bluuebunny/crossref_metadata_2025 huggingface dataset:
Silver nanoparticles used to counter Monilinia fructicola fungicide-resistance and reduce fungicide environmental footprint 
Authors: Chrysikopoulos Constantinos , Malandrakis Anastasios A. , Kavroulakis Nektarios , Stefanarou Anthi
Published: March 2021

The potential of silver nanoparticles (Ag-NPs) to control plant pathogen Moniliafructicola and to deter environmental contamination by reducing fungicide doses was evaluated in vitro and in vivo.  Fungitoxicity screening of M. fructicola isolates resulted in the detection of 18 benzimidazole-resistant (BEN-R) isolates with reduced sensitivity to fungicides  thiophanate methyl (TM)  and carbendazim. All resistant isolates caried the E198A resistance mutation in their β-tubulin gene, target site of the benzimidazole fungicides. Ag-NPs could effectively control both sensitive (BEN-S) and resistant isolates while the combination of Ag-NPs with TM significantly enhanced their fungitoxic effect both in vitro and in apple fruit tests. The positive correlation observed between Ag-NPs and TM+Ag-NPs treatments indicates a mixture-enhanced Ag-NPs activity/availability as a possible mechanism of synergy. No correlation between Ag-NPs  and AgNO3 could  be found suggesting difference(s) in the fungitoxic mechanism of action between Nps and their bulk/ionic counterparts. Indications of the involvement of energy (ATP) metabolism in the mode of action of Ag-NPs were also evident by the synergy observed between Ag-NPs and the oxidative phosphorylation-uncoupler fluazinam (FM) against both BEN-R and BEN-S phenotypes. The role of silver ions release on the inhibitory action of Ag-NPs against the fungusis probably limited since the AgNPs/NaCl combination enhanced fungitoxicity, a fact that could not be justified by the expected binding of silver with chlorine ions. Concluding, Ag-NPs can be effectively used as a means of controlling both BEN-S and BEN-R M. fructicola isolates while their combination with conventional fungicides should aid anti-resistant strategies and reduce the environmental impact of synthetic fungicides by reducing effective doses to the control the pathogen.
the Development of an Annual Iceberg Calving Dataset of the Antarctic Ice Shelves 
Authors: Qi Mengzhen , Liu Yan , Cheng Xiao
Published: March 2021

  Iceberg calving, one of the key processes of Antarctic mass balance, has been regarded as an important variable in fine monitoring the changes of ice shelves. Based on multi-source satellite imagery, all annual calving events larger than 1 km² that occurred from August 2005 to August 2019 were extracted. Also, their area, thickness, mass, and calving recurrence cycle were calculated to derive the annual iceberg calving dataset. This dataset contains the distribution of 14-year annual calving events, along with the attributes of each calving event including calving year, length, area, average thickness, mass, recurrence interval, and calving type, and it can directly reflect the magnitude characteristics and distribution of Antarctic iceberg calving in different years, which fills the gap of fine monitoring dataset of iceberg calving and provides fundamental data for subsequent research on calving mechanism and mass balance of Antarctic ice shelf-ice sheet system.
Groundwater-surface water exchange: A New Graphical User Interface for temperature time-series analysis
Authors: Bertagnoli Andrea , van Berkel Matthijs , Schneidewind Uwe , van Kampen Ricky , Krause Stefan , Tranmer Andrew , Luce Charles , Tonina Daniele
Published: March 2021

Riverine systems have a dynamic exchange of water with the hyporheic zone and groundwater. Exchange fluxes can be challenging to estimate because they vary spatially and temporally and depend on many geological and hydrological properties. Temperature as a tracer has become a low-cost and robust method to monitor such fluxes both at local and reach (several channel widths) scales. Here, we present the capabilities and functionality of a new graphical user interface (GUI) developed in Python which is operating system independent. The GUI integrates standard and state-of-the-art signal processing methods with data visualization and analysis techniques. The signal analysis library allows the user to select the important frequencies to improve result confidence while the advanced LPMLEn and window function in FFT to reduce leakage in the extraction process of the amplitude and phase of the signals. The GUI streamlines the entire analysis process, from evaluating the raw temperature data to obtaining end-user specified parameters such as flux and streambed thermal properties. It allows for the analysis of single-probe and multi-probe data from short to long-term data sets.
Record high Pacific Arctic seawater temperatures and delayed sea ice advance in response to episodic atmospheric blocking
Authors: Kodaira Tsubasa , Waseda Takuji , Nose Takehiko , Inoue Jun
Published: March 2021

