bluuebunny/crossref_metadata_2025 huggingface dataset:
Solar cycle variation of simple and complex active regions
Authors: Nikbakhsh Shabnam , Tanskanen Eija , Käpylä Maarit , Hackman Thomas
Published: March 2020

Solar active regions (ARs) emerge on the Sun’s photosphere and they frequently produce flares and coronal mass ejections which are among major space weather drivers. Therefore, studying ARs can improve space weather forecast.

The Mount Wilson Classification has been used since 1919 in order to group groups ARs according to their magnetic structures. In this study, we investigated the magnetic classification of 4797 ARs and their cyclic variation, using our daily approach for the period of January 1996 to December 2018.

We show that the monthly number of the simple ARs (SARs) attained their maximum during first peak of the solar cycle, whereas more complex ARs (CARs) reached their maximum roughly two years later, during the second peak of the cycle. We also demonstrate that the total abundance of CARs is very similar during a period of four years around their maximum number. We also studied the latitudinal distributions of SARs and CAR in northern and southern solar hemispheres and show that the independent of the complexity type, the distributions are the same in both hemispheres.

Furthermore, we investigated the earlier claim of increase in number of CARs due to the decrease in ARs latitudinal band. Here we show that, contrary to this claim, CARs attained their maximum number before the latitudinal band started to decrease in both northern and southern hemispheres.
Phosphorus chemical changes under soils over a period of agricultural intensification
Authors: Tweedie Andrew , Haygarth Philip M. , Edwards Anthony , Lilly Allan , Baggaley Nikki , Stutter Marc
Published: March 2020

The use of phosphorus (P) fertilizer has been one of the defining contributors to productive agriculture since the green revolution during the middle of the last century. However, these increased yields have come at the cost of dependency upon the declining resources of P rock reserves and eutrophication of water bodies downstream. In this context, it is important to understand the long-term effects of these P fertilizer additions on soil chemistry over ~50 years in order explain past and current patterns in fertilizer usage and so to better inform future soil management.

We tested the hypothesis that phosphorus forms and availability in mixed use (arable and grazed) agricultural soil have changed over a period of 50 to 80 years of agricultural intensification. Spatially matched samples of soil from 34 agricultural sites in North East (NE) Scotland were collected at two timepoints. The first samples were taken between 1951 and 1981 and in all cases the resampling took place in the autumn of 2017. The soils sampled were representative of agricultural soils in NE Scotland.

The hypothesis was tested by employing a range of soil tests on the ‘old’ and ‘new’ time points.  These included water extraction for inorganic and organic P, nitrate and ammonium and dissolved organic carbon, acid ammonium oxalate extraction to investigate the soil P exchange complex and NaOH-EDTA extraction as a strong alkaline extractant which preserves organic P forms. Analysis by 31P NMR was conducted on the NaOH-EDTA extracts from 5 pairs of samples, to investigate the organic P chemistry of in greater detail.

Phosphorus concentrations for stronger extractants (NaOH-EDTA, acid ammonium oxalate) did not increase significantly (P<0.05) over time. However, water extraction results showed increases in total P (P<0.01) and inorganic P but decreases in organic P. Additionally, analysis by 31P NMR detected changes between timepoints in α-glycero-phosphate and pyrophosphate.

These results indicate that differences in the various chemical forms of P present in soil between the timepoints can be detected many decades apart. This indicates changes in the functioning of the P cycle in these soils under intensive agricultural land use over time. Knowledge of the P-cycling response of soils under agricultural land-use over decades provides an opportunity to understand changes in soil nutrient concentrations, balances and availability and inform studies seeking to improve the sustainable management of soil fertility.
Satellite based estimation of atmospheric wakes downstream offhore windparks using a new objective filter technique
Authors: Schulz-Stellenfleth Johannes , Djath Bughsin , Haid Verena
Published: March 2020

The large number of already existing and planned offshore wind parks in the German Bight leads to challenging requirements with regard to reliable information on various processes in the atmosphere and the ocean. In particular wind shadowing effects play a major role for the optimal planning and operation of wind park installations. Synthetic Aperture Radar (SAR) satellites have proved their capability of giving a 2D view of the wakes generated behind wind farms at a  high spatial resolution. However, the estimation of wind speed deficits from SAR data is still a challenge, because undisturbed reference wind fields are usually not available at the exact location of the wake. A common approach is therefore to identify some reference areas on SAR scenes outside the wake region, which naturally leads to errors in the deficit computations. 
In this study a new filter approach for the deficit estimation is proposed, which allows to derive error bars for the deficits. The filter is based on a 2D convolution operation with a filter kernel, which has a shape depending on the wind park geometry and the wind direction. The errors depend on spectral properties of the background wind fields, which are estimated from SAR data as well. In this context the stability of the atmospheric boundary layer is shown to play a major role. Examples are shown using data acquired by the SENTINEL-1A/B satellites. The approach is seen as a contribution to make SAR based deficit computations more objective and automised, which is essential for the application of the method to larger data sets and to make wake analysis done in different regions more comparable.
Topical Cyclone Convection Structure Evolution during Rapid Intensification using Himawari-8 Satellite
Authors: Zhang Da , Zhang Jiahua
Published: March 2020

Rapid intensification process (RI) still challenges the tropical cyclone (TC) intensity prediction. The convective structure evolution during RI process were explored by using the Himawari-8 satellite data in the western North Pacific. 39 TCs underwent at least one RI process during 2015-2017 and the RI-onset, RI-continue, and RI-end episodes were identified in each one of the RI events based on JTWC best track data.

