uncertainty, together with the application of eight Budyko-type equations. Seasonal water balance models show large errors for winter seasons while summer and annual water balance models follow the Budyko framework. The dryness index is much smaller in winter than in summer for all sub-catchments. The spatial variability of water balance modelling errors indicate an increasing uncertainty of model predictions with an increase in catchment size. The results show that the added information on storage changes in the catchments provided by groundwater level observations largely improves model accuracy. The results also indicate the need to model groundwater level variability depending on external factors such as precipitation and evapotranspiration and human interventions. The modelling tools developed will be used to assess future water balance in the River Vistula basin under different water management scenarios and climate variability.
Venus, an Astrobiology Target
Authors: Limaye Sanjay , Mogul Rakesh , Baines Kevin , Bullock Mark , Cockell Charles , Cutts James , Gentry Diana , Head James , Jessup Kandis-Lea , Kompanichenko Vladimir , Lee Yeon Joo , Mathies Richard , Milojevic Tetyana , Pertzborn Rosalyn , Rothschild Lynn , Schulze-Makuch Dirk , Smith David , Way Michael
Published: March 2021

The interest in the possibility of life on Venus is driven not just by curiosity about life originating in another Earth-like environment, but because of the possibility that life may be playing a critical role in the planet’s present, and possibly its past, atmospheric state. The brilliance of Venus in the night sky (as viewed from Earth) is due to its highly reflective cloud cover, about 28 km thick at the equator.  Its spectral albedo is about 90% at wavelengths > 500 nm, but it drops gradually to about 40% around 370 nm before rising slightly at shorter wavelengths.  This albedo drop is due to the presence of several absorbers in the atmosphere and the cloud cover.  A very large fraction of the energy absorbed by Venus is at ultraviolet wavelengths with sulfur dioxide above the clouds contributing to the absorption below 330 nm; however, the identities of the other absorbers remain unknown.  The inability to identify the absorbers that are responsible for determining the radiative energy balance of Venus over the last century is a major impediment to understanding how the planet “works”, a major component of NASA’s efforts in planetary exploration.  Limaye et al. (Astrobiology 18, 1181-1198, 2018) presented a hypothesis suggesting that cloud-based microbial life could be contributors to the spectral signatures of Venus’ clouds, building upon previous suggestions of the possibility of life in the clouds of Venus.

Four interconnected themes for the exploration of Venus as an astrobiology target are: – (i) investigations focused on the likelihood that liquid water existed on the surface in the past leading to the potential for the origin and evolution of life, (ii) investigations into the potential for habitable zones within Venus’ clouds and Venus-like atmospheres, (iii) theoretical investigations into how active aerobiology may impact the radiative energy balance of Venus’ clouds and Venus-like atmospheres, and (iv) application of these investigative themes towards better understanding the atmospheric dynamics and habitability of exoplanets. These themes can serve as a basis for proposed Venus Astrobiology Objectives and suggestions for measurements for future missions, as per the goals and objectives developed by the Venus Exploration Analysis Group (VEXAG), which is sponsored by NASA to plan for the future exploration of Venus.  

A Venus Collection to be published in Astrobiology journal in 2021 will include papers from the  “Habitability of the Venus Cloud Layer”, Moscow (October 2019) workshop. 
Evolution of the Black Sea Physical Analysis and Forecasting System within CMEMS
Authors: Ciliberti Stefania Angela , Jansen Eric , Azevedo Diana , Gunduz Murat , Ilicak Mehmet , Pinardi Nadia , Coppini Giovanni , Masina Simona , Lecci Rita , Causio Salvatore , Stefanizzi Laura , Creti' Sergio , Lima Leonardo , Aydogdu Ali , Peneva Elisaveta , Matreata Marius
Published: March 2021