Arctic sea ice is rapidly decreasing during the recent period of global warming. One of the significant factors of the Arctic sea ice loss is oceanic heat transport from lower latitudes. For months of sea ice formation, the variations in the sea surface temperature over the Pacific Arctic region were highly correlated with the Pacific Decadal Oscillation (PDO). However, the seasonal sea surface temperatures recorded their highest values in autumn 2018 when the PDO index was neutral. It is shown that the anomalous warm seawater was a rapid ocean response to the southerly winds associated with episodic atmospheric blocking over the Bering Sea in September 2018. This warm seawater was directly observed by the R/V Mirai Arctic Expedition in November 2018 to significantly delay the southward sea ice advance. If the atmospheric blocking forms during the PDO positive phase in the future, the annual maximum Arctic sea ice extent could be dramatically reduced.
Spatial and Temporal Responses of Lakes in Northern Mongolia to Climate Change
Authors: Orkhonselenge Alexander , Gerelsaikhan Dashtseren , Davaagatan Tuyagerel
Published: March 2021

Lakes play a valuable role in the surface water resources of Mongolia. Understanding surface water dynamics and climate change over various spatiotemporal scales from local to regional are essential in Mongolia today. This study presents how lakes in the Mongolian Altai, Khuvsgul, and Khentii Mountain Ranges at high latitudes in northern Mongolia responded to the climate change during the past 50 years. The temporal trend shows that the lakes had extended in the area during the first three decades but reduced during the last two decades. However, Lakes Khoton and Khurgan in the Mongolian Altai and Lake Khangal in the Khentii increased in the area during 1970–2000 and since 2010, but decreased from 2000 to 2010. Lake Tolbo in the Mongolian Altai dropped in the area during 1970–2000, and continuously increased since 2000. Whereas Lakes Erkhel and Khargal in the Khuvsgul and Lake Gurem in the Khentii extended in 1970–2000 but reduced during 2000–2020. The spatial trend in lake area changes shows similar patterns for glacial lakes at an elevation above 2000 m a.s.l. in the Mongolian Altai and for tectonic and fluvial lakes at an elevation below 1500 m a.s.l. in the Khuvsgul and Khentii. Anomalies of seasonal variations in air temperature and precipitation in the lake basins show that the Lake Khangal basin in the Khentii is warmer and wetter than other lake basins. Moreover, the Lake Khargal basin in the Khuvsgul is cooler in winter and autumn but warmer in spring and summer compared to the basins. Whereas Lakes Tolbo, Khoton, and Khurgan basins in the Mongolian Altai are drier than others. The correlation analysis shows that hydrological dynamics of Lake Khargal in the Khuvsgul are strongly dependent on summer precipitation (r = 0.71), and autumn (r = 0.67) and summer (r = 0.47) air temperatures. However, the linear regression shows that the lake area is moderately related to the summer precipitation (R2 = 0.5318) and the autumn air temperature (R2 = 0.4555). Overall, the lakes in northern Mongolia show the distinct responses of hydrological dynamics to the changing climate depending on their physiographic conditions.
Automatic input variable selection for analog methods using genetic algorithms
Authors: Horton Pascal , Martius Olivia
Published: March 2021

Analog methods (AMs) are statistical downscaling methods often used for precipitation prediction in different contexts, such as operational forecasting, past climate reconstruction of climate change impact studies. It usually relies on predictors describing the atmospheric circulation and the moisture content of the atmosphere to sample similar meteorological situations in the past and establish a probabilistic forecast for a target date. AMs can be based on outputs from numerical weather prediction models in the context of operational forecasting or outputs from climate models in climatic applications.

AMs can be constituted of multiple predictors organized in different subsequent levels of analogy that refines the selection of similar situations. The development of such methods is usually a manual process where some predictors are assessed in different structures. As most AMs use multiple predictors, a comprehensive assessment of all combinations becomes quickly impossible. The selection of predictors in the application of the AM often builds on previous work and does not evolve much. However, the climate models providing the predictors evolve continuously and new variables might become relevant to be considered in AMs. Moreover, the best predictors might change from one region to another or for another predictand of interest. There is a need for a method to automatically explore potential variables for AMs and to extract the ones that are relevant for a predictand of interest.

We propose using genetic algorithms (GAs) to proceed to an automatic selection of the predictor variables along with all other parameters of the AM. We even let the GAs automatically pick the best analogy criteria, i.e. the metric that quantifies the analogy between two situations. The first test consisted of letting the GAs select the single best variable to predict daily precipitation for each of 25 selected catchments in Switzerland. The results showed great consistency in terms of spatial patterns and the underlying meteorological processes. Then, different structures were assessed by varying the number of levels of analogy and the number of variables per level. Finally, multiple optimizations were conducted on the 25 catchments to identify the 12 variables that provide the best prediction when considered together.
Global networks of underground research – Geoinformatics in exploring the interaction between laboratories and research units by geocoded publication metadata
Authors: Kotavaara Ossi , Joutsenvaara Jari , Puputti Julia , Niinikoski Eija-Riitta , Heinikoski Ursula , Martinmäki Pertti
Published: March 2021

Globally there are more than 75 identified scientific underground facilities or laboratories. Underground laboratories or underground research mines are related to 400.000 scientific publications in the Web of Science since 1975. Underground laboratories are commonly located in operational or closed mines, tunnel systems, or built for this specific purpose. It is clear that a wide variety of disciplines and research units apply these facilities. However, it is unclear what is the thematic distribution in research by laboratories at a global scale, or what is the geographic distribution of the scientific communities applying the facilities? In practice, do, e.g. political borders or distance play a role in this?

