bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison between bedload flux from inverse modelling of seismic ground motion data and direct monitoring by Reid bedload samplers
Authors: Lagarde Sophie , Laronne Jonathan , Gimbert Florent , Turowski Jens , Dietze Micha , Halfi Eran
Published: March 2020

Quantification of bedload flux along with its boundary conditions is essential to advance our understanding of rivers and to reduce human and economic threats. However, gaining continuous high resolution empirical data is challenging. Seismic sensors can provide time-resolved quantitative bedload flux data, given adequate data processing. The mechanistic model by Tsai et al. (2012) predicts the power spectral density (PSD) of Rayleigh waves caused by impacts of saltating particles on the river bed, allowing to invert seismic signals to obtain bedload flux. Here we test the robustness of bedload flux inversions of seismic observations against in-situ continuous monitoring of bedload flux and select bedload grain sizes made in the Nahal Eshtemoa, Israel. Proper testing is further ensured by wave propagation (the Green’s function) being fully constrained from active seismic survey experiments. We find that there is a discrepancy of approximately one order of magnitude between the measured and reconstructed bedload flux. We support that this discrepancy can be due to the largest grains, though constituting an infinitely small fraction, generating considerable seismic signals but not being caught by the bedload samplers. It is also possible that this discrepancy is due to model simplification regarding grains in motion. Based on these findings we support that seismic observations may be complementary rather than redundant to in-situ measured bedload flux, because they may give constraints on the fraction of large grains, which is challenging to monitor otherwise.
Eco-development response to climate change and the isostatic uplift of southwestern Finland: Case study of the Nordsund area
Authors: Verstraeten Guido J. M. , Verstraeten Willem W.
Published: March 2020

Remediation of climate change induced by anthropogenic emissions of greenhouse gasses and
it precursors is the main focus today. However, less known is that the environment may also
be subjected to relatively fast geological dynamical phenomena such as the isostatic uplift of
Fennoscandia, parts of Canada and northwestern Russia. This uplift affects the archipelago
along the coast of southwestern Finland and Sweden and causes the relocation of human
activities.
In this study we investigate the on-ground observed regression of the Gulf of Bothnia on the
coasts of southwestern Finland and its implications on the country-side activities in the
framework of the eco-development paradigm. We focus our study on the neighbourhood of
the Nordsund peninsula (60°40’30”N, 21°37’14”E) between Keikvesi and Katavakarinselkä,
representative for the whole Finnish archipelago with an average local isostatic uplift of 9 mm
per year (5 mm in the South and 14 mm in the Merenkurkku area. The Nordsund peninsula
contains a former bay of the Bothnia Sea, called Mustalahti, which is reduced to a lake since
the direct way out of inner land precipitation to the open sea disappeared in the 1980s.
We show that remotely sensed data on vegetation and surface wetness confirms this fast sea
regression and the silting-up of the nearby lakes that drain precipitation to the Gulf. The
changing of the Mustalahti over time and its vegetation is expressed in terms of Normalized
Difference Vegetation Index (NDVI) and the Normalized Difference Wetness Index (NDWI),
derived from Landsat 7 data for May, 12 th 2000 and for Landsat 8 for April, 23 rd 2019
characterized by a 30 m x 30 m pixel resolution. We discuss this changing coastline in the
framework of the Eco-Development paradigm which may rebalance nature, environment,
humans and culture. This paradigm is a valid alternative against the past and present-day
socio-economical dominant approach that contributed to the accelerated change of the Earth’s
climate.
Modelling hydro-climatic suitability of malaria transmission in Africa: new patterns emerge
Authors: Smith Mark , Willis Tom , Alfieri Lorenzo , James William , Trigg Mark , Yamazaki Dai , Hardy Andrew , Bisselink Berny , De Roo Ad , Macklin Mark , Thomas Christopher
Published: March 2020

The availability of water at the ground surface for vector mosquito larval habitats is a critical environmental control of malaria transmission. While ambient air temperature controls the rate of several components of the malaria transmission cycle, extensive laboratory and field studies mean that suitable temperature ranges are well established. In contrast, estimation of surface water availability from current global datasets remains challenging. Instead, monthly rainfall is typically used as a proxy for habitat availability; a threshold of 80 mm per month has gained traction as a proxy for breeding habitat in continental-scale models of malaria climate suitability in Africa and has been applied across the globe. However, since complex and spatially variable hydrological processes (e.g. infiltration, evaporation, soil moisture storage, transfer through and storage in river networks) are omitted, a wide variety of rainfall thresholds are found in the literature that leads to large differences in environmental suitability estimates. Moreover, irrigated areas have been observed to provide suitable year-round habitat for Anopheles mosquitos but are not included in such models.