The Black Sea physical analysis and Forecasting System (BSFS) is part of the Black Sea Monitoring and Forecasting Centre (BS-MFC) for the Copernicus Marine Service (CMEMS). It provides analysis every day analysis and 10 days forecast fields for the blue ocean variables (including temperature, salinity, sea surface height, mixed layer depth and currents) in the Black Sea region since. In this work, we present the new version of the operational system that will be part of the next CMEMS  release. The hydrodynamical core model is based on NEMO v4.0, solved on 1/40º horizontal resolution spatial grid (including the overall Black Sea, the Bosporus Strait and part of the Marmara Sea) and 121 vertical levels with z-star. The core model uses ECMWF analysis and forecast atmospheric forcing and GPCP monthly climatological precipitation for computing heat, water and momentum fluxes. A total number of 72 rivers is accounted, as monthly climatology provided by SESAME project. The model implements a new representation of the Danube River with interannual river discharge datasets provided by the National Institute of Hydrology and Water Management. One of the main innovations of this system is the opening of the Bosporus Strait by using a box-approach in a portion of the Marmara Sea: it is achieved thanks to high resolution temperature, salinity, sea surface height, zonal and meridional velocity solutions provided by a novel implementation of the Marmara Sea model including straits based on Shyfem: it represents the optimal interface between the Mediterranean and the Black Sea. The hydrodynamical model is online coupled to an upgraded version of the OceanVar, the CMCC data assimilation scheme, able to assimilate SLA L3 satellite data, T/S in-situ profiles and SST from CMEMS TACs. The contribution focuses on model setup description, processing system and validation. To evaluate BSFS pre-operational run and monitor the operational production, we provide metrics as proposed within GODAE/Oceanpredict and MERSEA/MyOcean (which includes CLASS 1, 2 and 4 metrics).
Calibration of solar radiation ensemble forecasts using convolutional neural network
Authors: Dupuy Florian , Lu Yen-Sen , Good Garrett , Zamo Michaël
Published: March 2021

Ensemble forecast approaches have become state-of-the-art for the quantification of weather forecast uncertainty. However, ensemble forecasts from numerical weather prediction models (NWPs) still tend to be biased and underdispersed, hence justifying the use of statistical post-processing techniques to improve forecast skill.

In this study, ensemble forecasts are post-processed using a convolutional neural network (CNN). CNNs are the most popular machine learning tool to deal with images. In our case, CNNs allow to integrate information from spatial patterns contained in NWP outputs.

We focus on solar radiation forecasts for 48 hours ahead over Europe from the 35-members ARPEGE (Météo-France global NWP) and a 512-members WRF (Weather Research and Forecasting) ensembles. We used a U-Net (a special kind of CNN) designed to produce a probabilistic forecast (quantiles) using as ground truth the CAMS (Copernicus Atmosphere Monitoring System) radiation service dataset with a spatial resolution of 0.2°.
Detailed analysis of extreme heatwaves in Serbia, South-East Europe
Authors: Basarin Biljana , Lukić Tin , Micić Ponjiger Tanja
Published: March 2021

A detailed analysis of extreme heatwave events in Serbia from the biometeorological point of view is presented in this study.  For this purpose, the newly developed Heat Wave Magnitude Index daily (HWMId), was used on Physiologically equivalent temperature (PET) for Serbia. A series of daily maximum air temperature, relative humidity, the wind was used to calculate PET for the investigated period 1979–2019. HWMId is defined as the maximum magnitude of the heatwaves in a year. Here, the heatwave is characterized as 3 consecutive days with maximum PET above the daily threshold for the reference period 1981–2010. The analysis revealed that during the investigated period the most intensive heat waves occurred in 2007, 2012 and 2015. HWMId values for 2007 were in the range of 8 to 23 indicating extreme heat stress, while for the other two events the values were not as high. Hourly temperatures revealed that the PET values during the day were as high as 55°C. Thus, the mitigation and adaptation to extreme temperature events are of vital importance for humans and their everyday activities. Future investigation should be oriented towards a way to deal with the oppressive heat. Additionally, more research is needed in order to explain and predict these catastrophic events. The main focus of future activities will be on determining the physical causes which lead to the occurrence of extreme heatwaves.

Keywords: Heat Wave Magnitude Index daily, Physiologically equivalent temperature, Serbia, heat waves

Acknowledgment: This research is supported by EXtremeClimTwin project funded from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 952384
Impact of climate change on runoff timing over the Hindukush Karakorum Himalaya (HKH) region using CORDEX-CORE scenario simulations
Authors: Shafeeq Wajeeha , Coppola Erika , Di Sante Fabio
Published: March 2021

Hindukush Karakorum and Himalayan (HKH) is a unique region with a vast number of glaciers and lies in the north of the South Asia landmass, which serves as the main reservoir for the South Asian freshwater resources. By using CORDEX-CORE downscaled simulations with ICTP Regional Climate Model (RegCM4.7) the climate change impact on the water resources of the HKH region is analysed. HKH contains Indus, Ganges and Brahmaputra water basins, which are feed from both snow as well as precipitation. Due to the temperature increase over this region, the snowmelt timing will be affected, and therefore the snowmelt driven runoff (SDR) in the whole HKH basin. This effect will be combined with the projected increase of precipitation and in particular convective precipitation mostly due to extreme precipitation increase. As a result for the whole HKH basin, the water year will be longer with a shift (negative) toward the earlier months of the year of the time when the 25th (~2-3 months), 50th( ~1month), and 75th (~1 month) percentile of the total runoff is observed in a certain point, in the upper part of the basin and a positive shift (~10 days) in the lower part of the basin for the 50th and 75th percentile. The results show that the Indus basin is the one most affected by the snow melt time change followed by the Brahmaputra and Ganges as the last one. This study indicates that changing climate may result in a shift in the discharge timing over the HKH region and this information may be crucial for planning the mitigation and adaptation actions like for example building dams, changing dam regulation options, and changing agriculture strategies.
Report of the D-A-CH geoid and height unification project and prospects for the extension to the European Alps and beyond
Authors: Schwabe Joachim , Ullrich Christian , Marti Urs , Liebsch Gunter , Hellerschmied Andreas , Mayer-Guerr Torsten
Published: March 2021