Understanding prevailing and potential market areas of underground laboratories and research mines for research communities applying these facilities are key elements in developing the use and utilisation of such facilities. Again, it is important to get a better knowledge of the structures, networks, and thematic emphasise of these research communities to understand their requirements and expectations for the underground research infrastructures. This study aims to deepen the knowledge in this field by geocoding teams and units published research, which applied underground facilities. Geographic information systems (GIS) and geocoding functions are applied to build a network between underground laboratories and research teams using all recognised underground research from the web of knowledge. Preliminary analysis indicates that underground laboratories may have a large global scientific user network, but the relatively active network of a few key partner institutes.

The research is supported by the Interreg Baltic Sea programme funded  Empowering Underground Laboratories network usage – EUL and the Baltic Sea Underground Innovation Network (BSUIN) projects.
Harmonizing heterogeneous multi-proxy data from Arctic lake sediment records 
Authors: Pfalz Gregor , Diekmann Bernhard , Freytag Johann-Christoph , Biskaborn Boris K.
Published: March 2021

Lake systems play a central role in broadening our knowledge about future trends in the Arctic, as their sediments store information on interactions between climate change, lake ontogeny, external abiotic sediment input, and biodiversity changes. In order to make reliable statements about future lake trajectories, we need sound multi-proxy data from different lakes across the Arctic. Various studies using data from repositories already showed the effectiveness of multi-proxy, multi-site investigations (e.g., Kaufman et al., 2020; PAGES 2k Consortium, 2017). However, there are still datasets from past coring expeditions to Arctic lake systems that are neither included in any of these repositories nor subject to any particular standard. When working with such data from heterogeneous sources, we face the challenge of dealing with data of different format, type, and structure. It is therefore necessary to transform such data into a uniform format to ensure semantic and syntactic comparability. In this talk, we present an interdisciplinary approach by transforming research data from different lake sediment cores into a coherent framework. Our approach adapts methods from the database field, such as developing entity-relationship (ER) diagrams, to understand the conceptual structure of the data independently of the source. Based on this knowledge, we developed a conceptual data model that allows scientists to integrate heterogeneous data into a common database. During the talk, we present further steps to prepare datasets for multi-site statistical investigation. To test our approach, we compiled and transformed a collection of published and unpublished paleolimnological data of Arctic lake systems into our proposed format. Additionally, we show our results from conducting a comparative analysis on a set of acquired data, hereby focusing on comparing total organic carbon and bromine content. We conclude that our harmonized dataset enables numerical inter-proxy and inter-lake comparison despite strong initial heterogeneity.

 

[1]   D. S. Kaufman et al., “A global database of Holocene paleotemperature records,” Sci. Data, vol. 7, no. 115, pp. 1–34, 2020.

[2]   PAGES 2k Consortium, “A global multiproxy database for temperature reconstructions of the Common Era,” Sci. Data, vol. 4, no. 170088, pp. 1–33, 2017.
Early results for the STIX image reconstruction problem: imaging from visibility amplitudes
Authors: piana michele , massa paolo , perracchione emma , battaglia andrea francesco , benvenuto federico , massone anna maria , hurford gordon , krucker sam
Published: March 2021

The Spectrometer/Telescope for Imaging X-rays (STIX) is the instrument of the Solar Orbiter mission conceived for the observation of the hard X-ray flaring emission, with the objective of providing insights on the diagnosis of thermal and non-thermal accelerated electrons at the Sun. The STIX imaging system is composed of 30 pairs of tungsten grids, each one placed in front of a four-pixel detector, and produces as many Fourier components of the angular distribution of the flaring source, via Moiré pattern modulation. Therefore, the data recorded by STIX, named visibilities, can be interpreted as a sparse sampling of the Fourier transform of the X-ray signal and the corresponding image reconstruction problem requires the inversion of the Fourier transform from limited data, usually addressed with regularization techniques. Since the current calibration status of STIX measurements still prevents the use of visibility phases for imaging purposes, here we propose a parameter identification process based on forward fitting  just the amplitude of the experimental visibilities. Specifically, we have parameterized the flaring source by means of pre-assigned source shapes (e.g., circular and elliptical bi-variate Gaussian functions), and we relied on several approaches to non-linear optimization in order to estimating the shape parameters. In particular, we have implemented a forward-fit method based on deterministic chi-squared minimization, a stochastic optimization algorithm and a deep neural approach based on ensemble learning, also equipping them with an ad hoc statistical technique for uncertainty quantification. The performances of the three approaches are compared in the case of both microflares and M class events recorded by STIX during its commissioning phase and the validation of results is realized also exploiting the EUV information provided by the Atmospheric Imaging Assembly within the Solar Dynamics Observatory.
Global reorganization of atmospheric circulation during Dansgaard-Oschger cycles
Authors: Fohlmeister Jens , Sekhon Natasha , Columbu Andrea , Rehfeldt Kira , Sime Louise , Veige-Pires Cristina , Marwan Norbert , Boers Niklas
Published: March 2021

