bluuebunny/crossref_metadata_2025 huggingface dataset:
Upscaling of elastic properties in carbonates: A modeling approach based on a multiscale geophysical data set
Authors: Fortin Jerome , Bailly Cedric , Adelinet Mathilde , Hamon Youri
Published: March 2020

Linking ultrasonic measurements made on samples, with sonic logs and seismic subsurface data, is a key challenge for the understanding of carbonate reservoirs. To deal with this problem, we investigate the elastic properties of dry lacustrine carbonates. At one study site, we perform a seismic refraction survey (100 Hz), as well as sonic (54 kHz) and ultrasonic (250 kHz) measurements directly on outcrop and ultrasonic measurements on samples (500 kHz). By comparing the median of each data set, we show that the P wave velocity decreases from laboratory to seismic scale. Nevertheless, the median of the sonic measurements acquired on outcrop surfaces seems to fit with the seismic data, meaning that sonic acquisition may be representative of seismic scale. To explain the variations due to upscaling, we relate the concept of representative elementary volume with the wavelength of each scale of study. Indeed, with upscaling, the wavelength varies from millimetric to pluri-metric. This change of scale allows us to conclude that the behavior of P wave velocity is due to different geological features (matrix porosity, cracks, and fractures) related to the different wavelengths used. Based on effective medium theory, we quantify the pore aspect ratio at sample scale and the crack/fracture density at outcrop and seismic scales using a multiscale representative elementary volume concept. Results show that the matrix porosity that controls the ultrasonic P wave velocities is progressively lost with upscaling, implying that crack and fracture porosity impacts sonic and seismic P wave velocities, a result of paramount importance for seismic interpretation based on deterministic approaches.

Bailly, C., Fortin, J., Adelinet, M., & Hamon, Y. (2019). Upscaling of elastic properties in carbonates: A modeling approach based on a multiscale geophysical data set. Journal of Geophysical Research: Solid Earth, 124. https://doi.org/10.1029/2019JB018391
The LSA-SAF ET product: an operational service of sub-daily estimation of evapotranspiration in near-real time across Europe, Africa and Eastern South America
Authors: Barrios José Miguel , Arboleda Alirio , Gellens-Meulenberghs Françoise
Published: March 2020

The Satellite Application Facility on Analysis on Land Surface Analysis (LSA-SAF) has been set up by the European Organization of the Exploitation of Meteorological Satellite (EUMETSAT, see http://lsa-saf.eumetsat.int/). Its major goal is the development of products characterizing the condition of the Earth's continental surfaces on the basis of meteorological satellite observations.

The exchange of energy and water fluxes between the Earth's surface and the atmosphere is a major phenomenon driving a series of processes that impact human life. Noteworthy examples are: agriculture yields, local weather conditions, water availability, intensity and extent of droughts, the ability of ecosystems to provide services to society, etc. The relevance of these processes has motivated the exploitation of satellite observations from the Meteosat Second Generation (MSG) to develop algorithms for the estimation of evapotranspiration (ET) and both latent and sensible heat fluxes in an operational framework functioning in near-real time.

The LSA-SAF ET product comprises half-hourly and daily estimates across Europe, Africa and the east side of South America. The quality of the ET product has been assessed by contrasting the estimates to in-situ measurements in flux measurement stations scattered across diverse climatic regions and plant cover types. The validation exercises -conducted by the development team as well as by independent studies- have corroborated the good quality of the product.

This contribution is intended to share details of the main principles of the algorithm (with insight to latest developments), the forcing variables (including several products derived from the SEVIRI instrument on-board MSG) and the ways of accessing and using the data.
The impact of ENSO and the Atlantic Multidecadal Variability (AMV) on the upper tropospheric large scale flow in the PRIMAVERA models.
Authors: Ghinassi Paolo , Fabiano Federico , Meccia Virna L. , Corti Susanna
Published: March 2020

Rossby waves play a fundamental role for both climate and weather. They are in fact associated with heat, momentum and moisture transport across large distances and with different types of weather at the surface. Assessing how they are represented in climate models is thus of primary importance to understand both predictability and the present and future climate. In this study we investigate how ENSO and the AMV affect the large scale flow pattern in the upper troposphere of the Northern Hemisphere, using reanalysis data and data from the PRIMAVERA simulations.

The upper tropospheric large scale flow is investigated in terms of the Rossby wave activity associated with persistent and recurrent patterns over the Pacific-North American and Euro-Atlantic regions during winter, the so called weather regimes. In order to quantify the vigour of Rossby wave activity associated with each weather regime we make use of a recently developed diagnostic based on Finite Amplitude Local Wave Activity in isentropic coordinates, partitioning the total wave activity into the stationary and transient components. The former is associated with quasi-stationary, planetary Rossby waves, whereas the latter is associated with synoptic scale Rossby wave packets. This allows one to quantify the contribution from stationary versus transient eddies in the total Rossby wave activity linked to each weather regime.