The differences between the infrared channel and water vapor channel brightness temperature (IRWV) were calculated and the negative pixel values of IRWV were considered as deep convection areas. The radial and azimuthal profiles and the morphological features were extracted from 3-hour interval images and several key patterns and the rules considering the location, shapes, and magnitude of the IRWV were identified through the whole RI process. The composite analysis shows that each TC appears negative IRWV during the RI process, however, not all TCs demonstrate significant changes either in areas nor patterns, which indicate that the deep convection may not be a necessary condition for RI occurrence. Compared with the Non-RI cases, the development and maintenance of a good spin structure of the negative IRWV were considered as a crucial condition for the TC intensification. The RI-onset periods were mostly connected with the sudden change of IRWV and the inward movement to the inner-core area. The pinhole eye features were normally a sign of continue RI, while the appearance of big eye features, indicates the ending of RI process. It was suggested that the IRWV feature combined with the TC structure feature can be utilized to skillfully predict the episodes of RI. More RI events are expected to involved in the current study and a CART4.5 decision tree algorithm with the aforementioned rules was also under explored.
Monitoring the Greenland Ice Sheet: A comparison between Sentinel-3 and CryoSat-2 radar altimeters
Authors: Maddalena Jennifer , Dawson Geoffrey , Chuter Stephen , Landy Jack , Bamber Jonathan
Published: March 2020

Since 1992, satellite-borne radar altimetry has been used to record surface elevation change over the Greenland ice sheet (GrIS). Until the launch of CryoSat-2 in 2010, conventional radar altimeters performed poorly over high sloping terrain with heterogenous topography. The novel synthetic aperture radar interferometric (SARIn) mode of CryoSat-2 has improved capability in these regions over the margins of the GrIS, which have been experiencing the largest mass loss. ESA’s Sentinel-3 mission is the latest radar-altimeter to be launched. The first satellite, Sentinel-3A, was launched in February 2016 followed by Sentinel-3B April 2018. The Sentinel-3 satellites are the first to use synthetic aperture radar (SAR) across the interior of the GrIS. This has improved the along-track resolution to approximately 300m compared to CryoSat-2’s Low Resolution Mode (LRM) footprint which has a diameter of ~1.65km.

Here we assess the performance of Sentinel’s SAR mode compared to the LRM mode of CryoSat-2 over the interior of the ice sheet and the SARIn mode over the margins of the GrIS, through crossover analysis and a point-to-point comparison. We then assess the implications of this comparison for monitoring elevation changes over the ice sheet and we present rates of elevation change for June 2016 - June 2019 for both radar altimeter missions. To calculate rates of volume change from elevation change we use a statistical interpolation method, universal kriging, and present volume changes per basin over Greenland before comparing volume change estimates between CryoSat-2 and Sentinel-3.
Shallow landslides involving weathered and fractured bedrock: a comparative susceptibility analysis between deterministic and statistical models
Authors: D'Addario Enrico , Disperati Leonardo , Zêzere José Luís , De Melo Raquel , Oliveira Sérgio
Published: March 2020

Shallow landslide susceptibility modelling at regional scale may be performed using both a physically based and statistical approach. For the same area, these two approaches can have inconsistent results, mainly because the two methods are conceptually different. Physically based models are based on the infinite slope model and consists on the computation cell by cell of a safety factor comparing between driving and resisting forces. The assumption that landslides occur in slopes that are characterized by predisposing factors similar to those in which landslides have occurred in the past, is the concept behind the statistical models. The aim of this work is to compare the two approach and investigate the differences between the two models. The study area is located in northern Tuscany, central Italy, in which an extensive field survey highlighted that about 60% of landslides involve bedrock. For this reason, we developed a physically based susceptibility analysis taking into account both the surficial layer (slope deposit, SD) and the underlying layer (BR), characterized by weathered and fractured bedrock. This model is compared to the statistically based one, which take into account topographic and geologic predisposing factor as well as bedrock geo-mechanical properties, such Geological Strength Index (GSI), Schmidt hammer rebound values (Rv) and Joint density (Jv). The accuracy of the models is evaluated using a multi-temporal landslide inventory, in which involving bedrock landslides are distinct from slope deposits landslides. Within this general framework results are discussed regarding the model’s predictive capacity and spatial agreement.
It's impolite to zoom in on global hydrological models
Authors: Aerts Jerom , Weerts Albrecht , van Verseveld Willem , Drost Niels , Hut Rolf , van de Giesen Nick
Published: March 2020