The D-A-CH geoid project was initiated in 2017 between the national mapping agencies of Germany (BKG), Austria (BEV) and Switzerland (swisstopo), as well as the regional authorities of the German federal states of Bavaria (LDBV) and Baden-Württemberg (LGL), with the motivation to better harmonize the basis for height determination.

In these countries, the official national height reference systems that are still in use apply different definitions of the height and the zero levels refer to different tide gauges and epochs. Additionally, the treatment of the permanent tide is not fully consistent. This causes differences at the decimeter scale which also vary along the national borders. At the same time, Austria and Switzerland do compute and store also EVRS-compatible geopotential numbers that are valuable for height system unification.

The ambitions of the initiative therefore mirror the situation as described above ‒ to foster and to intensify the cooperation between the partners regarding regional gravity field modeling and to provide better information about the transformations between the national height systems.

It was agreed that the cooperation should first focus on a case study area around Lake Constance, with envisaged extension to the complete territories of the “D-A-CH countries” and/or, ideally, to the most of the European Alps. The following achievements have been reached for the focus area:

In view of these developments, and taking into account that these challenges are not unique for this specific area, it is planned to extend this initiative to the computation of the entire European Alps (and surrounding lowland areas) and rename the project to “European Alps Geoid (EAlpG)”.

We believe that this project can contribute to a better understanding of height differences across borders. Such height differences are for instance of great interest for ground water level investigations or flood protection. Other crucial applications for cross-border height unification are engineering projects such as tunnels, bridges, supply lines, etc.

What is more, these activities shall be embedded in a pan-European geoid initiative within EUREF. Contributing to the upcoming EUREF Working Group “European Height Reference Surface”, the European Alps Geoid will be one of many cornerstones to build an official EVRS height reference surface.

Potential cooperation partners have been contacted. Nevertheless, the initiative shall be open to interested parties. A virtual meeting is planned to be held shortly after the vEGU2021.
Development of a Solar Park Carbon Calculator (SPCC) to assist deployment decisions
Authors: Holland Ryan , Armstrong Alona , Carvalho Fabio
Published: March 2021

Following the Paris agreement, many nations have committed to targets of net zero emissions, resulting in a significant increase in low-carbon energy generation. Recent improvements in the cost and efficiency of photovoltaic (PV) technology have made their deployment cheaper than new coal and gas fired power stations in a number of regions, with the uptake of PV projected to surpass fossil fuels by 2035. Large-scale, ground-mounted systems are likely to constitute a considerable portion of this expansion, with the International Energy Agency suggesting that 69% of new capacity additions in 2021 will be utility scale deployments (although some of this may be building-mounted). Despite the expansion of ground-mounted solar parks and the knowledge that land use change is a greater threat to nature than climate change, there is very little understanding of the environmental implications. In particular, the effect on ecosystem carbon cycling, and thus the decarbonisation attraction of the technology, is unknown. Whilst the carbon impacts of the technological components have been relatively well resolved, the true carbon costs cannot be determined without quantifying the impacts on land carbon. Here, we present a solar park carbon calculator (SPCC) that quantifies the full suite of solar park carbon impacts.

The SPCC provides information on the technological and environmental carbon flows, drawing on established quantifications of carbon costs for system components, operation, and land management. Key components include the emissions factors for production of panels and mounts, machinery related emissions and the associated carbon flows of ground disturbances, before and after park construction. The SPCC is applied to a case-study solar park, providing insight into the dominant carbon flows and payback time in light of grid electricity carbon intensities. Ultimately, the SPCC can help inform solar park developer decisions in order to minimise carbon costs and maximise carbon sequestration.
Characterizing temporary stream dynamics: the Stream Length Duration Curve
Authors: Durighetto Nicola , Senatore Anfonso , Botter Gianluca
Published: March 2021

