bluuebunny/crossref_metadata_2025 huggingface dataset:
Trend analysis of Changing Pattern of Snowfall and Precipitation over the Time Period of 1979 to 2014 in Alpine region of Uttarakhand, Western Himalaya, India
Authors: Pandey Arvind , Palni Sarita
Published: March 2020

Himalayan mountain region lying in the northern piece of Indian sub-continent is among those zones which bears the most geologically fragile situations and are additionally a vault of biodiversity, new water stockpiling and environment administrations. The Himalaya is one of the world’s largest and mostly inaccessible area of glaciers outside the polar regions and provides glacier-stored water to the major perennial rivers of India throughout the year and to their river basins also. Glacier is a large ice mass formed by accumulation, compaction and re-crystallization of snow and firn due to stress of its own weight. Glacier with steep slopes of bedrock may retreat with slower rate or may even advance because downslope movement of glacier will continuously feed ice to lower altitude. Increased retreating rate of glaciers can be considered as an indicator of climate change. In the course of recent three decades, the occurred changes can be explained with exploitative land utilization which is among the primary drivers of changing snow cover, vegetation covers and profitability in western Himalayas locale. In a region where field-based research is tiring because of heterogenous and high elevation, measuring the changes in aforesaid using Remote Sensing techniques can give basic data regarding variating patterns of Snowfall and Precipitation. This paper studies the trend analysis of changing Snowfall and Precipitation patterns using SWAT and MODIS data (1979–2014 and 1999 to Present) over Uttarakhand Himalaya and its association with altitudinal gradient. This paper investigates the trends in maximum (Pmax), minimum (Pmin) & mean (Pmean) Snowfall and Precipitation in the annual, seasonal and monthly time-scales for 54 stations in the 5 regions of Uttarakhand’s Western Himalayan region which are categorized on the basis of elevation, from year 1979-2014. Statistical approaches are used to examine the effect of change in pattern of snowfall and precipitation upon the phenology of vegetation, fresh water ecosystems, agricultural productivity, decreasing snow line, increasing tree line & change in duration of the seasons etc of the study area.
Integrating soil moisture in SCOPE model for improving remote sensing of evapotranspiration and photosynthesis under water stress conditions
Authors: Bayat Bagher , van der Tol Christiaan , Yang Peiqi , Montzka Carsten , Vereecken Harry , Verhoef Wouter
Published: March 2020

A radiative transfer and process-based model, called Soil-Canopy-Observation of Photosynthesis and Energy fluxes (SCOPE), relates remote sensing signals with plant functioning (i.e., evapotranspiration and photosynthesis). Relying on optical remote sensing data, the SCOPE model estimates evapotranspiration and photosynthesis, but these ecosystem-level fluxes may be significantly overestimated if water availability is the primary limiting factor for vegetation. Remedying this shortcoming, additional information from extra sources is needed. In this study, we propose considering water stress in SCOPE by incorporating soil moisture data in the model, besides using satellite optical reflectance observations. A functional link between soil moisture, soil surface resistance, leaf water potential, and carboxylation capacity is introduced as an extra element in SCOPE, resulting in a soil moisture integrated version of the model, SCOPE-SM. The modified model simulates additional state variables: (i) vapor pressure (ei), both in the soil pore space and leaf stomata in equilibrium with liquid water potential; (ii) the maximum carboxylation capacity (Vcmax) by a soil moisture dependent stress factor; and (iii) the soil surface resistance (rss) through approximation by a soil moisture dependent hydraulic conductivity. The new approach was evaluated at a Fluxnet site (US-Var) with dominant C3 grasses and covering a wet-to-dry episode from January to August 2004. By using the original SCOPE (version 1.61), we simulated half-hourly time steps of plant functioning via locally measured weather data and time series of Landsat (TM and ETM) imagery. Then, SCOPE-SM was similarly applied to simulate plant functioning for three cases using Landsat imagery: (i) with modeled ei; (ii) with modeled ei and Vcmax; and (iii) with modeled ei, Vcmax, and rss. The outputs of all four simulations were compared to flux tower plant functioning measurements. The results indicate a significant improvement proceeding from the first to the fourth case in which we used both Landsat optical imagery and soil moisture data through SCOPE-SM. Our results show that the combined use of optical reflectance and soil moisture observations has great potential to capture variations of evapotranspiration and photosynthesis during drought episodes. Further, we found that the information contained in soil moisture observations can describe more variations of measured evapotranspiration compared to the information contained in thermal observations.
A consistent link between drought and forest diebacks across Europe
Authors: Senf Cornelius , Buras Allan , Zang Christian , Rammig Anja , Seidl Rupert
Published: March 2020