Large scale or global hydrological models (GHMs) show promise in enabling us to accurately predict floods, droughts, navigation hazards, reservoir operations, and many more water related issues. As opposed to regional hydrological models that have many parameters that need to be calibrated or estimated using local observation data (Sood and Smakhtin 2015). GHMs are able to simulate regions that lack observation data, whilst applying a uniform approach for parameter estimation (Döll, Kaspar, and Lehner 2003; Widén‐Nilsson et al. 2009). Up until recently the GHMs used coarse modelling grids of around 0.5 to 1 degree spatial resolution. However, due to advances in satellite data, climate data, and computational resources, GHMs are modelling on higher resolutions (up to 200 meters) that raise questions about how these models can be adjusted in order to take advantage of the finer modelling grid.

In this study, we carry out an extensive assessment of how changes in spatial resolution affect the simulations of the Wflow SBM model for 8 basins in the Continental United States. This is done by comparing the model states and fluxes at three spatial resolutions, namely 3 km, 1km, and 200m. A hypothesis driven approach is used to investigate why changes in states and fluxes are taking place at different spatial resolutions and how they relate to model performance. The latter is determined by validating river discharge, snow extent, soil moisture, and actual evaporation. In addition, we make use of two sets of parameters that rely on different pedo-transfer functions. Further investigating the role parameterization in conjunction with changes in spatial resolution.

By carrying out this study within the eWaterCycle II framework we showcase our ability to handle large datasets (forcing and validation) whilst always complying to the FAIR principles. Furthermore, this study is setup in such that it is scalable in terms of case study areas and hydrological models.
Development of a microwave-based precipitation climate data record for the Copernicus Climate Change Service
Authors: Panegrossi Giulia , Sanò Paolo , Bagaglini Leonardo , Casella Daniele , Cattani Elsa , Konrad Hannes , Niedorf Anja , Schröder Marc , Mikalsen Anna Christina , Hollmann Rainer
Published: March 2020

Within the Copernicus Climate Change Service (C3S), the Climate Data Store (CDS) built by ECMWF will provide open and free access to global and regional products of Essential Climate Variables (ECV) based on satellite observations spanning several decades, amongst other things. Given its significance in the Earth system and particularly for human life, the ECV precipitation will be of major interest for users of the CDS.

C3S strives to include as many established, high-quality data sets as possible in the CDS. However, it also intends to offer new products dedicated for first-hand publication in the CDS. One of these products is a climate data record based on merging satellite observations of daily and monthly precipitation by both passive microwave (MW) sounders (AMSU-B/MHS) and imagers (SSMI/SSMIS) on a 1°x1° spatial grid in order to improve spatiotemporal satellite coverage of the globe.

The MW sounder observations will be obtained using, as input data, the FIDUCEO Fundamental Climate data Record (FCDR) for AMSU-B/MHS in a new global algorithm developed specifically for the project based on the Passive microwave Neural network Precipitation Retrieval approach (PNPR; Sanò et al., 2015), adapted for climate applications (PNPR-CLIM). The algorithm consists of two Artificial Neural Network-based modules, one for precipitation detection, and one for precipitation rate estimate, trained on a global observational database built from Global Precipitation Measurement-Core Observatory (GPM-CO) measurements. The MW imager observations by SSM/I and SSMIS will be adopted from the Hamburg Ocean Atmosphere Fluxes and Parameters from Satellite data (HOAPS; Andersson et al., 2017), based on the CM SAF SSM/I and SSMIS FCDR (Fennig et al., 2017). The Level 2 precipitation rate estimates from MW sounders and imagers are combined through a newly developed merging module to obtain Level 3 daily and monthly precipitation and generate the 18-year precipitation CDR (2000-2017).

Here, we present the status of the Level 2 product’s development. We carry out a Level-2 comparison and present first results of the merged Level-3 precipitation fields. Based on this, we assess the product’s expected plausibility, coverage, and the added value of merging the MW sounder and imager observations.