 

Here we show that across continental Africa, the estimated geographic range of climatic suitability for malaria transmission is more sensitive to precipitation thresholds than the thermal response curves applied. To address this problem and provide a more physical-basis for larval habitat estimation, we use daily climate predictions from seven downscaled general circulation models to run a continental-scale hydrological model (Lisflood) for a process-based representation of mosquito breeding habitat availability. A more complex pattern of malaria climatic suitability emerges as water is routed through drainage networks and river corridors serve as year-round transmission foci. The area estimated to be hydro-climatically suitable for stable malaria transmission is smaller than previous models suggest; however, more people are found in longer-transmission season areas due to higher-density populations along rivers and in irrigated areas. Hydro-climatic predictions of malaria suitable areas show only a very small increase in state-of-the-art future climate scenarios; however, bigger geographical shifts are observed than with most rainfall threshold models and the pattern of that shift is very different when a hydrological model is used to estimate surface water availability for vector breeding. 
Quantifying cloud development from geostationary observations
Authors: Seelig Torsten , Hu Yuanyuan , Deneke Hartwig , Tesche Matthias
Published: March 2020

Clouds and their interaction with short- and longwave radiation represent one of the major uncertainties in our understanding of global climate change. The presence of clouds, particularly of bright low-level water clouds, doubles the Earth’s albedo and they are responsible for half of the solar radiation reflected into space.
Contrary to spaceborne, polar-orbiting observations which are of great detail at fixed time we focus on spaceborne time-resolved measurements of the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) aboard Meteosat Second Generation. We present an innovative method to track warm low-level clouds. The method widely used in experimental fluid mechanics and known as particle image velocimetry (PIV) [1, 2] relies on basic pattern matching. The principle of pattern matching is usually referred to as cross-correlation. It tells us something about displacements and enables the reconstruction of cloud trajectories. Thereby, we quantify cloud development and in combination with the CLAAS-2 dataset [3] we characterize temporal changes of cloud properties.

References
[1] Keane, R. D., Adrian, R. J.: Theory of cross-correlation analysis of PIV images. Applied Scientific Research 49, 191–215 (1992). DOI: 10.1007/BF00384623

[2] Tropea, C., Alexander, L., Yarin, L., (Eds.), F.: Handbook of experimental fluid mechanics. Springer (2007)

[3] Benas, N., Finkensieper, S., Stengel, M., van Zadelhoff, G.-J., Hanschmann, T., Hollmann, R., Meirink, J. F.: The MSG-SEVIRI-based cloud property data
record CLAAS-2. Earth System Science Data 9(2), 415–434 (2017). DOI: 10.5194/essd-9-415-2017
A new 2-moment microphysical scheme for studying hail initiation and growth: model-observation comparison over Southweest of France
Authors: Taufour Marie , Wang Chien
Published: March 2020

Southwestern France is an important wine region where hail-producing storms could cause considerable economic loss. To study the initiation and growth of hailstone, a new microphysical scheme based on the LIMA (Liquid, Ice, Multiple Aerosols, Vié et al., 2016) has been developed. The original LIMA only contains two-moment scheme for rain water, cloud water, and ice crystal. Whereas, the other ice hydrometeors are described by a single-moment scheme. The new scheme adds a full two-moment framework to snow, graupel, and hailstone, thus allowing a better representation of the microphysical processes than the original partial two-moment approach could offer. A large area of southwestern France is actually covered by hailpad network. Results from this network alongside other data thus have been used to evaluate the performance of the single-moment ICE3 scheme, the partial two-moment LIMA scheme, and the new full two-moment scheme in reproducing the evolution of observed hail-producing storm cases. The difference as well as similarity in modeled structures of the storms including hailstone development by different microphysics schemes are examined and will be presented.
Tracking sulfur and its chalcophile allies at Kīlauea Volcano, Hawaii: A story of sulfide saturation, sulfide resorption and magmatic degassing
Authors: Wieser Penny , Jenner Frances , Edmonds Marie , Maclennan John , Kunz Barbara
Published: March 2020

Kīlauea Volcano emits large quantities of sulfur and other chalcophile elements into the troposphere as gas and aerosol particles, with widespread implications for regional air quality. The concentration of these elements in erupting melts is controlled by sulfide saturation, as well as the interplay between the exsolved volatile phase, silicate and sulfide liquids on eruption. Analysis of sulfur and other chalcophile elements (e.g, Ni, Cu, Se, As, Bi, Cd) in melt inclusions and matrix glasses allow deconvolution of these various processes. Olivine-hosted melt inclusions have significantly lower Ni and Cu concentrations than matrix glasses, defining trajectories consistent with sulfide saturation. These observations, when interpreted with the latest generation of sulfide saturation models, demonstrate that sulfides saturate at high MgO contents (10-14 wt%), in contrast to the traditional interpretation that sulfide saturation occurs relatively late at Kīlauea (~ 2 wt% MgO). This apparent discrepancy may be reconciled by considering the behaviour of sulfides during syn-eruptive degassing. The release of ~90% of dissolved sulfur into the vapour phase at low pressures leads to previously sulfide-saturated magmas becoming sulfide-undersaturated, driving the resorption of sulfides in contact with the degassing silicate melt. Sulfide resorption releases Cu, Ni, S and other chalcophile elements into the vapour-melt-(sulfide) system. Comparisons of melt inclusion and matrix glasses reveals that significant quantities of S, Se, Bi and As partition into the exsolved volatile phase. Other elements, such as Ni and Cu, remain largely in the melt. The contrasting behaviour of Se and Cu demonstrates that chalcophile element degassing is largely controlled by fluid-melt, rather than sulfide-melt partitioning. Crucially, sulfide resorption obscures the textural and chemical record of sulfide saturation in matrix glass and whole-rocks, but not in melt inclusions, which are isolated from the late-stage release of chalcophile elements from sulfide breakdown. Sulfide resorption during degassing and eruption provides a significant, but previously unquantified flux of sulfur to the atmosphere (as SO2) at Kīlauea. Careful evaluation of melt inclusion Cu-Ni-S systematics reveals that the total S release during eruptions is ~1450 ppm (1.8 x previous estimates).
Likely and High-End Impacts of Regional Sea-Level Rise on the Shoreline Change of European Sandy Coasts Under a High Greenhouse Gas Emissions Scenario
Authors: Thiéblemont Rémi , Le Cozannet Gonéri , Toimil Alexandra , Meyssignac Benoit , Losada Iñigo
Published: March 2020