Drought has been suggested as major driver of large-scale forest diebacks, but quantitative evidence covering large spatial and long temporal scales is rare for Europe. Combining spatially explicit maps of canopy mortality (i.e., partial or full loss of the dominant tree canopy) generated from Landsat satellite data for the period 1986-2016 and gridded drought indices (0.5° resolution; including vapor pressure deficit, climatic water balance, and precipitation deficit), we report a consistent link between pulses of above-average tree mortality and drought conditions as measured in all three drought indices. As such, we deliver first quantitative evidence that drought conditions can trigger large-scale forest diebacks across Europe’s forests. A future increase in the severity and intensity of droughts as predicted for Europe might thus have unforeseen consequences for Europe’s forests, with large-scale forest diebacks likely becoming more common in the future.
Independent verification of age tie points and planktic reservoir ages deduced for two marine sediment records at the Chilean continental margin by 14C plateau tuning
Authors: Küssner Kevin , Sarnthein Michael , Lamy Frank , Michel Elisabeth , Mollenhauer Gesine , Siani Giuseppe , Tiedemann Ralf
Published: March 2020

On the basis of 14C plateau tuning we established a robust centennial-scale age control for last glacial-to-deglacial sediment sections in two marine sediment cores MD07-3088 and PS97-137 from the upper Chilean continental margin to facilitate a precise stratigraphic correlation between short-term changes in South Pacific oceanography and global paleoclimate signals recorded in ice cores from Antarctica and elsewhere (Küssner et al., in prep.). Age tie points and reservoir ages were derived from tuning a suite of planktic 14C plateaus to a suite of pertinent atmospheric 14C plateaus defined at Lake Suigetsu (Sarnthein et al., 2015). Off central Chile four tephra layers in Core MD07-3088 provide independent proof both for the age assignment and for short-term changes in planktic reservoir age we deduced by means of 14C plateau tuning. Reservoir ages derived from 14C plateau tuning at 11–16.5 cal. ka closely match, one-by-one, four reservoir ages that have been deduced from the difference between the 14C ages of planktic foraminifera associated with the tephra layers in marine sediments and the atmospheric 14C ages of plants associated with paired tephras analyzed nearby on land (Siani et al. 2013). – In Core PS97-137, near to the southern tip of Chile, sediments of the Last Glacial Maximum show a section with distinct lamination of 5-7 layers / cm depth, associated with atmospheric 14C Plateau 6a by plateau tuning. A rough count of the layers in the 160 cm long sediment section of the planktic 14C Plateau 6a gives a number that comes extremely close to the ~900 year-long time span of the atmospheric 14C Plateau 6a, thus provides independent proof for both the accuracy of the time interval assigned to correlated atmospheric ‘Plateau 6a’ and the approach of plateau tuning in general.

 

Küssner et al., Paleoceanography, in prep.,

Sarnthein et al., Radiocarbon, 2015, 57 (1), 129–151.

Siani et al., 2013, Nature comm., 4, 2758.
The Relationship Between Electron-Only Magnetic Reconnection and Turbulence in Earth’s Magnetosheath
Authors: Stawarz Julia E. , Eastwood Jonathan P. , Phan Tai , Gingell Imogen L. , Mallet Alfred , Shay Michael A. , Sharma Pyakurel Prayash , Burch James L. , Ergun Robert E. , Giles Barbara L. , Gershman Daniel J. , Le Contel Olivier , Lindqvist Per-Arne , Strangeway Robert J. , Torbert Roy B. , Argall Matthew R. , Fischer David , Magnes Werner
Published: March 2020

The Earth’s magnetosheath is filled with small-scale current sheets arising from turbulent dynamics in the plasma. Previous observations and simulations have provided evidence that such current sheets can be sites for magnetic reconnection. Recently, observations from the Magnetospheric Multiscale (MMS) mission have revealed that a novel form of “electron-only” reconnection can occur at these small-scale, turbulence-driven current sheets, in which ions do not appear to couple to the reconnected magnetic field to form ion jets. The presence of electron-only reconnection may facilitate dissipation of the turbulence, thereby influencing the partition of energy between ions and electrons, and can alter the nonlinear dynamics of the turbulence itself. In this study, we perform a survey of turbulent intervals in the Earth’s magnetosheath as observed by MMS in order to determine how common magnetic reconnection is in the turbulent magnetosheath and how it impacts the small-scale turbulent dynamics. The magnetic correlation length, which dictates the length of the turbulent current sheets, is short enough in most of the examined intervals for reconnection with reduced or absent ion jets to occur. Magnetic reconnection is found to be a common feature within these intervals, with a significant fraction of reconnecting current sheets showing evidence of sub-Alfvénic ion jets and super- Alfvénic electron jets, consistent with electron-only reconnection. Moreover, a subset of the intervals exhibit changes in the behavior of the small-scale magnetic power spectra, which may be related to the reconnecting current sheets. The results of the survey are compared with recent theoretical work on electron-only reconnection in turbulent plasmas.
Electron drift echoes induced by negative solar wind dynamic pressure pulses
Authors: Ma Xiaohan , Zong Qiugang , Hao Yixin , Claudepierre Seth , Liu Ying
Published: March 2020