Temporary streams (i.e. streams that temporarily cease to flow) are becoming a hot research topic in hydrology. These streams provide an invaluable contribution to riverine ecosystems, as they host a variety of habitats (from lotic to lentic and terrestrial) which sustain high biodiversity. Temporary streams can be found in different regions of the world and are characterized by strongly heterogeneous flow patterns, from flashy streams that flow only after rainfall events to rivers that episodically experience droughts. Many recent studies investigated temporary streams, originating interesting observational datasets about event-based or seasonal network dynamics. Empirical or conceptual models are usually employed for assessing the main physical drivers of network dynamics in each specific study site.
In this contribution, we develop and apply novel theoretical tools to understand how the local statistical properties of each reach of the network affect the catchment-scale variability of the active length. In particular, the Stream Length Duration Curve (SLDC) is proposed to efficiently summarize catchment-scale dynamics of the active length, providing an objective way to quantify network dynamics. The concept of SLDC is applied to a number of Italian headwater catchments, where data about temporal changes in the configuration of the flowing stream are available, providing a clue for the characterization of emergent temporal and spatial patterns of network dynamics. The Stream Length Duration Curve can facilitate comparisons across different catchments an time periods, possibly enabling and objective classification of temporary streams. 
Reduced ecosystem services of desert plants from ground-mounted solar energy development
Authors: Grodsky Steven M. , Hernandez Rebecca R.
Published: March 2021

Deserts are prioritized as recipient environments for solar energy development; however, the impacts of this development on desert plant communities are unknown. Desert plants represent long-standing ecological, economic and cultural resources for humans, especially indigenous peoples, but their role in supplying ecosystem services (ESs) remains understudied. We measured the effect of solar energy development decisions on desert plants at one of the world’s largest concentrating solar power plants (Ivanpah, California; capacity of 392 MW). We documented the negative effects of solar energy development on the desert scrub plant community. Perennial plant cover and structure are lower in bladed treatments than mowed treatments, which are, in turn, lower than the perennial plant cover and structure recorded in undeveloped controls. We determined that cacti species and Mojave yucca (Yucca schidigera) are particularly vulnerable to solar development (that is, blading, mowing), whereas Schismus spp.—invasive annual grasses—are facilitated by blading. The desert scrub community confers 188 instances of ESs, including cultural services to 18 Native American ethnic groups. Cultural, provisioning and regulating ESs of desert plants are lower in bladed and mowed treatments than in undeveloped controls. Our study demonstrates the potential for solar energy development in deserts to reduce biodiversity and socioecological resources, as well as the role that ESs play in informing energy transitions that are sustainable and just.
Seismic ionospheric disturbances related to Chile-Illapel 2015 earthquake and tsunami observed by Swarm and ground GNSS stations
Authors: Jarmolowski Wojciech , Wielgosz Pawel , Krypiak-Gregorczyk Anna , Milanowska Beata , Haagmans Roger
Published: March 2021

The study investigates Swarm data including in-situ electron density (ED) measured by Langmuir Probes (LP) and total electron content (TEC) from precise orbit determination (POD) GNSS receivers in time of Chile-Illapel earthquake (EQ) and tsunami in 2015. The research is based on the symbiosis of Swarm data, ground GNSS data and seismic records combined with the information on EQs and tsunamis. The FFT-based filtering and short-term Fourier transform (STFT) analysis are used in detection of seismic ionospheric disturbances (SID) in ED from LP and POD TEC data. The classification of the spectral characteristics of disturbing along-track signals is supported by their simultaneous search in ground GNSS observations, which gives an opportunity for the validation of the spectral recognition. Ground GNSS data, due to several tens of satellites and thousands of stations, provide the only full spatiotemporal view on SIDs and enable the inspection of their spatial shapes, spatial relations and speeds. The location of dense ground GNSS networks is however limited to selected places. Swarm and other LEO satellite data, in turn, are globally distributed, but they are dense only along the orbital tracks. Therefore, 1D nature of Swarm along-track observations, fast satellite movement and limited chance for spatiotemporal correlation due to the non-repeating orbits, strongly require spectral analysis for better recognition of the signals. The detection of SIDs from along-track Swarm data is also complicated due to the variety of disturbing signals occurring in the ionosphere, and the spectral analysis is also crucial there. STFT spectral approach to along-track Swarm data gives an opportunity for distinguishing the signals of different origin. The analyses of Swarm data provide interesting observations of ionospheric disturbances not only directly related with the largest EQ events and tsunami, but also occurring during entire periods of enhanced seismic activity and at larger distances from EQ epicenter. The disturbing signals triggered by the largest EQs and tsunami were also observed. However their amplitude in the ionosphere is not always such dominating as the amplitude of some other, associated disturbances on the neighboring days. This difference in scale can suggest that the electron disturbances in the ionosphere are rather more generally related to the crustal motion and seismic activity, than solely correlated with large EQs.