In this study we explore how ENSO and the AMV affect both the weather regimes frequencies and the upper tropospheric waviness in the Pacific and Atlantic storm tracks, respectively. Furthermore we analyse how both the stationary and transient wave activity component modulate the onset and transition between different regimes.
Investigating the sensitivity of direct, semi-direct and indirect effects of aerosols to changes in the emissions of individual aerosol species using a climate model.
Authors: Sharma Amit kumar , Ganguly Dilip
Published: March 2020

 Atmospheric aerosols emitted from both natural and anthropogenic sources play a crucial role in the Earth’s radiation budget and regulating its climate. The mechanisms through which aerosols influence the radiation budget of the Earth is often classified as direct, semi-direct, and indirect effects of aerosols. It is important to understand the perturbation caused in the radiation budget of the Earth due to changing emissions of individual aerosol species and their precursors not only for estimating the responses of the climate system to such perturbations but also to be able to attribute these responses to changes in specific aerosol species and their sources for planning any mitigation or adaptation strategy to any undesirable consequences of climate change caused by aerosols. In the present study we use the Community Atmosphere Model version 5.3 (CAM5.3) to quantify the direct, semi-direct, and indirect aerosol radiative forcing due to changes in the emissions of individual aerosol species or their precursors from the pre-industrial (PI) to present day (PD) period following a new methodology proposed by Ghan et al. (2012) involving additional radiative diagnostics with neglected absorption and scattering of aerosols, whereas absorption and scattering of aerosols for the actual model setup remains unchanged. A series of systematically designed simulations with concentrations of individual aerosol species set to zero are conducted in order to estimate the direct, semi-direct, and indirect aerosol radiative forcing due to the corresponding aerosol species. Our preliminary results shows the global annual mean value of direct Short-Wave radiative forcing (DRF) at TOA due to all aerosols to be around -0.01W/m2, while the Cloud radiative forcing (CRF) to be around -1.5W/m2. The bias in the aerosol radiative forcing estimates as per the old conventional method are almost -0.55W/m2 for DRF which is nearly 60 times the DRF estimated using the new approach and 0.23W/m2 for CRF which is almost 15.43% of the total CRF at TOA respectively. Interestingly, for the South Asian region, the DRF based on the new approach is found to be positve in almost across south Asia (0.097 W/m2) thereby signifying a trapping of energy in the atmosphere due to aerosols, whereas according to the old conventional method the DRF is estimated to be around -0.59 W/m2 signifying a loss of energy in the atmosphere due to aerosols. Similarly a difference of about 1 W/m2 is noted in the estimates of CRF as per the new and the old methods of estimating radiative forcing. More results with greater details on the contribution of individual aerosols towards the total aerosol radiative forcing and other important meteorological parameters will be presented.
On the applicability of ICESat-2 and off-nadir SkySAT satellite datasets for the estimation of water storage in medium and small reservoirs at the global scale
Authors: Donchyts Gennadii , Eilander Dirk , Moreno-Rodenas Antonio , Pronk Maarten , Roy Samapriya , Winsemius Hessel
Published: March 2020

Accurate and timely information on water storage changes in medium and small size reservoirs is needed for better water management and understanding of water dynamics on a global scale in general. While changes in surface water extent in these reservoirs can be monitored using satellite missions such as Landsat 8, Sentinel-1, and Sentinel-2, the information on water level and storage dynamics on a global scale is still missing. However, for most reservoirs, these storage changes can be estimated given that an accurate digital elevation model (DEM) is available for a dynamic part of the reservoir - the area covered between the minimum and maximum extents of the reservoir. In this research, we will investigate the applicability of data measured by the ICESat-2 lidar sensor and the off-nadir satellite imagery acquired by Planet’s SkySAT satellites and will evaluate how valuable these datasets are to estimate water storage changes in medium and small size reservoirs.
High-precision dating of MIS 7 using Austrian Alp stalagmites
Authors: Wendt Kathleen , Li Xianglei , Cheng Hai , Edwards R. Lawrence , Spötl Christoph
Published: March 2020

We present a high-precision record of the Penultimate Interglacial (MIS 7) and the Penultimate Glacial inception (MIS 7–6 transition) from Spannagel Cave in the central European Alps (southern Austria). Drip waters in this high-elevation cave are largely sourced from the overlying low-permeability gneiss, giving rise to unusually high uranium concentrations in secondary calcite deposits (up to 200 ppm). The large quantities of 234U and 230Th incorporated in samples can be measured using high-precision spectrometry, resulting in relative age uncertainties as low as 1‰ (2σ) during our study period (~250 to 197 thousand years ago [ka]). Using this unprecedented age control, we revisit Spannagel stalagmite SPA121 that grew continuously throughout MIS 7 and the MIS 7–6 transition. Previous work by Spötl et al. (EPSL 2008) revealed that SPA 121 δ18O displays similar timing and structure to global benthic marine δ18O during MIS 7, including distinct sub-stages. New dating allows us to constrain the exact timing and duration of MIS 7 sub-stages in the European Alps, including the timing of Terminations (T) III and IIIa. Preliminary results show the onset of MIS 7e at 241.4 ± 0.3 ka, the δ18O minima during MIS 7b at 224.5 ± 0.3 ka, and the mid point of TIIIa at ~216.2 ± 0.3 ka. The onset of decreasing δ18O associated with the MIS 7a–6e transition occurred no later than 193.0 ± 0.2 ka. Two newly collected stalagmites from this cave (SPA146 & 183) provide two high-resolution replications of the MIS 7a–6e transition. The resulting multi-stalagmite record will provide important chronological constraints on climate shifts in the European Alps during the Penultimate Interglacial and subsequent glacial inception.
Characterization of historical inorganic binders and design of restorative materials - case study of the late Roman mosaic
Authors: Ranogajec Jonjaua , Vucetic Snezana , Frankovic Maja , Hirsenberger Helena
Published: March 2020