Ice core records from Greenland provide evidence for multiple abrupt warming events recurring at millennial time scales during the last glacial interval. Although climate transitions strongly resembling these Dansgaard-Oeschger (DO) transitions have been identified in several speleothem records, our understanding of the climate and ecosystem impacts of the Greenland warming events in lower latitudes remains incomplete.

Here, we investigate the influence of DO transitions on the global atmospheric circulation pattern. We comprehensively analyse d18O changes during DO transitions in a globally distributed dataset of speleothems (SISALv2; Comas-Bru et al., 2020). Speleothem d18O signals mostly reflect changes in precipitation amount and moisture source. Thereby this proxy allows us to infer spatially resolved changes in global atmospheric dynamics that are characteristically linked to DO transitions. We confirm the previously proposed shift of the Intertropical Convergence Zone towards more northerly positions. In addition, we find evidence for a similar northward shift of the westerly winds of the Northern Hemisphere. Furthermore, we identify a decreasing trend in the transition amplitudes with increasing distances from the North Atlantic region. This confirms previous suggestions of this region being the core and origin of these past abrupt climate changes.

 

References:

Comas-Bru et al., 2020, Earth System Science Data 12, 2579–2606

 
Potential of peatland restoration in Germany – a nationwide landscape analysis
Authors: Koppensteiner Wiltrut , Wegmann Johannes , Tiemeyer Bärbel
Published: March 2021

Peatland restoration projects are important to mitigate climate change, loss of biodiversity and sustain and develop ecosystem services of peatlands. National and global strategies which address the effects of peatlands on climate change and nature conservation as well as the social and economic compatibility of peatland restoration projects are needed. The regional focus of these strategies is crucial for prospective restoration projects as well as for the measurements used to identify regions with high potential for realisation of peatland restoration along with sufficient impact on GHG reduction and nature conservation.

Therefore, we aim to identify regions in Germany in which the potential of realisation of restoration projects is high. Further, we identify important restrictions at regional scale which hinder potential peatland restoration projects.

We assembled a set of regional indicators and analysed the available GIS-data on the nationwide scale of Germany. Indicators comprise natural (e.g. precipitation surplus), legislative (e.g. protected and priority areas) and economic (e.g. land use, marginal return) conditions. Each identified indicator was categorised based on its relevance for the feasibility of implementing peatland restoration projects. Using landscape structure analyses, regions throughout Germany with good prospective for the realisation of peatland restoration projects were identified. These highlighted regions show high potential for optimising and/ or maximising the ecosystem services of peatlands. To characterise the region based on the indicators used, short profiles were created for each resulting region. We recommend to take the analysing method and these highlighted regions into account when developing nationwide strategies for peatland management in Germany.
Modeling winter season fluxes of water and energy in a temperate montane forest
Authors: Vogel Tomas , Dohnal Michal , Votrubova Jana , Dusek Jaromir , Tesar Miroslav
Published: March 2021

Winter regimes affect significantly the long-term water and energy balance of mountainous areas in Central Europe. A recently developed numerical model is used to study near-surface fluxes of water and energy in the Liz catchment — a small headwater catchment of the Otava River, situated in the Southern Bohemia. The results of the numerical simulations are compared with high-resolution data recorded at the site of interest. The forest floor of the catchment is mostly covered by snow during winter. However, the snowpack is usually exposed to several snowmelt episodes over the season. The intensity, duration and frequency of these episodes is irregular and seems to be highly sensitive to changing climate. Increasing frequency of winter periods with limited or missing snow cover affects both water flow and heat transport in the catchment. Changes in the temporal distribution of snowmelt are reflected in changing runoff patterns.

 
A global EMOS postprocessing for temperature and precipitation forecasts for any location in Switzerland
Authors: Rajczak Jan , Regula Keller , Jonas Bhend , Stephan Hemri , Lionel Moret , Christoph Spirig , Mark A. Liniger
Published: March 2021

MeteoSwiss is developing and implementing a post-processing suite of multi-model ensemble forecasts to produce seamless probabilistic calibrated forecasts at arbitrary locations in Switzerland (i.e. also for un-observed locations). With the complex topography of Switzerland, the raw output of the numerical model is subject to particular strong biases and conditional errors. Here, we present results for hourly temperature and precipitation predictions.