References

Anderssonet al., 2017, DOI:10.5676/EUM_SAF_CM/HOAPS/V002

Fennig, et al., 2017, DOI:10.5676/EUM_SAF_CM/FCDR_MWI/V003

Sanò, P., et al., 2015, DOI: 10.5194/amt-8-837-2015
The SIMIT-THARSY project: Upgrading the real-time monitoring system and risk assessment for earthquakes and tsunami on the Maltese islands
Authors: D'Amico Sebastiano , Agius Matthew , Farrugia Daniela , Galea Pauline
Published: March 2020

Within the SIMIT-THARSY project, the Maltese islands are upgrading their infrastructure for real-time earthquake and tsunami monitoring. The addition, through the project, of further broadband seismic stations to the Malta Seismic Network (MSN), managed by the Seismic Monitoring and Research Group (SMRG) of the University of Malta, has greatly improved the coverage for earthquake observations. The MSN now consists of eight broadband stations which will all feature online transmission, while a further three stations are planned. This upgrading means that smaller magnitude earthquakes occurring in all areas around the Maltese islands can be better detected and located. Such seismicity and microseismicity, although not generally presenting a threat to the islands, is helping to understand the nature and configuration of active faults on- and offshore the Maltese islands, which could potentially generate larger- magnitude events. Real-time earthquake monitoring, archiving and routine processing is carried out through SeisComP3 software, which is also used to create a virtual Mediterranean network for the monitoring of seismic activity in the Mediterranean basin and beyond. Also through the SIMIT-THARSY project, the SMRG has installed the tsunami monitoring package TOAST ((Tsunami Observation And Simulation Terminal) which integrates with SeisComP3 to detect tsunamigenic earthquakes, rapidly generate wave propagation simulations and predict arrival times and wave parameters at a pre-determined set of points of interest. This system, which is now operative, will contribute information to an eventual tsunami alert and preparedness programme that will be adopted by the national Civil Protection Department. A sea-level monitoring gauge will also be installed in the study area of Marsaxlokk Bay, southeast of Malta, which will contribute to the IOC online sea-level network that is integrated into the TOAST software for tsunami verification and modelling purposes.

Within the SIMIT-THARSY programme we are also implementing a seismic and tsunami-vulnerability index survey of buildings in the study area, together with geophysical investigations, which will be used to elaborate earthquake shaking and tsunami scenarios and form part of a Web-GIS database for preparedness and emergency management. In particular, single-station ambient noise measurements and seismic array analysis have been carried out in the test sites and earthquake scenarios will be computed combining both low and high frequency simulation methods. The results will be used to integrate the decision system mechanism in support of emergency planning.

SIMIT-THARSY is funded by the INTERREG V-A Italia-Malta Operational Programme (2014 – 2020)). The project partners are the Civil Protection Departments of Sicily and Malta and the Universities of Palermo, Catania and Malta.
An Environmental Explanation for the Recent Increase in Tropical Cyclone Intensification
Authors: Bhatia Kieran , Baker Alex , Vecchi Gabriel , Murakami Hiroyuki , Kossin James , Vidale Pier Luigi , Hodges Kevin , Knutson Thomas
Published: March 2020

Tropical cyclone (TC) rapid intensification events are responsible for intensity forecasts with the highest errors, and hurricanes that rapidly intensify cause a disproportionate amount of the fatalities and damage from TCs. According to a recent study by Bhatia et al. (2019), natural variability cannot account for the recent (1982-2009), observed increase in the highest TC intensification rates in the Atlantic Basin. These results agree well with the main conclusions of Bhatia et al. (2018), which demonstrated climate change could significantly increase TC intensification rates worldwide by the end of 21st century.

Expanding on the work of Bhatia et al. (2018, 2019), TC intensification trends are analyzed for the period 1982-2017 using two observational datasets, the International Best-Track Archive for Climate Stewardship (IBTrACS) and the Advanced Dvorak Technique-HurricaneSatellite-B1 (ADT-HURSAT). The extended observational datasets confirm significant upward trends in intensifications metrics. To explore a physical explanation for the climate change response of TC intensification, we use ERA5 reanalysis data to calculate trends in the favorability of storm environments. When evaluating environmental data, we use 6-hour increments at specific annuli around already-formed storms in order to focus on synoptic conditions unique to storm evolution and not genesis. The robust trends in a 36-year times series and corresponding evolution of storm environments corroborates a climate change fingerprint on TC intensification.
Landscape reconstruction and the relationship between human and environment in Yaowuyao area, Northeastern Tibetan Plateau since 15000 yr BP
Authors: Zhang Naimeng , Xu Qinghai , Zhang Dongju , Herzschuh Ulrike , Shen Zhongwei , Peng Wei , Liu Sisi , Chen Fahu
Published: March 2020

Understanding the paleoenvironment (such as climate and landscape) in the area where the early ancient human appears on the Tibetan Plateau is an interesting topic. Based on the results of pollen data on the Yaowuyao loess section of the Qinghai Lake Basin, we used landscape reconstruction algorithms to reconstruct the changes in vegetation cover for 15,000 years. It is shown that the vegetation in the Yaowuyao area changed from temperate steppe (15-7.5 ka) to forest-steppe (7.5-4 ka). Compared with previous studies on the sediment in Qinghai Lake, our study can better reflect the local environment of the Qinghai Lake basin. Furthermore, based on the paleoclimate change data and archeological data from the surrounding areas, it is noticed that while precipitation increases and trees increase, human activities decrease. This may be caused by the substance and strategies of the ancient human beings that have adapted to the steppe. In addition, our results also show that the intensity of ancient human activity has a negative correlation with plant biodiversity, which may be related to human disturbance to the environment. Our paleoecological and environmental study not only shows the paleoenvironment of the early human activities on the Qinghai-Tibet Plateau but also revealed possible early human activity signals.
Extratropical cyclone induced sea surface temperature anomalies in the 2013/14 winter
Authors: Dacre Helen , Josey Simon , Grant Alan
Published: March 2020