The design of restorative mortars for historical buildings and artefacts is always a challenging task, with multiple requirements which have to be achieved and harmonized. Essentially, restorative mortars have to comply with chemical, mineralogical and mechanical compatibility criteria, which also include formation of contact zone, tensile strength, porosity and visual properties (colorimetric parameters). One of the successfully restored examples is the mosaic discovered broken in 2014 with severely disturbed positioning of fragments. The mosaic represents head of Medusa dated from Late Roman period and found at the archaeological site in Skelani, Bosnia and Herzegovina.

 

The case study presented in this abstract is a good practice example of collaboration between restoration and science which shortens the period for attaining relevant inputs and gives confidence to future restoration decisions. The investigation reviled that the mosaic bedding layer was of very good quality and has allowed fragments of various sizes to be preserved (tesselatum, nucleus and even rudus layer on some fragments). The objective of the restoration was to preserve remains of the original bedding layer and to connect and stabilize groups of individual fragments. The idea was to design compatible restoration mortar which will support the requirements for future mosaic presentation.

 

The characterization of historic inorganic binder samples, performed in the Laboratory for Materials in Cultural Heritage, Faculty of Technology, University of Novi Sad, provided invaluable information about the composition of mosaic bedding layers, their preparation, and moreover about degradation mechanisms in regard to centuries of its use and environmental conditions. It was reviled that the original inorganic binder is a lime based mortar with brick fragments imbedded. A strong bonding with preserved bedding layers of mosaic fragments and a set of specific compatibility objectives framed attempts to design compatible restorative mortar. In the laboratory a set of restorative mortar samples were prepared with similar chemical and mineralogical composition, porosity and visual properties (colorimetric parameters), mechanical properties and formation of contact zone between original and restorative mortar. The laboratory prepared samples were artificially aged in weathering chamber (temperature, humidity, UV/VIS radiation) simulating exposal to real environmental conditions in all four seasons. The weathering regimes were set according to temperature and humidity profiles for the relevant region. Finally, the compatibility of restoration mortar with original one was evaluated and confirmed, what enabled conservators to proceed with restorative works.
Comparing different types of solar flares with radio bursts detected by SMOS
Authors: Flores Soriano Manuel , Cid Consuelo
Published: March 2020

SMOS is an Earth observing satellite that is been adapted to provide full polarization observations of the Sun at 1.4 GHz 24 hours a day. Its solar radio observations from the last decade will be released to the community by the middle of this year. In this presentation we show the capabilities of SMOS as a solar radio observatory and compare some of the most relevant radio bursts with data from GOES, LASCO, SDO and RSTN. We show how SMOS responds to different kinds of solar flares depending on their x-ray flux, and the kind of mass ejection or solar dimming that they have produced, if any. In addition to this we also show the potential of SMOS as a space weather tool to monitor GNSS satellites signal fades and to provide an early warning of Earth-directed coronal mass ejections.
Tracer Design and Gas Monitoring of a CO2 Injection Experiment at the ECCSEL CO2 Field Lab, Svelvik, Norway
Authors: Wolfgang Weber Ulrich , Heeschen Katja , Zimmer Martin , Raphaug Martin , Hagby Klaus , Ringstad Cathrine , Sundal Anja
Published: March 2020

The ECCSEL Svelvik CO2 Field Lab outside Oslo has been set up for water and CO2 injection experiments. At the site, ongoing and future investigations on monitoring techniques for carbon capture and storage (CCS) shall support the development of CCS as a climate change mitigation technology in Norway.

In 2019, four 100 m deep injection wells with a sophisticated physical monitoring setup were established. For chemical monitoring a fluid sampling system at injection depth was installed and coupled to a continuously measuring mass spectrometer for observing CO2 distribution. Alongside, a network of soil gas flux chambers (LI-COR 8100) were set up to monitor possible surface leakages.

The field lab is placed in a sand quarry within the Svelvik Ridge consisting of Holocene, siliciclastic sediments. Injection is conducted into a saltwater aquifer at 65m, supposedly sealed by clay strata. We sampled the upper fresh water aquifer at 6.5m depth and the storage aquifer at 64 - 65 m depth on dissolved gases before injection in order to design a noble gas tracer for the CO2 injection experiment. Elevated helium concentrations in the saline aquifer indicate natural radiogenic accumulation; meanwhile krypton concentrations were not naturally increased.