We apply a global ensemble model output statistics (gEMOS) framework. It extends the classical EMOS approach by incorporating static predictor variables describing relevant topographical features and it is trained for all stations together using a 4-year multi model numerical weather prediction (NWP) archive. As NWP sources, we combine data from the COSMO model suites (1.1 and 2.2 km horizontal grid-spacing) and from the ECMWF IFS medium-range forecasting system. Note that the three NWP suites have different forecast horizons.
We show that gEMOS is able to improve forecasts for both variables. Depending on selection of predictors, lead-time, hour-of-day and season we find improvements up to 30% in terms of CRPS for both variables with most pronounced improvements in mountainous regions. Particularly for temperature, the multi-model combination further increases the forecast skill compared to postprocessing using high-resolution simulations of COSMO only.

While locally optimized approaches show better performance in terms of skill at the observing sites, the advantage of gEMOS lies in the ability to generate calibrated predictions for arbitrary locations in a consistent way. Its computational efficiency makes it a particularly attractive method for operationalization in a realtime context.
MORGEN – The Mid Ocean Ridge GENerating algorithm
Authors: van der Linden Thomas , van Hinsbergen Douwe
Published: March 2021

Paleo-digital elevation models (paleoDEM) based on plate tectonic and paleogeographic reconstructions use age grids of ocean floor to determine ocean bathymetry. In recent years, such age grids have also been developed for now-subducted oceans from the far geological past, as far back as the Neoproterozoic, using geology and paleomagnetism-based estimates of ocean opening. In such reconstructions, mid ocean ridges are drawn based on estimated Euler poles and rotations, and conceptual knowledge on the geometry consisting of spreading ridges and transform faults.

Current procedures to draw mid ocean ridges in plate tectonic reconstructions are laborious, as new ridges are drawn every time the Euler pole location changes. Fortunately this is also a task that can be automated. We have written an algorithm using pyGPlates that takes as input a smooth curve at the approximate position of the reconstructed mid ocean ridge at the moment of its formation, and then calculates spreading and transform segments according to their typical geometries in modern oceans, assuming symmetric spreading. The algorithm allows gradual readjustment of ridge orientations upon Euler pole changes comparable to documented cases in the modern oceans (e.g., in the Weddell Sea). The algorithm also contains modules that can convert the calculated mid ocean ridges with other plate boundaries to boundary topologies – which can be used as input for the recently published TracerTectonics algorithm, produce isochrons which can be converted to age grids, check for subduction of isochrons and subsequently create bathymetry grids. We illustrate the use of the MORGEN algorithm with recently published reconstructions of subducted, as well as future oceans.
The Atlantic Multidecadal Oscillation controls the impact of the North Atlantic Oscillation on North European climate
Authors: Börgel Florian , Frauen Claudia , Neumann Thomas , Meier H. E. Markus
Published: March 2021

European climate is heavily influenced by the North Atlantic Oscillation (NAO). However, the spatial structure of the NAO is varying with time, affecting its regional importance. By analyzing an 850-year global climate model simulation of the last millennium it is shown that the variations in the spatial structure of the NAO can be linked to the Atlantic Multidecadal Oscillation (AMO). The AMO changes the zonal position of the NAO centers of action, moving them closer to Europe or North America. During AMO+ states, the Icelandic Low moves further towards North America while the Azores High moves further towards Europe and vice versa for AMO- states. The results of a regional downscaling for the East Atlantic/European domain show that AMO-induced changes in the spatial structure of the NAO reduce or enhance its influence on regional climate variables of the Baltic Sea such as sea surface temperature, ice extent, or river runoff.
Potential agricultural soil carbon sequestration across Europe: a reality check
Authors: Rodrigues Leonor , Hardy Brieuc , Huyghebaert Bruno , Leifeld Jens
Published: March 2021

To meet the Paris Agreement goal of limiting average global warming to less than 1.5°C above pre-industrial temperatures, European Union (EU) aims to reduce by 40% its domestic greenhouse gas (GHG) emissions by 2030 and in the longer term to become the world’s first climate-neutral economy by 2050 (“Green Deal”). Today, 10% of the European GHG emissions derive directly from agriculture, and measures to decrease or compensate these emissions are required for achieving climatic goals. The role of soils in the global carbon cycle and the importance of reducing GHG emissions from agriculture has been increasingly acknowledged (IPCC, 2018, EEA report 2019). The “4 per 1000” initiative (4p1000) has become a prominent model for mitigating climate change and securing food security through an annual increase in soil organic carbon (SOC) stocks by 0.4 %, or 4‰ per year, in the first 0-40 cm of soil. However, the feasibility of the 4p1000 scenario and more generally the capacity of European countries to implement soil carbon sequestration (SCS) measures are highly uncertain.