Sudden dropouts of the relativistic electron fluxes with drift echoes are closely related to a positive solar wind dynamic pressure pulse, such as an interplanetary shock impact on the magnetosphere. In this study, we further examine how magnetospheric energetic particles response to a negative solar wind dynamic pressure pulse on the 11th May 2017. During this event, sudden dropouts of energetic electron fluxes with an energy of 200 keV∼750 keV and enhancements of the relativistic electron fluxes of 0.85 MeV∼2.7 MeV were observed simultaneously by both Van Allen Probes. The periodic electron flux dropout-recovery or enhancement-decay signatures, which are attributed to electron drift behaviors, exhibited energy dependence. Based on the electron phase space density profile and the induced electric field variation, we interpreted this phenomenon as the consequence of radially outward transportationss of electrons caused by the electric field impulse induced by the negative dynamic pressure pulse.
Effects of potential factors on changes in surface solar radiation in East China over recent decade
Authors: Wang Qiuyan , Zhang Hua , Wild Martin
Published: March 2020

Previous studies have documented that the surface solar radiation (SSR) over most regions of China has shifted from the ‘global dimming’ since the 1950s to the ‘global brightening’ after 2005. In this paper, the potential factors that affect the annual trends of SSR over East China from 2005 to 2018 based on different satellite-derived products are analyzed. Then, due to the lack of long-term various aerosol species from observation data, the focus of this study is to calculate the contributions from direct effects of different types of cloud fraction on SSR relative to the effects of total cloud fraction over East China during the same period using a BCC_RAD radiative transfer model. The results show that clouds and aerosols are the primary factors that affect the SSR over East China from 2005 to 2018, followed by water vapor and ozone.

The annual mean all-sky SSR from 2005 to 2018 is significantly increased over the North China Plain, Northeast China, Yunnan, and Eastern Sichuan provinces, with the increases up to 0.6 W m-2 yr-1. This is probably due to the combined reductions of aerosols and clouds during this period, but clouds even play a more important role over Shanxi and northern Shaanxi. Changes in aerosols dominate the increase of SSR over Hunan, Jiangxi, and Fujian provinces, whereas clouds contribute more to the decreases of SSR over Guangdong, Guangxi, Guizhou, and Zhejiang provinces. Meanwhile, the simulations indicate that the marked annual mean decreases in high cloud fraction, especially for low cloud fraction, are the main causes of simulated increases in SSR due to total cloud fraction over most regions of East China, while the increases in high, medium-high, especially for medium-low cloud fraction, play more important roles in reductions of SSR over southern China. Moreover, the direct effects of various types of cloud fraction on changes in SSR for each season are also examined. It seems that the direct effects of low cloud fraction on SSR are likely the strongest among all kinds of clouds. Take southern China as an example, the direct effects of medium-low and low cloud fraction are stronger for spring and autumn, while contributions from low cloud fraction are largest in winter. However, the combined increases in high, medium-high, medium-low cloud fraction exceed decreases in low cloud fraction, thus causing the reduction in SSR in summer. This study highlights that different types of clouds may have different impacts on SSR not only on the annual mean scale but also on seasonal scales.

Keywords: surface solar radiation, aerosols, different types of cloud fraction
Intercomparison of terrestrial water budgets in EURO-CORDEX and TSMP evaluation runs
Authors: Eltahan Mohamed , Goergen Klaus , Furusho-Percot Carina , Kollet Stefan
Published: March 2020

Water is one of Earth’s most important geo-ecosystem components. Here we present an evaluation of water cycle components using 12 EURO-CORDEX Regional Climate Models (RCMs) and the Terrestrial Systems Modeling Platform (TSMP) from ERA-Interim driven evaluation runs. Unlike the other RCMs, TSMP provides an integrated representation of the terrestrial water cycle by coupling the numerical weather prediction model COSMO, the land surface model CLM and the surface-subsurface hydrological model ParFlow, which simulates shallow groundwater states and fluxes. The study analyses precipitation (P), evapotranspiration (E), runoff (R), and terrestrial water storage (TWS=P-E-R) at a 0.11degree spatial resolution (about 12km) on EUR-11 CORDEX grid from 1996 to 2008. As reference datasets, we use ERA5 reanalysis to represent the complete terrestrial water budget, as well as the E-OBS, GLEAM and E-Run datasets for precipitation, evapotranspiration and runoff, respectively. The terrestrial water budget is investigated for twenty catchments over Europe (Guadalquivir, Guadiana, Tagus, Douro, Ebro, Garonne, Rhone, Po, Seine, Rhine, Loire, Maas, Weser, Elbe, Oder, Vistuala, Danube, Dniester, Dnieper, and Neman). Annual cycles, seasonal variations, empirical frequency distributions, spatial distributions for the water cycle components and budgets over the catchments are assessed. The analysis demonstrates the capability of the RCMs and TSMP to reproduce the overall characteristics of the water cycle over the EURO-CORDEX domain, which is a prerequisite if, e.g., climate change projections with the CORDEX RCMs or TSMP are to be used for vulnerability, impacts, and adaptation studies.
GNSS and VLBI integrated processing at the observation level
Authors: Wang Jungang , Balidakis Kyriakos , Ge Maorong , Heinkelmann Robert , Schuh Harald
Published: March 2020