During an injection experiment in fall 2019, we added noble gases, i.e. krypton and helium, in two subsequent injection cycles, three days and one week, respectively. Outgassing was observed and high helium concentrations verified a leakage at the injection well, which we quantified with a flux chamber.
Landfill characterization by multi-method geophysical investigation: the case study of Leppe (Germany)
Authors: Debouny Tom , Caterina David , Isunza Manrique Itzel , Beese-Vasbender Pascal , Nguyen Frédéric
Published: March 2020

Whether environmental or economic interests are at stake, characterization of landfills is becoming a key operation. Characterization not only concerns old landfills, but also modern engineered landfills where the assessment and monitoring of internal processes such as leachate and biogas generation is of a primary importance. Nowadays, characterization is mostly carried out by conventional invasive methods based on drilling/trenching, sampling and laboratory analyses. Although they provide direct and analytical information, their spatial coverage, or representability, remains a major drawback. In addition, they can be expensive and increase the risk of damaging contamination barriers. Therefore, non- to minimally- invasive characterization geophysical techniques emerge as a complementary option. They allow to better capture the spatial heterogeneity across a site and are more cost-effective than punctual measurements alone. Furthermore, when compared with limited ground truth data, they may provide insights into waste composition, water content or temperature. The present study highlights the added value of a multiple geophysical approach to characterize a landfill located in Engelskirchen in Germany. Leppe landfill was used as a municipal solid waste (MSW) deposit site from 1982 until the end of 2004. Since then, only ash coming from the MSW incineration is discarded, mostly on top of the previous MSW deposit. The combination of geophysical methods used in this study included electrical resistivity tomography (ERT),  induced polarization (IP), multichannel analysis of surface waves (MASW) and horizontal to vertical noise spectral ratio (HVSNR). The 3D ERT and IP model allowed to identify dry zones within the waste (which may have a direct impact on biogas production) and to roughly discriminate the layer of ash from the MSW layer. Seismic velocity model provided by MASW permitted to significantly improve the delineation between the two layers. HVNSR results combined with the information provided by MASW were used to estimate the thickness of the top layer on a larger area using a bilayer hypothesis. These geophysical characterization results were validated with available ground truth data. Overall, in the present case seismic methods showed to be more suited than geoelectrical techniques for the distinction between the ash and MSW layers.
Realtime geomagnetic indices for mid-latitudes. MID-R, MID-E, MID-U and MID-L
Authors: Guerrero Antonio , Saiz Elena , Cid Consuelo
Published: March 2020

Mid latitudes around 40 degree are influenced by effects typically found at both high and low latitudes. Moreover, the focus of the Solar Quiet ionospheric current system, drifts around these mid-latitudes. Consequently they have been considered as a complicated place to infer the geospace state from the ground and also complicated for practical procedures to generate geomagnetic indices. 
The procedure designed at the University of Alcala specially focused on removing solar regular variations at mid-latitudes is delivering a geomagnetic Local Disturbance index (LDi) in realtime. The same procedure can be used to produce global geomagnetic indices when applied to several geomagnetic stations at these latitudes. 
We present in this work the high-resolution (one minute) realtime production of ring current and auroral indices (MID-R, MID-E, MID-U and MID-L) similar to the well known Dst and AE indices for mid-latitudes which will help in the understanding of the complex physical processes that emerge at these latitudes. At the same time they fill a gap in the current operational space weather products available for these latitudes.
Metal and phosphorus in bottom sediment of a small-sized reservoir in a rural mountainous catchment (NE Portugal): accumulation and geochemical mobility
Authors: Reis Anabela , Roboredo Marta
Published: March 2020

Small-sized reservoirs have less capacity for the retention of sediment but are widely distributed in regulated basins. Therefore, small reservoirs collectively impart an important anthropogenic signature to the global sediment-flux, increasing the mean sediment retention when compared with estimates of mean sediment retention of large reservoirs.

A geochemical study of sediment-associated metal and phosphorus from a small-sized riverine reservoir, located in a mountainous rural region (Vila Real in NE Portugal), was conducted to evaluate the effectiveness of the reservoir as traps for these elements. The contents of metals and P were determined, as well as their spatial distribution pattern and their potential availability by using a four-step sequential extraction procedure for metals and the Chang and Jackson fractionation for P.

The metal contents in sediments were in the ranges of (µg/g): Cr (22-122); Cu (31-83); Ni (5-71); Pb (49-160); Zn (207-334). All the geochemical phases studied were important in the retention of the metals; within the most labile fractions, the reducible fraction was the most significant. The studied elements can be classed by potential relative mobility: Zn > Pb > Cu > Cr, Ni. The partition of elements contents through the geochemical phases and the balance between contents associated with the most mobile fractions and with the residual fraction suggest an important contribution from lithology to the total contents of Cr and Ni, and a significant contribution of anthropogenic activities to the contents of Cu, Pb, and Zn in the sediments from the reservoir. The analysis of the results on the geochemical partitioning of metals revealed to be important when the Sediment Quality Guidelines (SQGs) are considered. Phosphorus showed contents ranging between 1518-2454 µg/g; most samples revealed the predominance of the Fe-P fraction.