The 2013/14 winter averaged sea surface temperature (SST) was anomalously cool in the mid-North Atlantic region.  This season was also unusually stormy with extratropical cyclones passing over the mid-North Atlantic every 3 days.  However, the processes by which cyclones contribute towards seasonal SST anomalies are not fully quantified. In this paper a cyclone identification and tracking method is combined with ECMWF atmosphere and ocean reanalysis fields to calculate cyclone-relative net surface heat flux anomalies and resulting SST changes.  Anomalously large negative heat flux is located behind the cyclones cold front resulting in anomalous cooling up to 0.2K/day when the cyclones are at maximum intensity.  This extratropical cyclone induced 'cold wake' extends along the cyclones cold front but is small compared to climatological variability in the SST's.  To investigate the potential cumulative effect of the passage of multiple cyclone induced SST cooling in the same location we calculate Earth-relative net surface heat flux anomalies and resulting SST changes for the 2013/2014 winter period.  Anomalously large winter averaged negative heat flux occurs in a zonally orientated band extending across the North Atlantic between 40-60 oN. The 2013/2014 winter SST cooling anomaly associated with air-sea interactions (anomalous heat flux, mixed layer depth and entrainment at the base of the ocean mixed layer) is estimated to be -0.67 K in the mid-North Atlantic (68% of the total cooling anomaly).  The role of cyclones is estimated using a cyclone masking technique which encompasses each cyclone centre and its trailing cold front. The environmental flow anomaly in 2013/2014 sets the overall tripole pattern of heat flux anomalies over the North Atlantic.  However, the presence of cyclones doubles the magnitude of the negative heat flux anomaly in the mid-North Atlantic.  Similarly, the environmental flow anomaly determines the location of the SST cooling anomaly but the presence of cyclones enhances the SST cooling anomaly.  Thus air-sea interactions play a major part in determining the extreme 2013/2014 winter season SST cooling anomaly. The environmental flow anomaly determines where anomalous heat flux and associated SST changes occur and the presence of cyclones influences the magnitude of those anomalies.
Time-scale dependent relations of vegetation productivity with Earth Observation based proxies and with climate drivers
Authors: Linscheid Nora , Carvalhais Nuno , Mahecha Miguel , Rammig Anja , Reichstein Markus
Published: March 2020

New satellite products hold promise to improve our understanding of terrestrial ecosystem functioning, yet it remains a key challenge to measure global gross primary productivity (GPP) and its climate-induced fluctuations. While global estimates of GPP exist and several new satellite products hold potential for better GPP estimation, the best proxy of GPP may depend on the temporal and spatial scale considered, because available satellite products may differentially represent different time scales of vegetation dynamics. For example, vegetation indices such as NDVI and EVI may capture seasonal phenology well, while sun-induced fluorescence (SIF) may be more sensitive to short-term fluctuations of photosynthesis, and vegetation optical depth (VOD) may best represent slower changes in aboveground biomass. SIF in particular is proposed as a promising proxy for GPP as they show linear relationships with ecosystem-dependent slopes, but this may not be the case at all time scales.

In this study, we compare different Earth Observation vegetation proxies to FLUXCOM GPP in order to understand which vegetation proxy best represents GPP at sub-annual, annual and long-term scales with the aim to enable more accurate short- and long-term prediction of GPP and its drivers. We further assess the dominant climatic drivers of vegetation productivity and the vegetation’s sensitivity from sub-annual to inter-annual time scales using a multiple linear regression approach. We find the dominant drivers of vegetation productivity to differ across time scales in relation to land cover and climate.

In summary, depending on the time-scale, different satellite products best represent GPP and its climatic drivers. Considering this may help improve GPP estimates and predictions of long-term land carbon sink dynamics in the future.
Coupling geomorphology and hydrological modelling to characterize the spatio-temporal variability of groundwater-surface water interactions in karst rivers
Authors: Charlier Jean-Baptiste , Moussa Roger , Pinson Stéphanie , Narbaïs Didier , Desprats Jean-François
Published: March 2020

Flood hazard and groundwater resource management in karst catchments require a better understanding of the groundwater/surface water interactions. Due to their high infiltration capacity, karst outcrops limit runoff production on hillslopes, but promote in the same time lateral gains to rivers due to fast transfers underground. This topic is a great challenge, as 30% of Europe is cover by such karst areas.

The aim of this communication is to present recent developments on the characterization of karst-river interactions through two main approaches: a spatial approach aiming at localizing karst areas promoting surface flows, and a temporal approach aiming at modelling lateral flows from karst units in rivers.