Sea-level rise (SLR) is a major concern for coastal hazards such as flooding and erosion in the decades to come. Lately, the value of high-end sea-level scenarios (HESs) to inform stakeholders with low-uncertainty tolerance has been increasingly recognized. Here, we provide high-end projections of SLR-induced sandy shoreline retreats for Europe by the end of the 21st century based on the conservative Bruun rule. Our HESs rely on the upper bound of the RCP8.5 scenario “likely-range” and on high-end estimates of the different components of sea-level projections provided in recent literature. For both HESs, SLR is projected to be higher than 1 m by 2100 for most European coasts. For the strongest HES, the maximum coastal sea-level change of 1.9 m is projected in the North Sea and Mediterranean areas. This translates into a median pan-European coastline retreat of 140 m for the moderate HES and into more than 200 m for the strongest HES. The magnitude and regional distribution of SLR-induced shoreline change projections, however, utterly depend on the local nearshore slope characteristics and the regional distribution of sea-level changes. For some countries, especially in Northern Europe, the impacts of high-end sea-level scenarios are disproportionally high compared to those of likely scenarios.
Alterations in the thermo-haline structure and hydrodynamical circulation within the deltaic regions and continental platforms adjacent to the San Francisco and Parnaiba rivers (NE Brazil) due to the effects of global climate changes.
Authors: Capuano Tonia Astrid , Araujo Moacyr , Silva Marcus , Varona Humberto
Published: March 2020
Total ozone loss during the 2019/20 Arctic winter and comparison to previous years
Authors: Goutail Florence , Pommereau Jean-Pierre , Pazmino Andrea , Lefevre Franck , Clerbaux Cathy , Boynard Anne , Hadji-Lazaro Juliette , Chipperfield Martyn , Feng Wuhu , Van Roozendael Michel , Jepsen Nis , Hansen Georg , Kivi Rigel , Bognar Kristof , Strong Kimberly , Walker Kaley
Published: March 2020

The amplitude of ozone depletion in the Arctic is monitored every year since 1990 by comparison between total ozone measurements of SAOZ / NDACC UV-Vis spectrometers deployed in the Arctic and 3-D chemical transport model simulations in which ozone is considered as a passive tracer.

When SAOZ measurements are missing for various reasons, lack of sunlight, station closed or instrument failure, they are replaced since 2017 by IASI/Metop overpasses above the station. These measurements in the thermal Infrared are available all year around, at all latitudes even in the polar night. IASI data have been compared to SAOZ and to 3-D CTM REPROBUS and the agreement is better than 3% at the latitude of the polar circle.

The method allows determining the evolution of the daily rate of the ozone destruction and the amplitude of the cumulative loss at the end of the winter. The amplitude of the destruction varies between 0-10% in relatively warm and short vortex duration years up to 25-39% in colder and longer ones.

Since a strong and large vortex centred at the North Pole, PSCs and activated chlorine are still present at all levels in the lower stratosphere on January 9, 2020, there is a good probability that a significant O3 loss may happen in 2020. But since, as shown by the unprecedented depletion of 39% in 2010/11, the loss depends on the vortex duration, strength and possible re-noxification, it is difficult to predict in advance the amplitude of the cumulative loss at the end of the winter.

Shown in this presentation will be the evolution of ozone loss and re-noxification in the Arctic vortex during the winter 2019/20 compared to previous winters and REPROBUS and SLIMCAT CTM simulations.
Observed coastal sea level changes in Southeast Asia from retracked altimetry over 2002-present
Authors: Gouzènes Yvan , Léger Fabien , Cazenave Anny , Birol Florence , Passaro Marcello , Nino Fernando , Schwatke Christian , Legeais Jean-François , Benveniste Jérome
Published: March 2020

We present results of contemporary coastal sea level changes along the coasts of different
regions of Southeast Asia derived from a dedicated reprocessing of satellite altimetry data.
This work is performed in the context of the ESA ‘Climate Change Initiative’ sea level project
dedicated to provide altimetry-based sea level time series in the world coastal zones. Here is
focus on Southeast Asian Seas. High-frequency (20 Hz) sea level data from the Jason-1,
Jason-2 and Jason-3 missions are considered. The data are first retracked using the ALES
adaptive leading edge subwaveform retracker and further combined with the X-TRACK
processing system developed to optimize the accuracy of the sea level time series in coastal
oceans. Rates of sea level change are estimated over the period 2002-present along the Jasontracks,
from the open ocean to the coast. Different coastal sea level trend behaviors are
observed over the study period: constant trends from open ocean to the coast, sometimes
decreasing trends, or increasing trends within the last few km to the coast. We compare the
computed coastal trends in Southeast Asia with results we previously obtained in other
regions (Mediterranean Sea, Western Africa, Northeastern Europe). We further discuss the
various small-scale processes able to explain departure of the coastal sea level rate from the
offshore (open ocean) rate.
The Use of a Convection Boundary Condition in the Simulation of a Heat Tracer Experiment Conducted in Bedrock
Authors: Novakowski Kent
Published: March 2020