In general, the sediments of the reservoir showed maximum values of contents of metals above the Threshold Effect Level (TEL, µg/g: Cr-37.3; Cu-35.7; Ni-18; Pb-35; Zn-123). Chromium, Ni, Pb and Zn showed total contents exceeding the values of Probable Effect Level (PEL, µg/g: Cr-90; Cu-197; Ni-36; Pb-91.3; Zn-315). Chromium and Ni showed higher values than the reference ones, but these can be considered relatively unavailable since they are associated with the residual phase. The potentially available and/or total amounts of metals and P in sediments were relatively high, indicating that the quality of bottom sediments accumulated in this small-sized reservoir should be considered in management policies.
Establishment of a Procedure for Blast Mining During Construction of New Highway in the Vicinity of Treska River Spring
Authors: Dojcinovski Dragi , Gjogjiev Igor , Panovska Frosina , Panovski Aleksandar , Mitev Blazho , Gjorgjeska Irena , Stojmanovska Marta
Published: March 2020

The waters of Treska river come from a fractured and karstified aquifer. A new highway route running over the aquifer has been designed for this area. Unfortunately, the construction of the new highway demands a series of mining blasts for the purpose of laying out the route.  Therefore, it was necessary to investigate whether the blasts could damage the aquifer and affect the water flow or its quality. To that effect, the capacity (flow) and the quality (purity, clarity of water, possible muddiness during and after trial mining) of water were monitored. A procedure had to be established for the purpose of investigating the influence of the blast waves on the rock medium in which the aquifer is embedded. The geological structure of the terrain along the route is represented by Triassic dolomite limestone that is cracked on the surface and karstified. Since our country doesn’t have any standards that cover the field of blasts and explosions, the Swiss standard (SWISS 640312:2013) was used.The main objective was  to evaluate the effects of blasting works on a cut in the zone of the Treska river spring, along the new highway route, namely subsection 2 of Kichevo – Ohrid motorway, in respect to the geological and hydrological characteristics of the terrain of the Treska river spring, define a methodology for performance of trial blasting, evaluate the effect of trial blasting, draw conclusions and provide  recommendations of measures and further activities.

Three trial blasts were performed on three trial fields according to the “far to close” principle and using  low destruction blasting technology with continuous monitoring of the velocity of blast waves as well as monitoring of the quantity and quality of the water (possible muddying) flowing from the spring.

The trial blasts were performed in sequences, on blasting fields with a radius of effect of 50 m and using quantities of explosives causing vibrations that are lower than the allowed ground vibration limit. According to the results obtained from the trial blasts, it can be concluded that the trial blasts in the vicinity of Treska river spring performed under good control and high quality monitoring of the blasting process will not have negative effect upon the spring flow regime. Also, the results obtained from the conducted geophysical surveys do not point to important changes of the physical-mechanical characteristics of the terrain structure after the trial blasts. In these zones, local disturbances as those during the referent measurements were defined. It is recommended to follow the same procedure for mining the rock medium during the construction works.
Long-term Trend of Planetary Boundary Layer Height in Climate Models and Observations over East Asia
Authors: Yue Man , Wang Minghuai
Published: March 2020

Abstract: Planetary boundary layer (PBL) plays an important role in climate and air quality simulations. Large uncertainties remain in understanding the long-term trend of PBL height (PBLH). In this study, radiosonde data and ERA-Interim reanalysis data are applied to reveal the critical climate factors and mechanisms dominating the long-term trend of PBLH over East Asia. Our results show that, observed long-term shift in PBLH trend is found to be consistent with changes in sensible heat flux (SHFLX), net downward surface shortwave flux (SWFLX) and low cloud cover (LCC). Increases in soil moisture and LCC in recent years can modulate the energy partition through the SHFLX and modifying the surface radiation budget, and further lead to the long-term shift trend of PBLH. Long-term trend of PBLH over East Asia is further examined in climate models (including NCAR CESM2) and data from the Coupled Model Inter-comparison Project Phase 6 (CMIP6) experiments. The global climate models are not able to reproduce the long-term trend of PBLH over East Asia. CESM2 is shown to not catch the long-term variability of sensible heat flux and surface shortwave flux. Further analysis is performed to examine how the trend of mean PBLH and extreme low PBLH may be different.
Application of precision technologies in geomorphology: analysis of the flash flood occurred in Sant Llorenç des Cardassar, Mallorca, October 2018
Authors: Estrany Bertos Joan , Ruíz-Pérez Maurici , Mutzner Raphael , Nácher-Rodríguez Beatriz , Tomàs-Burguera Miquel , García-Comendador Julián , Peña Xavier , Calvo-Cases Adolfo , Vallés-Morán Francisco, J
Published: March 2020