As part of the EJP Soil project, we collected country-specific informationonon on the available knowledge and data of achievable carbon sequestration in mineral agricultural soils (cropland and grassland) across Europe, under various farming systems and pedo-climatic conditions. With this bottom-up approach, we provide a reality check on weather European countries are on track in relation to GHG reductions targets and the “4p1000” initiative. First results showed that the availability of datasets on SCS is heterogeneous across Europe. While northern Europe and central Europe is relatively well studied, references are lacking for parts of Southern, Southeaster and Western Europe. Further, this stocktake highlighted that the current country-based knowledge and engagement is still poor; very few countries have an idea on their national-wide achievable SCS potential. Nevertheless, national SCS potentials that were estimated for 13 countries support the view that SCS can contribute significantly to climate mitigation, covering from 1 to 28, 5 % of the domestic GHG emissions from the agricultural sector, which underpins the importance of further investigations.
Rainwater isotopes in central Vietnam controlled by two oceanic moisture sources and rainout effects
Authors: Wolf Annabel , Roberts William H. G. , Ersek Vasile , Johnson Kathleen R. , Griffiths Michael L.
Published: March 2021

Oxygen isotopes are commonly used proxies in paleoclimate research, however, a correct interpretation requires a detailed understanding of processes controlling isotope variability for a specific site.  A common interpretation for oxygen isotopes in precipitation across the Asian monsoon region, links the seasonal and interannual variability to changes in the summer monsoon strength.

However, some locations within tropical Asia do not receive rainfall during the summer monsoon season. In central Vietnam most of the annual rainfall falls during autumn instead of summer, making central Vietnam ideal to investigate processes controlling rainwater isotope variability, independent from the summer monsoon. By using rainwater isotopes, collected over five years, and moisture uptake simulations for these time periods, we investigate the seasonal cycle and interannual variability of hydrological processes in central Vietnam.

Our results show that the seasonal variability is dominated by a shift in moisture source from the Indian Ocean in summer to the South China Sea (western Pacific) from autumn to spring. The different source locations are reflected by an increase in δ18O values from around − 8 to − 10‰ during summer to values between 0 and − 3‰ during winter/spring. Further, we show that the amount effect and the occurrence of tropical cyclones, which are typical for the region, have no effect on a seasonal to interannual scale. Instead, we find that the timing of the seasonal ITCZ migration is a driving component of variability on these time scales.
Seasonal variability of the Rossby radius deformation in the Hornsund fjord
Authors: Przyborska Anna , Rak Daniel , Strzelewicz Agnieszka , Jakacki Jaromir , Muzyka Maciej
Published: March 2021

The Earth's rotation affects the water circulation in the Arctic fjords. It can be described by means of the baroclinic Rossby radius deformation (R1) expressed as the ratio of the internal wave velocity to the Coriolis parameter.

The influence of the rotational effects on the water‐mass distribution depends on the width of the fjord in relation to the baroclinic radius of deformation (Gilbert, 1983). Most often the Rossby radius deformation in the Arctic fjords is 2-3 times smaller than the width of the fjord entrance, which allows the rotation of water masses within such fjords (Cottier, 2010). Such a situation exists in the small, western fjord of Svalbard - Hornsund, where the rotation makes the Atlantic and the Arctic waters flow from the shelf into the fjord along the southern bank and flow out of the fjord along the northern bank. The impact of the Coriolis force on the Hornsund environment was observed in a sedimentary record from the last century (Pawłowska et al. 2017). Literature estimates indicate that Hornsund is a typical fjord with an internal baroclinic Rossby radius between 3.5 and 6 km (Cottier, 2005, Nilsen, 2008).

The spatial and seasonal variation of the R1 in the Hornsund fjord was carried out based on data from the numerical model (Jakacki et al. 2017) for the period 2005-2010 and for the selected actual data collected during the AREX survey campaigns.  The analysis of the actual data and model data confirms the seasonal variability of the vertical water structure in the fjord, which leads to cyclic changes of the vertical Brunta-Vaisali frequency structure and consequently to seasonal variability of R1. In the Hornsund fjord seasonality strongly influences the Rossby radius, which reaches maximum values in summertime and minimum values in wintertime. Moreover, R1 values can be different even at points close to each other.  The values of the baroclinic Rossby radius of deformation also differ depending on the adopted calculation method.

Calculations were carried out at the Academic Computer Centre in Gdańsk.

 

 
Simulating streamflow in a temporary karst river system
Authors: Ricci Giovanni Francesco , Centanni Marco , Gentile Francesco , De Girolamo Anna Maria
Published: March 2021

Most of the basins in the Mediterranean Region are characterized by a large spatial gradient in rainfall and temperature and heterogeneity in lithology, soil, and land use. Such environmental factors determine a specific hydrological regime of the river systems that generally includes periods of absence of flow and flash flood events.