Heat transfer experiments conducted in the subsurface are usually interpreted using either analytical or numerical models, which incorporate first-type boundary conditions (specified temperature) to introduce the heat into the solution domain. An alternative approach is to use a third-type boundary condition, often refereed to as a convection bc in the heat transfer literature, which includes a heat transfer coefficient to accommodate the exchange of heat between fluid flowing outside the domain to that inside the domain under potential. To explore the impact of this boundary condition, a semi-analytical model was developed for a linear flow system in a discrete rock fracture with advective heat transfer in the fracture and conductive heat transfer in the matrix. To illustrate the influence of the heat transfer coefficient, the model is applied to the results of a heat tracer experiment conducted in a discrete fracture connecting two boreholes in a crystalline rock, with warm fluid injection in one borehole and passive temperature measurement in the other.  The experimental results were also simulated using a similar model having a first-type condition at the injection borehole for comparison. The simulations show that the heat transfer coefficient has a significant influence on the shape of the breakthrough curve and allows for an excellent match with the field data, whereas the model with the first-type condition cannot obtain a match of similar quality. 
Link between transformation rate and overturning in the Iceland Basin and Irminger Sea
Authors: Petit Tillys , Lozier Susan , Josey Simon A. , Cunningham Stuart A.
Published: March 2020

The Atlantic Meridional Overturning Circulation (AMOC), a key mechanism in the climate system, transforms warm and salty waters from the subtropical gyre into colder and fresher waters in the subpolar gyre and Nordic Seas. To measure the mean AMOC and its variability at subpolar latitudes, the Overturning in the Subpolar North Atlantic Program (OSNAP) array was deployed in the summer of 2014. Based on observations through May 2016, the majority of the light‐to‐dense water conversion takes place north of the OSNAP East line, which runs from the southeast tip of Greenland to the Scottish shelf. In this study, we assess the transformation of dense waters in the area located between the Greenland-Scotland Ridge and the OSNAP East section. From 2014 to 2016, the mean overturning within this area is estimated at 6.9 ± 1.3 Sv across σ0 = 27.55 kg m-3, the isopycnal that separates the northward and southward flows. This mean overturning estimate is in close agreement with the value (6.5 ± 1 Sv) derived by applying water mass transformation theory to air-sea buoyancy fluxes from atmospheric reanalysis. However, the large monthly variability of the overturning (standard deviation of 4.1 Sv) cannot easily be attributed to the buoyancy forcing or to variability in the overflow through the Greenland-Scotland Ridge. We explore possible mechanisms that can account for this variability.  
Contribution of Galileo observations to improve the quality of daily and sub-daily earth rotation parameter estimates
Authors: Halilovic Dzana , Weber Robert
Published: March 2020

The European GNSS Galileo became almost fully operational with 22 usable satellites in orbit and two testing satellites on the extended orbit. Since the introduction of the first Galileo satellite in December 2005, it became an important complement in GNSS applications to the already established GPS and GLONASS. The combination of Galileo with GPS observations allows to achieve an increased accuracy of precise parameter estimation.

GNSS-based applications are one of the most important methods to derive estimates of the pole coordinates x, y and the LOD (Length-of-Day). In previous work, the potential to improve GNSS observations for the estimation of hourly earth rotation parameters (ERP), based on a Multi-GNSS approach, has been investigated. The analysis covered a 6 month’s (August 2017 – December 2017) time period and considered a globally distributed network of approximately 160 GNSS stations. For around 75 stable stations, an NNR (No-Net-Rotation) constraint to their ITRF2014 coordinates was applied and precise GPS+Galileo ephemerides provided by ESA were used (based on an improved SRP apriori box-wing model for the Galileo satellites). On top solar radiation pressure coefficients were estimated using the empirical CODE orbit model (ECOM). Two solutions were applied, a GPS-only and a combined GPS+Galileo solution.

Meanwhile a reprocessing of the same time series was performed, based on an upgraded stable GNSS station network. Again, a GPS-only and a combined GPS+Galileo solution was carried out. The processing of the new time series has been extended for the whole year of 2017 and the first half of 2018, to provide more reliable results.