A flash-flood event hit in the 9th October 2018 the northeastern part of Mallorca Island, causing 13 casualties. As global change may exacerbate devastating flash floods, comprehensive analyses of catastrophic events are crucial to support effective prevention and mitigation measures. Field-based, remote-sense and modelling techniques were used to evaluate rainfall-runoff processes at catchment scale linked to hydrological modelling. Continuous streamflow monitoring data revealed a peak discharge 442 m3 s−1 with an unprecedented runoff response (lag time, 15’). This very flashy behaviour triggered the natural disaster as a combination of heavy rainfall (246 mm in 10 h), karstic features and land cover disturbances in the Begura de Saumà River catchment (i.e., 23 km2). Topography-based connectivity index and geomorphic change detection were used as a rapid post-catastrophe decision-making tool, playing a key role during the rescue searching tasks. These hydrogeomorphological precision techniques were also applied in combination with Copernicus EMS and ground-based damage assessment illustrating with high accuracy the damage driving factors in the village of Sant Llorenç des Cardassar.  The incorporation of hydrogeomorphological precision tools during Emergency post-catastrophe operational has been revealed as a powerful tool. Then, the simple application of a geomorphometric index from easy-access LiDAR-based topographic data resulted in a rapid identification of deposition zones in the different compartments of a catchment helping in the search and rescue of missing persons. In addition, the evaluation of landforms signature by using UAVs effectively quantified the sediment deposits generated by the flash-flood and/or mobilised by the Emergency operational during the rescue searching tasks.

This work was supported by the research project CGL2017-88200-R “Functional hydrological and sediment connectivity at Mediterranean catchments: global change scenarios –MEDhyCON2” funded by the Spanish Ministry of Science, Innovation and Universities, the Spanish Agency of Research (AEI) and the European Regional Development Funds (ERDF)
What open data tells us - Reconstructing 55 years of global land use/cover change
Authors: Winkler Karina , Fuchs Richard , Herold Martin , Rounsevell Mark
Published: March 2020

People have increasingly been shaping the surface of our planet. Land use/cover change – the most visible human footprint on Earth – is one of the main contributors to greenhouse gas emissions and biodiversity loss and, hence, is a key topic for current sustainability debates and climate change mitigation. To understand these land surface dynamics and its impacts, accurate reconstructions of global land use/cover change are necessary. Although more and more observational data sets are publicly available (e.g. from remote sensing), current land change assessments are still incomplete and either lack temporal consistency, spatial explicitness or thematic detail. Here, we show a consistent reconstruction of global land use/cover change from 1960-2015, using an open data-driven approach that combines national land use statistics with earth observation data of multiple sources and scales. Our land change reconstruction model HILDA+ (Historic Land Dynamics Assessment) accounts for data-derived gross changes within six main land use/cover classes at 1 km spatial resolution: Urban areas, cropland, pastures and rangeland, forest, (semi-)natural grass- or shrubland, other land. As a result, we present yearly land use/cover maps at 1 km spatial resolution, magnitudes and hot spot areas of change. Globally, around 20 % of the land surface – almost three times the size of Brazil - has undergone change within the last 55 years. Further, gross change is about seven times as high as yearly net change extent for forest, cropland and pasture dynamics. We prove that land change studies accounting for net change only can lead to severe underestimations of change extent and frequency. With this purely data-driven approach, we address current research needs of the earth system modelling community by providing new layers of land use/cover change with unprecedented level of detail. Learning from the recent past, understanding how management and land cover dynamics interactively affect the climate is essential for implementing measures of mitigation and sustainable land use policies. In this context, a solid information base can support informed decision-making.
Subducting filaments at fronts in the Alboran Sea: Physical, turbulent and biological evidences.
Authors: Falcieri Francesco Marcello , Dever Mathieu , Freilich Mara , Griffa Annalisa , Schroeder Katrin , Mahadevan Amala
Published: March 2020

Submesoscale instabilities along oceanic fronts can cause water mass intrusions from the surface mixed layer into the stratified pycnocline. These are important drivers of vertical exchange that have a potentially significant impact on the transfer of physical properties and biological tracers.

The CALYPSO (Coherent Lagrangian Pathways from the Surface Ocean to Interior) ONR research initiative focuses on observing and understanding coherent vertical pathways by which vertical exchange occurs. The Alboran Sea (located in the south-western Mediterranean, east of Gibraltar) is well known for its strong density fronts and eddies. During a research cruise, onboard R/V Pourquoi Pas? in early April 2019, we found that fronts in this area support the generation of subducting filaments. Several types of observations (using CTD, uCTD, microstructure profiles, drifters and floats) were collected along numerous cross-front transects over a period of two weeks.