The first spatial approach is based on the GIS index IDPR (Index of Development and Persistency of River networks, developed by BRGM©), quantifying the hydrological connectivity to the hydrographic network. From the standard version of the IDPR over France (25 m resolution), we have compare IDPR calculations differentiating intermittent and perennial reaches of rivers in order to detect infiltrations zones that contributive temporary to rivers, as many karst units. Results show that the presence of large karst units promote infiltration, but also temporary runoff that illustrate fast groundwater flows to rivers during floods.

The second approach is a modelling framework based on the inverse problem for the diffusive wave model, to simulate lateral flow during floods on a river reach between two stations. Knowing the upstream and downstream hydrographs, the lateral one is simulating, given informations on the hydrological processes involved in the intermediate catchment (losses, gains, or both processes during flood events). A new development has been tested, by adding continuous solute data (electrical conductivity) in order to track the origin of the water during floods. Applying such approach on river reaches crossing karst areas is a new way to quantify river losses, river gains from surface runoff or groundwaters, characterizing localized recharge and aquifer drainage to rivers, respectively.

We propose to illustrate these two approaches through several case studies in France, where a better characterization of groundwater-surface water interactions and flood risk management are critical issues.
Low-temperature thermochronology and vitrinite reflectance data reveal longwavelength uplift in the Alpine foreland basin
Authors: Louis Sarah , Luijendijk Elco , von Hagke Christoph , Dunkl István , Littke Ralf , Kley Jonas
Published: March 2020

Foreland basin sediments mirror the history of an orogeny. Deformation and geodynamic processes in low spatial extend (e.g. dozens of km) can be quantified using kinematic restoration. Processes happening deep underneath an orogen show a large spatial manifestation that is difficult to quantify in time and space. Marine units at surface outcrops show 900 m of net uplift since deposition in undeformed parts of the alpine foreland basin. Existing low-temperature thermochronology data from the Swiss part of the Molasse Basin show a thermal overprint that indicates exhumation of more than 1.5 km. We quantify the wavelength of deep seated processes of the Alpine orogen by generating and analyzing a holistic dataset of the entire alpine foreland basin. In addition to compiling existing data from the western part of the basin we have generated a new apatite (U-Th)/He and vitrinite reflectance data set from the central and eastern part of the basin. The new apatite (U-Th)/He ages in the German part of the basin show exhumation below or close to the detection limit (~1.5 km). Within the folded and thrusted Molasse, exhumation is localized along thrusts and the thermochronological data indicates thrusting between 10 to 20 Ma. Vitrinite reflectance data reveals a trend of exhumation increasing from East to West. Parts of the central German Molasse basin have been exhumed as well. Thus, on the large scale we can see longwave exhumation patterns in the western part of the basin that affect both the deformed and undeformed parts of the basin which cannot only be related to Jura thrusting.
Whole system Approach for In-situ & Long-term environmental System research on life supporting systems (WAILS)
Authors: Mirtl Michael
Published: March 2020

Environmental research is challenged by the question, how lilfe supporting systems (ecosystems, the critical zone) and their services will develop in the next decades. However, addressing changes in structure and function requires an integrated approach from the subsurface to the vegetation and atmosphere, across scales and ecosystems, and combining observation, ecosystem theories and modelling. Such integrated approach affects most aspects of how environmental research and monitoring are shaped, comprising seamless collaborations amongst involved disciplines, the interactions of actual research with other stakeholders, research insfrastructure design and operation and – as a key factor – the structures and rulesets of related funding mechanisms.

A common conceptual framework is highly relevant for catalyzing integration efforts and implementing complementary modules of research infrastructures serving various user groups and disciplines towards a fundamental understanding and improved predictions of how structure and functions of ecosystems and ecosystem services will evolve and adapt under global change, with climate change, land use and societal change as key drivers.

Triggered by the challenge to streamline the ecoystem, critical zone and socio-ecological reasearch infrastructure at the Pan-European level in close collaboration with other ongoing European environmental RIs like ICOS and LifeWatch, the eLTER Research Infrastructure (RI) therefore strives for a Whole system Approach for In-situ & Long-term environmental System research on life supporting systems (WAILS), combining humans-environment interactions at a given scale and cross-scale interactions and feed-back loops across scales, which will be presented.
Stochastic hydrogeological parameterisation and modelling of the Chalk of England
Authors: Bianchi Marco , Hughes Andrew , Mansour Majdi , Scheidegger Johanna Michaela , Jackson Christopher
Published: March 2020