In this presentation, comparisons of 1- and 3-day arc ERP solutions with the IERS reference model IERS2010XY will be examined and discussed. Additionally, the different solution types (GPS-only and GPS+Galileo) from the first and reprocessed run were compared. From both GNSS solutions, amplitude corrections for tidal waves were estimated and analyzed w.r.t. the IERS2010XY reference model.
Pathways and time scales of ocean heat uptake and redistribution in a global ocean-ice model
Authors: Marzocchi Alice , Nurser George , Clement Louis , McDonagh Elaine
Published: March 2020

Changes in regional ocean heat content are not only sensitive to anthropogenic and natural influences, but also substantially impacted by the redistribution of heat, which is in turn driven by changes in ocean circulation and air-sea fluxes. Using a set of numerical simulations with an ocean-sea-ice model of the NEMO framework, we assess where the ocean takes up heat from the atmosphere and how ocean currents transport and redistribute that heat. Here, the strength and patterns of the net uptake of heat by the ocean are treated like a passive tracer, by including simulated sea water vintage dyes, which are released annually between 1958 and 2017. An additional tracer released in year 1800 is also used to investigate longer-term variability. All dye tracers are released from 29 surface patches, representing different water mass production sites, allowing us to identify when and where water masses were last ventilated. The tracers’ distribution and fluxes are shown to capture years of strong and weak convection at deep and mode water formation sites in both hemispheres, when compared to the available observations. Using this approach, which can be applied to any passive tracer in the ocean, we can: (1) assess the relative role of each of the water mass production sites, (2) evaluate the regional and depth distribution of the tracers, and (3) determine their variability on interannual, multidecadal and centennial time scales.
Impacts of ENSO and IOD on Snow Depth over the Tibetan Plateau: Roles of Convections over the Western North Pacific and Indian Ocean
Authors: Zhang Tuantuan , Jiang Xingwen , Tam Chi-Yung , Chen Junwen , Lau Ngar-Cheung , Yang Song , Wang Zunya
Published: March 2020

This is a consensus that snow over the Tibetan Plateau (TP) modulates the regional climate significantly. Possible causes for the interannual variability of snow over the TP, however, are under debate, especially regarding the independent roles of El Niño-Southern (ENSO) and Indian Ocean dipole (IOD). Based on in-situ observational data analyses and model simulations, our study shows that impacts of ENSO and IOD on snow depth (SD) over the TP are different during early winter. In particular, ENSO mostly affects SD over the eastern TP, while IOD affects SD over the central-western TP. Both above-normal snowfall and cold temperature anomaly contribute to deeper-than-normal SD, with the former playing a more important role. Diabatic cooling of the suppressed convection over the western North Pacific that related to the positive phase of ENSO could excite an anomalous cyclonic circulation and strong cold temperature anomalies over the eastern TP. There is an enhanced moisture transported over the eastern TP from the tropics due to the anomalous cyclonic circulation; along with strong cold temperature anomalies, resulting in above-normal snowfall in the eastern TP. On the other hand, anomalous convection over the western Indian Ocean related to the positive IOD could generate a wave-train propagating northeastward and induce an anomalous cyclonic circulation over the central-western TP. The associated anomalous circulation transports extra moisture from the tropics to the central-western TP, providing conditions favorable for more snowfall over the central-western TP. Opposite conditions tend to occur during negative phases of ENSO and IOD.
Influence of sea-ice-derived halogens on atmospheric HOx as observed in springtime coastal Antarctica
Authors: Jones Anna , Brough Neil , Griffiths Paul
Published: March 2020

We present first observations of OH and (HO2 + RO2) carried out in Antarctica outside the summer season. Measurements were made over 23 days in spring at the coastal Antarctic station Halley. Increases in concentrations were evident during the measurement period due to rapidly increasing solar irradiance, and clear diurnal cycles were present throughout. There were also notable differences in air mass composition depending on wind direction. Air masses that had traversed the sea-ice-zone had both higher concentrations of OH and a larger OH:(HO2 + RO2) ratio. We use steady-state kinetic arguments and a 0-D box model to probe the chemical drivers. We find that differences in bromine chemistry, previously measured at Halley, are sufficient to account for the observed differences in OH concentration as well as the ratio. There is some evidence also that chlorine chemistry is influencing concentrations of RO2.

Sea ice in the polar regions is undergoing considerable change. Our results suggest that changes in the characteristics and extent of the sea-ice-zone that lead to changes in abundance of atmospheric halogens, will also result in a change in OH. For example, a shift towards more new sea ice formation, with its higher salinity over multi-year ice, would be expected to increase the abundance of halogens; conversely, overall reduction in sea ice extent would ultimately reduce abundance of halogens. OH radicals play a key role in oxidation reactions that remove pollutants from the atmosphere. Especially given anticipated expansion of industrial activities in the Arctic, this is a further factor to take into account when considering the wider impacts of sea ice loss.
Proposing an implementation of a climate change adaptation strategy at river basin scale. Application to the Jucar river basin.
Authors: Estrela Segrelles Clara E , Pérez Martín Miguel Ángel
Published: March 2020

According to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, warming of the climate system is unequivocal and in recent decades, changes in climate have caused impacts on natural and human systems on all continents and across the oceans. Surface temperature is projected to rise, and rainfall patterns to change. Freshwater resources could be compromised due to climate change, especially in the Mediterranean region. Moreover, extreme events as droughts or floods are expected to occur more frequently.

For all these reasons, we propose the evaluation and implementation of a climate change adaptation river basin plan with the aim of reducing risks and improve resilience. Indeed, one of the goal 13 targets of the Sustainable Development Goals is strengthening resilience and adaptive capacity to climate-related hazards and natural disasters in all countries. The EU Strategy on adaptation to climate change encourage all members to implement adaptation strategies. For instance, climate change adaptation river basin plans are a reality in France, where basin adaptation plans have been published since 2014.