The analysis of the temperature profiles highlighted the presence of several intruding filaments moving along isopycnal surfaces in the proximity of the frontal area. The intrusion signal was also clearly visible in biophysical properties with elevated Chlorophyll-a concentrations, well below the deep chlorophyll maximum, in conjunction with high dissolved oxygen values. From a microstructure point of view, the upper and lower limits of the subducting filaments exhibited high turbulent dissipation rates, with values of O(10-7) W/m2. These dissipation rates are higher than what is generally observed at such depths and point to enhanced mixing activity at the boundaries of the intrusions even along isopycnal surfaces.
Contribution of lakes in the ORCHIDEE land surface model
Authors: Bernus Anthony , Ottle Catherine , Raoult Nina
Published: March 2020

Lakes play a major role on local climate and boundary layer stratification. At global scale, they have been shown to have an impact on the energy budget, (see for example Le Moigne et al., 2016 or Bonan, 1995 ) . To represent the energy budget of lakes at a global scale, the FLake (Mironov et al, 2008) lake model has been coupled to the ORCHIDEE land surface model - the continental part of the IPSL earth system model. By including Flake in ORCHIDEE, we aim to improve the representation of land surface temperature and heat fluxes. Using the standard CMIP6 configuration of ORCHIDEE,  two 40-year simulations were generated (one coupled with FLake and one without) using the CRUJRA meteorological forcing data at a spatial resolution of 0.5°. We compare land surface temperatures and heat fluxes from the two ORCHIDEE simulations and assess the impacts of lakes on surface energy budgets. MODIS satellite land surface temperature products will be used to validate the simulations. We expect a better fit between the simulated land surface temperature and the MODIS data when the FLake configuration is used. The preliminary results of the comparison will be presented.
Infrasound signal characteristics of rock soil landslide and experience with its engineering application
Authors: Fu Xiang , Ban Yuxin , Xie Qiang , He Chunbo
Published: March 2020

As the infrasound signal has the advantages of slow energy attenuation, strong ability to cross obstacles and no need of contact acquisition, it is of great significance to take advantage of the infrasound signal in the process of deformation and failure of rock and soil mass to realize remote rapid monitoring and early warning of geological disasters. The infrasound signal characteristics of soil slope failure and rock under different stress states (compression, shear and tension) were compared by indoor and outdoor tests. The results showed that there was an obvious waveform of infrasound signal at the site of soil slope damage. The infrasound signal appeared mainly in elastic and plastic deformation stages under the compression state, the peak frequency of the infrasound signal was about 7 Hz. The concentration of signal power was slightly less than that under the compression state, and the peak frequency was about 8 Hz. The infrasound signal always associated with the whole loading process under tension state, and there were two bands of frequency center, in which the lower frequency was close to that of the compression test specimen, and the higher frequency was 3 Hz larger. On this basis, using the infrasound characteristics of rock and soil mass failure, the infrasound and other monitoring methods were carried out for Xinpu landslide in Fengjie, Chongqing, China. After the occurrence of the landslide, the infrasound signal characteristics of rock and soil failure were basically the same as those of indoor tests. The low-frequency signals were mainly monitored. At the same time, the monitoring results showed that the peak value of the infrasound signal reached before the mechanical signal, and the mechanical signal was monitored prior to the displacement signal. The infrasound signal can be 3-5 hours ahead of displacement signal. This regularity has important scientific and application value for landslide monitoring and prediction.
Exploring the relationship between phenology and hydrology using Sentinel-2 and terrestrial photography in Mediterranean grasslands
Authors: Gómez-Giráldez Pedro Jesús , Pérez-Palazón María José , Polo María José , González-Dugo María Patrocinio
Published: March 2020

Mediterranean grasslands are an essential component of rural economy as the primary source of fodder for livestock in extensive areas. These annual grasslands present an escape mechanism to cope with the long summer dry season and the recurrent water scarcity events of the Mediterranean climate, completing their life cycle before serious soil and plant water deficits develop. It results in a close link between grass phenology and soil water dynamics. In this work we have explored this relationship using satellite and ground remote sensing (Sentinel-2 (S2) and a terrestrial digital camera) and ground measurements of hydrological variables.

The terrestrial photography was used as a field validator, grass greenness was assessed using the Green Chromatic Coordinate Index (GCC) and key phenological dates were extracted from the variation of this index during a calibration period (December 2017 to May 2019). The evolution of GCC index was highly correlated with soil moisture (SM) dynamic, which is consistent with the water-limited condition of the ecosystem. Some other variables, including vapor pressure deficit, solar radiation, and minimum, medium and maximum air temperatures were inversely correlated with greenness. Rainfall, although positively correlated, presented the lowest coefficient of all analyzed variables. The capability of SM and S2-NDVI to predict the phenology of the grass canopy was assessed by fitting a double-logistic function to the variables time-series and extracting the phenological parameters start of season (SOS), peak of season (POS) and end of season (EOS) using the 50% amplitude method. The comparison with the terrestrial camera resulted in differences less than 10 days for all phenological dates parameters studied (representing less than 5% error within a grass cycle). The behavior of S2-NDVI and SM relationship during four growing seasons was analyzed. It pointed out the synchronized seasonality shown in this system by the vegetation greenness, measured here by the NDVI, and the soil moisture. The higher agreement was found at the beginning and the end of the dry season, with stage changes estimated first by SM, followed by NDVI with a delay between 3 to 10 days. These results highlight the close relationship between these phenological parameters and the soil moisture dynamic under the study conditions, and the capability of satellite data to track these parameters.
An application of stable isotope techniques for the investigation of geographic origin of water–investigation of the Mareza Spring near Podgorica (Montenegro)
Authors: Radulovic Milan , Horacek Micha , Sekulic Goran , Ćipranić Ivana , Živaljević Slobodan , Stumpp Christine , Wyhlidal Stefan
Published: March 2020