In the past decades, several countries in South Europe did not invest resources for the monitoring of the intermittent river systems. Currently, several basins have limited time series of streamflow and water quality data. In addition, it is not rare the case of climate stations not well distributed in the basin as well as the presence of several gaps in the time series.

The lithology and geological features are among the main factors affecting the flow regime, playing a crucial role in groundwater and surface-water interaction and water exchange for which the flow may appear and disappear along with the river network. In such a complex environment, the hydrological and water quality model set up and run may be challenging.

Through a case study, this work aims to face some challenges and to define problem-solving in simulating hydrology in Mediterranean basins. The area is characterized by (i) heterogeneity in lithology with karst areas, (ii) limited flow data availability for calibrating the model, (iii) flow intermittence in the river network. The Soil and Water Assessment Tool (SWAT) was applied to the Canale D’aiedda  (Puglia, Italy), a temporary karst river basin under the Mediterranean climate and with limited data availability. Different solutions were tested to simulate the hydrological processes in the karstic areas including both GIS elaborations and model parameters settings and modifications. Among the main parameters, infiltration and transmission losses and soil hydraulic parameters resulted in the most relevant in simulating hydrology in the karst areas. To calibrate the model, a split-in-space procedure was adopted to overcome the limited streamflow measurement availability. Finally, a zero-flow threshold was introduced to predict the number of zero-flow days in the intermittent river reaches, simulating accurately the flow intermittence and the extreme low flow.

The results show that by using specific strategies in setting-up and calibrating the model, the SWAT model is able to simulate daily streamflow with acceptable performances in complex river basins.
Potential hydro-meteorological impacts over Burundi from climate change
Authors: Rivas López María del Rocío , Liersch Stefan , Hattermann Fred Fokko
Published: March 2021

Burundi is one of the poorest countries in the world with about 65% of the population living below the poverty line and suffering from alarming food insecurity. Its population is highly dependent on rain-fed agriculture, which makes them extremely sensitive to climate variability and extremes for their subsistence. During the last decades, heavy rains, floods, and landslides suffered by Burundi’s population have led to severe famines, death, conflicts, and internal displacement among other fatalities, indicating the high vulnerability of this region to extreme events. Therefore, it is of vital importance to provide detailed information about the potential impacts of climate change in order to enhance adaptation options and preparedness in a country for which little information about climate projections and hydro-climatic impacts is available.

In this work, we investigated the changes in future climate over Burundi projected by a set of 13 regional climate models, for two future periods, under RCP4.5 and RCP8.5. The projections from CORDEX models have been used as forcing climate for the eco-hydrological Soil and Water Integrated Model (SWIM) in order to assess future changes in mean and extreme river discharge and water availability across Burundi.

Our results indicate that unabated climate change will lead to faster and more severe warming over Burundi than the global mean. Precipitation will increase in the north of Burundi despite a possible prolongation of the dry season, and will decrease in the south, with the exception of the months core of the rainy season that show the highest rise along the year and across the country. <!-- Option 2.
#Two different signals of change were found for future long-term annual mean precipitation in North (+) and South (-) Burundi. Higher increases would take place in the months core of the rainy season in the whole region, while the north may experience a prolongation of the dry season. -->The increase in the frequency, magnitude, and intensity of extreme climate events (daily temperature, dry and wet events) will characterize the future climate in this region according to CORDEX models.

These changes get translated into increases of discharge in North Burundi across the whole year in all future scenarios and periods (up to 196% in annual streamflow in small catchments and 40% in larger ones), and slight decreases in the south from February to October (up to 7%). The increase of daily and annual extreme river discharges, their probabilities of exceedance, and the decrease in their recurrence intervals implies a higher risk of floods in magnitude and frequency.

These findings indicate the critical importance of adaptation of land and water management to changing hydro-climatic conditions in Burundi to improve food security and support its development.
Machine learning based conditional mean filter: a non-linear extension of the ensemble Kalman filter 
Authors: Hoang Truong-Vinh , Krumscheid Sebastian , Tempone Raul
Published: March 2021

Filtering is an uncertainty quantification technique that refers to the inference of the states of dynamical systems from noisy observations. This work proposes a machine learning-based filtering method for tracking the high-dimensional non-Gaussian state-space models with non-linear dynamics and sparse observations. Our filter method is based on the conditional expectation mean filter and uses machine-learning techniques to approximate the conditional mean (CM). The contribution of this work is twofolds: (i) we demonstrate theoretically that the assimilated ensembles obtained using the ensemble conditional mean filter (EnCMF) provide a correct prediction of the posterior mean and have the optimal variance, and (ii) we implement the EnCMF using artificial neural networks, which has a significant advantage in representing non-linear functions that map between high-dimensionality domains, such as the CM. We implement the machine learning-based EnCMF for tracking the states of the Lorenz-63 and 96 systems under the chaotic regime. Numerical results show that the EnCMF outperforms the ensemble Kalman filter.
Historical changes in fresh water transport from sub-tropical to sub-polar oceans
Authors: Sohail Taimoor , Zika Jan , Irving Damien , Church John
Published: March 2021