Evaluating risks and propose measures in order to reduce water vulnerability is needed in Jucar river basin (Eastern Spain) where water system is currently stressed. Jucar climate change adaptation basin plan should evaluate the specific qualities the basin has and the risks and vulnerabilities in order to strength water management. For this evaluation, we propose to assess the impact of the spatial distribution of precipitation and temperature within the case study for identifying the most vulnerability areas. Furthermore, the sea level rise will cause affection in groundwater aquifers that should be included on the proposed analysis.
Assessing the seismic hazards associated with one of the largest active thrust sheets: the case of the slowly deforming Western Kunlun mountain range (Xinjiang, China).
Authors: Simoes Martine , Guilbaud Christelle , van der Woerd Jerome , Barrier Laurie , Tissandier Roxane , Li Haibing , Nocquet Jean-Mathieu , Pan Jiawei , Baby Guillaume , Si Jialiang , Tapponnier Paul
Published: March 2020

The Western Kunlun Range (WKR) is a slowly converging orogen located along the northwestern edge of the Tibetan Plateau, facing the Tarim Basin. The recent Mw 6.4 2015 Pishan earthquake along the mountain front recalls that this region remains seismically active, despite little or moderate historical seismicity. Its low deformation rates can be hardly retrieved from current geodetic data, placing limited constraints on the potential interseismic loading of the region. This is particularly critical as recent structural investigations report the existence of an extremely wide (~150-180 km) frontal thrust sheet, whose dimensions would imply the possibility of major M ≥ 8 earthquakes in the case that it is locked and slips during one single seismic event.

To place further constraints on the seismic hazards of this region, we have conducted morphological and structural analyses of active faults to unravel the geomorphic record of active deformation cumulated other multiple seismic events at specific sites. To do so, field observations, seismic profiles and high-resolution Pléiades images and DEMs were combined together with the dating of fluvial terraces. We find that shortening rates have been of 0.5-2.5 mm/yr, with most probable values of ~2 mm/yr over the last ~300-500 kyr. Our detailed morphological investigations further indicate that this shortening is variably partitioned on one or several blind ramps along the mountain front, and from there is transmitted forward all the way to the deformation front, ~150-180 km further north. As such, this extremely wide single frontal thrust sheet stands most probably as the largest active thrust sheet in the world!

Finally, previously published GPS velocity fields highlight a 2-3 mm/yr gradient in horizontal velocities across the WKR and southern Tarim basin when combined and expressed in a stable Tarim reference. Such gradient, unseen from previous analyses, is consistent with our morphological results on shortening rates. Most importantly, this spatial gradient in velocities may suggest that the frontal thrust sheet is presently partly locked, questioning the possibility of mega-earthquakes in the region.
How can Thermospheric Neutral Density (TND) estimates from CHAMP and GRACE accelerometer observations be used to improve empirical models?
Authors: Forootan Ehsan , Farzaneh Saeed , Kosary Mona , Schumacher Maike
Published: March 2020

An accurate estimation of the Thermospheric Neutral Density (TND) is important to compute drag forces acting on Low-Earth-Orbit (LEO) satellites and debris. Empirical thermospheric models are often used to compute TNDs (along-track of LEO satellites) for the Precise Orbit Determination (POD) experiments. However, recent studies indicate that the TNDs of available models do not perfectly reproduce TNDs derived from accelerometer observations. In this study, we use TND estimates from the Challenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) missions and merge them with the NRLMSISE00 from the Mass Spectrometer and Incoherent Scatter family. The integration is implemented by applying a simultaneous Calibration and Data Assimilation (C/DA) technique. The application of C/DA is advantageous since it uses model equation to interpolate and extrapolate TNDs that are not covered by CHAMP and GRACE. It also modifies the model's selected parameters to simulate TNDs that are closer to those of CHAMP and GRACE. The C/DA of this study is implemented daily using CHAMP- and/or GRACE-TNDs, while using the Ensemble Kalman Filter (EnKF) and Ensemble Square-Root Kalman Filter (EnSRF) as merger. Compared to the original model, on average, we found 27% (in the range of 2% to 56%) improvements in the estimation of TNDs. In addition, the results of the C/DA are compared with the TND outputs of the JB2008 model along the CHAMP and GRACE orbits, whose results indicate that the daily C/DA outputs are 60% closer to the observed TNDs (that are not used for the C/DA). Overall, our assessment indicates that EnSRF results in more realistic TND simulation and prediction compared to those derived from EnKF. We show that the improved TND estimates of this study will be beneficial for Precise Orbit Determination (POD) studies.  