The Chalk is the most important regional aquifer in England supplying the majority of the groundwater used in the country. Traditionally, the Chalk has been interpreted as a dual-porosity aquifer consisting of a low-permeability, high-porosity matrix and a fracture component with associated relatively high secondary permeability, allowing groundwater flow. However, these two components alone cannot fully explain the groundwater flow regime and aquifer productivity indicating that the distribution of the hydrogeological properties is the result of more complex interplay of several regional and local factors. For instance, transmissivity generally exhibits a non-linear decline with depth controlled by variations in the spacing and aperture of the primary and secondary (solution) fractures. Topography is another important regional factor determining a spatial distribution of transmissivity (T) and storage coefficient (S) with generally higher values within valleys and lower values in the interfluves. The topographic factor is widely recognised, and it has been applied in several previous numerical modelling studies. However, these studies do not consider the local variability exhibited within an extensive dataset of more than 1000 pumping tests, while local adjustments of the initial topography-based T and S distributions are considered during the calibration step of the model. In this work, a hybrid geostatistical approach has been developed and applied for modelling the distribution of the hydrogeological properties of the Chalk. The approach combines, for the first time for the Chalk, local hard data from pumping tests with soft data accounting for the regional topographic trend. In particular, similar to the classic regression kriging approach, stochastic realisations of the T distribution in the unconfined region of the Chalk are generated from the combination of two components: 1) a non-linear deterministic model of the relationship between measured T values and the distance to valleys; 2) a sequential Gaussian simulation (SGS) component generating equally probable realizations of the residuals conditioned to the local data. Traditional conditional sequential Gaussian simulation was used instead to generate T and S spatial distributions in the confined region. To test the representativeness of the generated distributions, realisations of the hydrogeological parameters were considered for groundwater flow simulations based on a transient 2-D finite difference model coupled to a regional recharge model. Comparison between observed and simulated values for groundwater levels and river flows at reference locations showed a generally good agreement. The model was then used to quantify the importance of local hydrogeological data for improving model predictions versus alternative conceptualisations solely based on regional trends and model calibration.
Assessing sensitivity and persistence of updated initial conditions through Particle filter and EnKF for streamflow forecasting
Authors: Piazzi Gaia , Thirel Guillaume , Perrin Charles
Published: March 2020

Skillful streamflow forecasts provide a key support to several water-related applications. Ensemble forecasting systems are gaining a widespread interest, since they allow accounting for different sources of uncertainty. Because of the critical impact of the initial conditions (ICs) on the forecast accuracy, it is essential to improve their estimates via data assimilation (DA). This study aims at assessing the sensitivity of the DA-based estimation of forecast ICs to several sources of uncertainty and to the update of different model states and parameters of a conceptual rainfall-runoff model. The performance of two sequential ensemble-based techniques are compared, namely Ensemble Kalman filter and Particle filter, in terms of both efficiency and temporal persistence of the updating effect through the assimilation of observed discharges at the forecast time. Several experiments specifically address the impact of the meteorological, model state and parameter uncertainties over 232 catchments in France. Results show that the benefit of the DA-based estimation of ICs for forecasting is the largest when focusing on the level of the model routing store, which is the internal state the most correlated to streamflow. While the EnKF-based forecasts outperform the PF-based ones when accounting for the meteorological uncertainty, the representation of the model state uncertainty allows greatly improving the accuracy of the PF-based predictions, with a longer-lasting updating effect (up to 10 days). Conversely, the forecasting skill is undermined when accounting for the parameter uncertainty, due to the change in the hydrological responsiveness through the update of both the production and routing store levels. A further effort is focused on assessing the impact of the spatial resolution of the hydrological model on the predictive accuracy of DA-based streamflow forecasts.
Extensive, Gas-charged Quaternary Sand Accumulations of the Northern North Sea and North Sea Fan
Authors: Bellwald Benjamin , Planke Sverre , Vadakkepuliyambatta Sunil , Buenz Stefan , Batchelor Christine , Manton Ben , Zastrozhnov Dmitry , Myklebust Reidun , Kjølhamar Bent
Published: March 2020

Sediments deposited by marine-based ice sheets are dominantly fine-grained glacial muds, which are commonly known for their sealing properties for migrating fluids. However, the Peon and Aviat hydrocarbon discoveries in the North Sea show that coarse-grained glacial sands can occur over large areas in formerly glaciated continental shelves. In this study, we use conventional and high-resolution 2D and 3D seismic data combined with well information to present new models for large-scale fluid accumulations within the shallow subsurface of the Norwegian Continental Shelf. The data include 48,000 km2 of high-quality 3D seismic data and 150 km2 of high-resolution P-Cable 3D seismic data, with a vertical resolution of 2 m and a horizontal resolution of 6 to 10 m in these data sets. We conducted horizon picking, gridding and attribute extractions as well as seismic geomorphological interpretation, and integrated the results obtained from the seismic interpretation with existing well data.