Warming-induced global water cycle changes pose a significant threat to biodiversity and humanity.  The atmosphere transports freshwater from the sub-tropical ocean to the tropics and poles in two distinct branches. The resulting air-sea fluxes of fresh water and river run-off imprint on ocean salinity (S) at different temperatures (T), creating a characteristic `T-S curve' of mean salinity as a function of temperature. Using a novel tracer-percentile framework, we quantify changes in the observed T-S curve from 1970 to 2014.  The warming ocean has been characterised by freshening tropical and sub-polar oceans and salinifying sub-tropical oceans. Over the 44 year period investigated, a net poleward freshwater transport out of the sub-tropical ocean is quantified, implying an amplification of the net poleward atmospheric freshwater transport. Historical reconstructions from the 6th Climate Model Intercomparison Project (CMIP6) exhibit a different response, underestimating the peak salinification of the ocean by a factor of 4, and showing a weak freshwater transport into the sub-polar ocean. Results indicate this discrepancy between the observations and models may be attributed to consistently biased representations of evaporation and precipitation patterns, which lead to the the weaker amplification seen in CMIP6 models.
Buffering Capacities in Mediterranean soils under different soil management
Authors: Hueso González Paloma , Dvořáčková Helena , Hladký Jan , Vlček Vítězslav
Published: March 2021

Dryland areas are being seriously affected by degradation processes. The use of organic amendments in ecosystem restoration is an effective technique for accelerating soil regeneration processes in degraded drylands. The goal of this paper is to establish the effect of application of various organic amendments to degraded soil, on soil buffering capacity after 10 years. Buffering capacity is an important indicator, which is evidence of the overall condition of the soil ecosystem and influences a whole range of other soil properties, because buffering in soil is defined as the resistance of the soil to variations in pH. The experiment was carried out at the location called El Pinarillo in the Sierra de Tejeda, Almijara and Alhama Natural Park (southern Spain). The site is located at 470 m a.s.l., in the upper part of an alluvial fan (calcareous conglomerates). The experiment treatments were natural soil, bare soil, hydropolymers, pinus mulch, prescribed burnt, Sewage sludge. Application of hydrogel had the smallest effect on buffering capacity 10 years after application and manifested as just a slight decrease in soil buffering capacity while maintaining or improving other soil properties. The good buffering capacity of this variant also allows further work with the specific soil without greater risk of further degradation. Sludge was identified as the worst variant, whereas soil buffering capacity fell markedly, because sewage sludge may significantly inhibit microbial activity and decomposition of organic matter. This variant is not suitable for further use, because there is a risk of further soil degradation.
MarsSI: Martian surface data processing service 
Authors: Volat Matthieu , Quantin-Nataf Cathy , Thollot Patrick , Mandon Lucia
Published: March 2021

MarsSI is a platform to help find and process Mars orbital data. Originaly developed in the context of the e-Mars project (2012-2017) funded by the European Research Council, it was certified in 2017 as french national Research Infrastructure by the Centre National de la Recherche Scientifique (CNRS) as part of the Planetary Surface Portal (PSUP) [2].

MarsSI client interface is a web application. The user is provided a map based interface where available products are displayed as footprints. The user can browse and select data from here. A workspace view, allows the user to better review product selection individually. This is also the view where user will be able to request dataset processing.

All MarsSI proposed pipelines are fully automated and do not require user parametrization. This allows us to keep our global catalog reasonable and have only one version of a single product at a time, that is shared between all users. To retrieve a product, the user will request a copy operation to its home directory, where it will be available for 30 days through SFTP access (the product is kept can be copied again after this).

As of 2021, MarsSI indexes and give access to the optical data (visible, multi and hyperspectral) and derived products from three missions: Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter. Our emphasis was to provide ”ready-to-use” products in regards of calibration, refinements and georeferencing. The user will be able to visualize and interpret the data in GIS or remote sensing software.

MarsSI provides access to various optical datasets for visible, multi- and hypespectral data from the various martian orbital missions over the years. We also offer multiple Digital Elevation Model (DEM) datasets. Some of them are provided from external sources (such as those provided by the HiRISE and HSRC teams). But users can also requests med- and high-resolution DEMs generated using the Ames Stereo Pipeline software that are computed on our platform using a custom developed workflow.

MarsSI is open to the world­ wide scientific community. As of december 2020, we count 215 registered users across 128 institutes. Since it is a french service, 25% of the users are from France, but we also offer data to scientists from the USA, UK, India and China.

Built upon opensource frameworks and using standardized protocols, MarsSI offers the scientific communities an easy way to process data, most notably DEMs that can be derived from CTX and HiRISE data collection.