Keywords: Thermosphere, Calibration and Data Assimilation (C/DA), NRLMSISE00, Ensemble Kalman Filter (EnKF), Ensemble Square-Root Kalman Filter (EnSRF)
Geomagnetically induced currents in central Europe
Authors: Výbošťoková Tatiana , Švanda Michal , Němeček Zdeněk
Published: March 2020

Eruptive events on the Sun interacts with the magnetosphere and can affect even the Earth-bound structures such as power transmission networks via geomagnetically induced electric currents (GICs). We quantify the geomagnetic activity by the K-index computed from local measurements of the geomagnetic field and investigate its effects on the Czech electric power grid represented as disturbances recorded in the maintenance logs of the power network operators in course of last 12 years. In data sets recording the disturbances on high and very high voltage power lines, we found a statistically significant increase of anomaly rates within tens of days around maxima of a geomagnetic activity compared to the adjacent activity minima. Moreover, we modeled GICs for two (east-west and north-south oriented) high-voltage transmission lines in the Czech Republic and found surprisingly high values of currents, in the order of tens of amperes. Based on in-situ observations, we study propagation and properties of the largest CMEs and their relation to the disturbances in the transmission networks of the Central European countries. Our results provide an evidence that GICs may affect the occurrence rate of anomalies registered on power-grid equipment even in the mid-latitude countries.
Dust impact signals detected by Cassini RPWS instrument at Saturn
Authors: Nouzak Libor , Pavlů Jiří , Vaverka Jakub , Šafránková Jana , Němeček Zdeněk , Píša David , Shen Mitchell , Sternovsky Zoltan , Ye Shengyi
Published: March 2020

Cassini spacecraft spent at Saturn almost half of the Saturn year. During these 13 years in the Saturn magnetosphere, the RPWS (Radio Plasma Wave Science) instrument recorded more than half a million of waveforms with signatures that can be interpreted as dust impact signals. The RPWS antennas in both dipole and monopole configurations operated with 10 kHz or 80 kHz sampling rates during the mission.
We qualitatively and quantitatively analyze the registered waveforms taking into account the spacecraft potential, density of the ambient plasma, magnitude of the Saturn’s magnetic field and its orientation with respect to the spacecraft. The magnetic field orientation is also used for distinguishing between signals resulting from dust impacts and signals produced by solitary waves, which can exhibit similar shapes. The results of analysis are compared with a prediction of the dust impact model that was recently developed on a base of laboratory simulations. The simulations used the reduced model of Cassini that was bombarded with submicron-sized iron grains in the velocity range of 1–40 km/s at the 3 MV dust accelerator operated at the LASP facility of University of Colorado. The model predicts generation of impact signals due to different fractions of collected and escaped electron and ion charges from the impact plasma plume and different timescales of their expansion. The core of the paper is devoted to a discussion of differences between model predictions and observations.
Genesis and Evolution of Black Soil in the Eastern Mediterranean
Authors: Hag Mohamed Husein Hussam , Sahwan Wahib , Lucke Bernhard , Bäumler Rupert
Published: March 2020

Abstract

Knowledge about the genesis and evolution of black soils in the Eastern Mediterranean is vital for sustainable land management as well as for revealing the current and past climate conditions that were decisive for their evolution and development. Hence, it is important to study this type of soil as it only occurs very rarely in the semi-arid region. Answers on the conditions of formation and type of paleoclimate that prevailed during its development can be found in the surrounding environment. In this study, the black soils that currently occur in the Eastern Mediterranean were analyzed in different bioclimatic zones and were found to genetically belong to two soil types: 1-Calcareous black soil (ProperRendzina-Typic Rendolls), 2-Hydromorphic black soil (Haploxerolls). The impact of the relief was obvious on both thickness of the solum and the mollic horizon. Proper Rendzina (Typic Rendolls) occurs on toe slopes and feet slopes, Para-Rendzina (Lithic Rendolls) on shoulders and Chernozems on a flat plain. Regarding the Rendzina, the color reflects the origin of the prevailing parent material from which they are derived: Proper Rendzina forms on limestone, chalk, sandstone, conglomerates, and claystone; Reddish Rendzina on Dolomite and hard limestone, and Grayish Rendzina on Serpentine. It was also found that the Hydromorphic black soils (Haploxerolls, Calcic Chernozems) only occur on calcic marl and lacustrine deposits under saturation conditions and bad drainage in the depressions that formed by the Dead Sea faults. The soil has a thick dark mollic horizon with a high content of organic matter.

Keywords: semi-arid, black soil, Rendzina, Chernozems, eastern Mediterranean.

 
Post-Seismic Deformation in the Northern Antarctic Peninsula Following the 2013 Magnitude 7.7 Scotia Sea Earthquake
Authors: Nield Grace , King Matt , Koulali Achraf , Samrat Nahidul , Steffen Rebekka
Published: March 2020

Large earthquakes in the vicinity of Antarctica have the potential to cause post-seismic deformation on the continent, affecting measurements of displacement and gravity field change from GRACE or those attempting to constrain models of glacial isostatic adjustment.

In November 2013 a magnitude 7.7 strike-slip earthquake occurred in the Scotia Sea around 650 km from the northern tip of the Antarctic Peninsula. GPS coordinate time series from the Peninsula region show a change in rate after this event indicating a far-field post-seismic deformation signal is present. At these far-field locations, the effects of fault after-slip are likely negligible and hence we consider the deformation to be due to post-seismic viscoelastic deformation. Here we use a global spherical finite element model to investigate the extent of post-seismic viscoelastic deformation in the northern Antarctic Peninsula. We investigate possible 1D earth models that can fit the GPS data and consider the effect of including a simple 3D earth structure in the region. These results, combined with previous results showing East Antarctica is still deforming following 1998 Mw 8.2 intraplate earthquake, suggest that much of Antarctica is deforming due to recent post-seismic deformation.
New Energy Balance, New Atmospheric Circulation and New Water Cycle in Western Mediterranean
Authors: Karrouk Mohammed-Said
Published: March 2020

The increase in the Earth's energy balance, due to the surplus of anthropogenic greenhouse gases, has created a warmer earth-based climate regime, widening the excess tropic zone to the poles. The characteristics and rhythms of this climate become unusual, with extreme weather conditions: more frequent heat and cold waves, strong gusts of wind, more severe droughts, and more frequent floods. This is the terrestrial "New Climate".