Mareza Spring is used for the water supply of Podgorica (capital of Montenegro) since over 70 years. It is located in the central part of Montenegro in the north-western part of Podgorica Valley. The recharge area and origin of groundwater of this karstic source are not known well. This is primarily due to the fact that drainage divides in karst terrains are the unknown and insufficiently examined segments. There are a few hypotheses about the origin of water: 1. from the Zeta River which flows few kilometres north-east from Mareza Spring, 2. from the Morača River which partly sinks at the exit of the canyon (around 10 km east from Mareza Spring), and 3. from the Prekornica Mountain recharge area that is located 10-20 km north-east from the spring (that is a karst plateau with average altitude around 1,000 m asl). Therefore, the isotopic techniques (altitude effect, comparison) could be useful for testing these assumptions. In the present study monitoring of stable isotopes (2H, 18O) in precipitation, surface water and groundwater of this area is carried out to determine the origin of water and adequate protection of Mareza Spring.

 
Identification of moisture source region based on trajectory model analysis and isotopic composition of the precipitation in Debrecen, Hungary
Authors: László Elemér , Palcsu László , Leelőssy Ádám
Published: March 2020

In this study, we focus on the relationship between the water vapor source region and the isotopic composition of the precipitation. The change of isotope characteristics of precipitation depends on the moisture source region. Long-term stable isotope (δ18O, δ2H ) measurements of precipitation were performed in Debrecen, Hungary, between 2001 and 2014. The long-term isotope time series and trajectory modeling are suitable for determining moisture source regions. Backward trajectory analysis was carried out using the Lagrangian Raptor model based on ERA5 atmospheric data. Hourly backward trajectories were calculated for Debrecen for the days with precipitation in the period between 2001-2014.

Based on the study three source regions were identified. Of these, 60% represented the Carpathian Basin, which is where most of the moisture evaporated from near the surface. The remaining 40% of the northwest and southwest were represented by moisture source regions. This means that the isotopic composition of precipitation significantly determines the local and continental effects, i.e. the moisture evaporated from the continental surface contributes significantly to the spatial and temporal variation of the precipitation isotope composition.
Solar activity and its impact on the mid-latitude trough during geomagnetic storms
Authors: Przepiórka Dorota , Matyjasiak Barbara , Rothkaehl Hanna
Published: March 2020

Mid-latitude trough (MIT) is the distinct structure observed in
Earth's ionosphere at high latitudes especially at the nighttimes.
The phenomenon is observed at both hemispheres. As it resides at the
topside ionosphere in sub-auroral region, its behaviour and properties are
highly sensitive to the solar and geomagnetic activity. Generally as the
geomagnetic activity is more pronounced the MIT is observed at lower
latitudes, it also deepens and becomes much more distinct in comparison to
the low magnetic activity periods. MIT responds as well to the rapid
changes in geomagnetic conditions, as are the geomagnetic storms, mainly
caused by the CMEs.
Based on the observations gathered by DEMETER data between 2005 and 2010
years we present a set of geomagnetic storm cases and how the MIT
properties has been changing as the storm evolves. We also discuss how it
corresponds to the current solar activity as their evolutionary history
described by a set of different parameters.
Aerosol effects on shallow cumulus cloud fields in idealised and realistic simulations
Authors: Spill George , Stier Philip , Field Paul , Dagan Guy
Published: March 2020

Shallow cumulus clouds interact with their environment in myriad significant ways, and yet their behavour is still poorly understood, and is responsible for much uncertainty in climate models. Improving our understanding of these clouds is therefore an important part of improving our understanding of the climate system as a whole.

Modelling studies of shallow convection have traditionally made use of highly idealised simulations using large-eddy models, which allow for high resolution, detailed simulations. However, this idealised nature, with periodic boundaries and constant forcing, and the quasi-equilibrium cloud fields produced, means that they do not capture the effect of transient forcing and conditions found in the real atmosphere, which contains shallow cumulus cloud fields unlikely to be in equilibrium. 

Simulations with more realistic nested domains and forcings have previously been shown to have significant persistent responses differently to aerosol perturbations, in contrast to many large eddy simulations in which perturbed runs tend to reach a similar quasi-equilibrium. 

Here, we further this investigation by using a single model to present a comparison of familiar idealised simulations of trade wind cumuli in periodic domains, and simulations with a nested domain, whose boundary conditions are provided by a global driving model, able to simulate transient synoptic conditions. 

The simulations are carried out using the Met Office Unified Model (UM), and are based on a case study from the Rain In Cumulus over the Ocean (RICO) field campaign. Large domains of 500km are chosen in order to capture large scale cloud field behaviour. A double-moment interactive microphysics scheme is used, along with prescribed aerosol profiles based on RICO observations, which are then perturbed.

We find that the choice between realistic nested domains with transient forcing and idealised periodic domains with constant forcing does indeed affect the nature of the response to aerosol perturbations, with the realistic simulations displaying much larger persistent changes in domain mean fields such as liquid water path and precipitation rate. 