The thicknesses of the Quaternary deposits vary from hundreds of meters of subglacial till in the Northern North Sea to several kilometers of glacigenic sediments in the North Sea Fan. Gas-charged, sandy accumulations are characterized by phase-reserved reflections with anomalously high amplitudes in the seismic data as well as density and velocity decreases in the well data. Extensive (>10 km2) Quaternary sand accumulations within this package include (i) glacial sands in an ice-marginal outwash fan, sealed by stiff glacial tills deposited by repeated glaciations (the Peon discovery in the Northern North Sea), (ii) sandy channel-levee systems sealed by fine-grained mud within sequences of glacigenic debris flows, formed during shelf-edge glaciations, (iii) fine-grained glacimarine sands of contouritic origin sealed by gas hydrates, and (iv) remobilized oozes above large evacuation craters and sealed by megaslides and glacial muds. The development of the Fennoscandian Ice Sheet resulted in a rich variety of depositional environments with frequently changing types and patterns of glacial sedimentation. Extensive new 3D seismic data sets are crucial to correctly interpret glacial processes and to analyze the grain sizes of the related deposits. Furthermore, these data sets allow the identification of localized extensive fluid accumulations within the Quaternary succession and distinguish stratigraphic levels favorable for fluid accumulations from layers acting as fluid barriers.
Multi-temporal mass balance changes of the Northern Patagonian Icefield from 1975 to 2016
Authors: Berthier Etienne , Dussaillant Ines , Brun Fanny , Favier Vincent
Published: March 2020

The northern Patagonian Icefield (NPI) is the second largest ice mass in Patagonia (3740 km²). Estimation of recent volume changes confirm an acceleration of ice loss in the last decades compared to the mean mass loss since the Little Ice Age. However, Icefield-wide responses at shorter time scales (5-25 yrs) are still poorly documented and not well understood.

We compare five digital elevation models (DEM) acquired between 1975 and 2016 over the NPI: SPOT6 and SPOT7 DEMs for year 2016, SPOT5-HRS DEMs for 2012 and 2005, the Shuttle Radar Topography Mission DEM (SRTM) for year 2000 and the earlier Chilean military institute cartography (IGM) derived from aerial photographs acquired in 1975. We derive cefield-wide mass balances during four different time periods (1975-2000, 2000-2005, 2005-2012, 2012-2016). Our results suggest an acceleration of mass loss from 1975 to 2016. Although error bars are large, we suggest a shift from moderately negative icefield-wide mass balance rates before 2000 (of the order of -0.6 m w.e. yr-1), towards larger mass losses during the first decade of the 21st century(of the order of -0.8 m w.e. yr-1) and even more negative value from 2012 to 2016 (-1.2 ± 0.2 m w.e. yr-1).

But these results must be considered cautiously. The 1975-2000 map of elevation change shows a thickening rate of over 1 m/yr which are not supported by image analysis. We stress the need to construct a revised 1975 NPI topography in order to document the NPI mass balance observations back to 1975 with improved confidence.
From Fear to Hope: The inspiring journey of an 11-year-old Environmental Activist
Authors: Halstead Florence , Parsons Lucie , Parsons Katie
Published: March 2020

"When I first became aware of the destruction of the world through climate change, I felt very upset and angry, but also a little worried.  What was going to happen to my world? And what was everyone going to do about it, including me?” (Parsons, 2019).

The Earth is currently undergoing a sixth global scale ecological crisis. The available science almost unanimously positions human activity at the heart of the cause of this crisis, with anthropogenic emissions of greenhouse gasses, pollution, land degradation and deforestation, all contributing. Recent IPCC reporting has demonstrated a need to curb global warming at 1.5 degrees above the pre-industrial baseline and have highlighted a range of likely impacts of Climate Change should no action be taken, particularly in relation to reducing greenhouse gas emissions to net zero by 2050. Despite this need, policy-based action at a nation state level is largely lacking, with recent talks at COP25 failing to reach agreements. However, a significant global youth movement is now underway, with children and young people taking it upon themselves to highlight a need for climate and environmental action, calling for others to follow. Greta Thunberg and the Fridays For Future (#FFF) movement now regularly appears in mainstream media, highlighting the issues of Climate Change with an emotive narrative centred on the impact of future climate change on today’s children and their environments.

Whist there is growing literature that explores Youth Activism, to our knowledge, there is no investigation that has followed the emotional journey of a child whom has chosen to take environmental action. Here, we present Lucie Parsons, an 11-year old girl who, after watching BBC’s Blue Planet II back in 2017 and seeing the devastation plastic pollution was having on the marine environment and its wildlife, decided to take action and be a champion for positive environmental change. Since then, Lucie has spoken at international conferences, conducted her own research in her primary school, organised regional litter picks, and has become an Ambassador for the national charities iWill and Kids Against Plastic; amongst many other things. As her activism has gained momentum and as she has become more aware of wider environmental issues, her focus on plastic pollution has broadened to include the current climate crisis and environmental degradation as a whole. We will present the highs and lows of Lucie’s Environmental Activism and the role that emotion has played in her journey thus far; as well as what she believes to be the achievements in her own science communication and what you as scientists can do to help her in her fight against environmental and climatic change.

 