This situation is characterized by a new thermal distribution: above the ocean, the situation is more in surplus energetic budget, and the land - atmosphere is negative. Warm thermal advection easily reach the Pole, as well as cold advection push deep into Western Mediterranean.

This "New Ground Energy Balance" establishes an atmospheric circulation with an waving character throughout the year, including in winter, characterized by intense energy exchanges latitudinal very active between the surplus and deficit areas on the one hand, and the atmosphere, the ocean and the continent of the other.

The new thermal distribution reorganizes the geography of atmospheric pressure: the ocean energy concentration is transmitted directly to the atmosphere, and the excess torque is pushed northward. The Azores anticyclone is strengthened and is a global lock by the Atlantic ridge at Greenland, which imposes on the jet stream a positive ripple, very strongly marked poleward, bringing cosmic cold advection of polar air masses winter over from Europe to Western Mediterranean. Hence the enormous meridian heat exchanges north-south-north. This is the "New" Meridian Atmospheric Circulation (MAC).

This situation increases the potential evaporation of the atmosphere and provides a new geographical distribution of Moisture: the excess water vapor is easily converted by cold advection to heavy rains that cause floods or snow storms.

Thus, the "New Energy Balance" creates a "New" Meridian-dominated Atmospheric Circulation, which induces excess atmospheric water vapor due to the increase in temperature. Since the hydro-atmospheric capacity has increased, the return to the ground is abundant: It is the "New Water Cycle", which accompanies the “New Energy Balance” of the Earth.
Laboratory Measurements of the Size Distribution and Activation Ratio of Synthetic Ice Nuclei
Authors: Delene David , Peske Eli , Rauscher Mascha , Lubitz Werner
Published: March 2020

Laboratory measurement of the particle size distribution and cloud condensation nucleation activation ratio are conducted using two types of synthetic ice nuclei (IN). New Engineered Organic Nuclei (NEON) are fabricated by fermentation and so-called E-lysis of Gram-negative bacteria, which are havested via centrifugation and resuspended in a NaHCO3 buffer (pH of ~7.8) for final inactivation of lysis escape muntants. NEON is inactivated using 1.25 % (final concentration) glutaraldehyde (GA) and stored in a deep freezer. The NEON with GA solution is atomized using a Sparging Liquid Aerosol Generator (SLAG), which does not sheer or impact the aerosols. The measured size distribution is compared to aerosols produced by the TSI Atmomizer (Model 3076), which impacts generated droplets. The size distribution is measured using a TSI Scanning Mobility Particle Sizer Spectrometer (SMPS) and a TSI Aerodynamic Particle Sizer. A DMT Cloud Condensation Nuclei Counter (CCNC) operated at 0.6 % supersaturation and a TSI Condensation Particle Counter (CPC) is used to measure the activation ratio, which is important to determine effectiveness of the NEON as an immersion ice nuclei. The NEON results are compared to IN produced by burning silver iodine cloud seeding flares.
Geochemical characteristics and source of natural gases in the northern Jizhong Subbasin, Bohai Bay Basin, eastern China
Authors: Liu Nian , Qiu Nansheng
Published: March 2020

The geochemical characteristics and source of natural gases in the northern Subbasin, Bohai Bay Basin, eastern China are investigated systematically by the chemical components, stable isotopic compositions, noble gases isotopic compositions, and geochemical characteristics of associated oils. The results show that several genetic gases are identified in the study area, including thermogenic gas (sapropelic and humic gas), biogenetic gas (primary and secondary microbial gas) and mixed gas. Gases in the shallow strata (Ed, Es1, Es2, Es3 and some Es4 samples) are mainly oil-associated gases, whereas the gases in the deep strata (some Es4 samples, C-P and O) are mainly coal-derived gases and mixed-source gases. Some microbial gases including primary and secondary microbial gases can be identified in shallow Es1 and Es3 reservoirs. The carbon dioxide reduction under anaerobic conditions may be responsible for the anomalously heavy carbon isotope in carbon dioxide and light carbon isotope in methane in the biodegradation gases from the shallow strata (<1900 m), whereas carbon dioxide with heavy isotope compositions in the deeply buried Ordovician reservoirs may be the production of strong acids react with carbonate rocks during acidification and fracturing. The oil-associated gases in shallow strata are derived primarily from the Paleogene Es3 and Es4+Ek bearing sapropelic organic matters, whereas the coal-derived gases in the relatively deep reservoirs are mainly derived from the Paleozoic C-P coal-bearing source rocks and mixed organic matters in Es4+Ek. In addition, the dry gas (secondary cracking gas) in deep to ultra-deep carbonate reservoir may be the potential and favorable exploration field.