The terrestrial and celestial reference frames, which serve as the basis for geodesy and astronomy, are mainly determined and maintained by space geodetic techniques such as Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), Global Navigation Satellite Systems (GNSS), and DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite). These techniques are also used together to determine the Earth Orientation Parameters (EOP), which are very important for precise positioning, navigation and timing. Currently, the combination of all these techniques is done on the parameter level (ITRF) or on the normal equation level (DTRF), which are well-known and convenient methods but may suffer from some inconsistency.

Unlike the combination on the parameter or normal equation levels, the integrated processing at the observation level exploits the lengths and unique features of different techniques, and is valuable in determining homogeneous reference frames and EOP, and to connect the terrestrial, celestial, and dynamic frames. We are applying the integrated GNSS, VLBI and SLR data processing in the current Positioning And Navigation Data Analyst (PANDA) software, which aims on processing multi-geodetic techniques on the observation level. We present the strategy and current status of the integrated GNSS and VLBI processing and demonstrate the benefit of integrating GNSS for VLBI using 14 years of VLBI intensive sessions (2001-2014) and five CONT campaigns (2005-2017). We discuss the impact of applying tropospheric tie and local tie in the integrated processing.
Response of Decagon 10HS soil water content sensor to different porous media
Authors: Provenzano Giuseppe , Gugliuzza Giovanni , Duarte Guedes Cabral de Almeida Ceres
Published: March 2020

Optimizing irrigation management requires increasing the accuracy of moisture monitoring in soils or substrates, especially when it depends on electronic sensor readings. Substrates are widely used in horticulture, for growing urban ornamental plants, as well as on green roofs. Due to the lack of information about the accuracy of soil water content sensors on substrates, this research was carried out to evaluate the accuracy of the 10HS sensor (Decagon Devices Inc., Pullman, WA) to estimate soil water content (SWC) in organic substrates and mineral soil. The study was carried out at the Hydrology Laboratory of the University of Palermo. The sensors were inserted into substrates or soil in conical vessels (4 dm3 volume), drilled at the base to measure the drained volume and covered with a transparent film to limit surface evaporation. For both the substrates (A and B) and the mineral soil (C), a known amount was placed in the vessel and compacted to a value of bulk density equal to 0.177 g cm-3, 0.471 g cm-3, 1.480 g cm-3, respectively. The sensors were connected to a CR1000 datalogger (Campbell Scientific Inc., Logan, UT), which allowed the data acquisition and storage. The tests were conducted by wetting the samples with the progressive addition of known volumes of water (about 40 cm3) that were evenly distributed over the sample surface. After the end of the redistribution process of water applied to the container, the sensor readings were acquired. SWC monitoring was performed until reaching the value corresponding to the field capacity. The calibration equation recommended by the sensor manufacturer systematically underestimated the values of SWC of about 5% or more when the substrate A and B were used. On the other hand, when evaluating the sensor performance in the mineral soil (C), it was observed that the errors associated with the manufacturer's equation resulted in ±5%. Therefore, for both substrates specific calibration is necessary to improve the sensor’s accuracy, even accounting for the bulk density; on the other hand, for the mineral soil, the manufacturer's equation can be considered suitable.
Community awareness of climate change and urban flood risk: the case of the Simeto River Basin
Authors: Nanni Paola , Musumeci Rosaria Ester , Peres David J. , Cancelliere Antonino
Published: March 2020

Increased urbanization is causing evident negative consequences on the hydrological cycle. In particular, the increase of impervious surfaces is having a strong impact on the water cycle, amplifying the risk of urban floods. These impacts can get even worse for potential climate change impacts. The urban areas of the Simeto Valley, the largest river valley in Sicily (Italy), has been repeatedly hit by heavy rains in the last decades that caused urban flooding causing several problems and, in some instances, threats to population. The threats seem to derive also from a low awareness of the population on the correct behavior to have in potentially dangerous situations. Hence, it seems of key importance that residents develop and internalize a “culture of risk awareness”. The Life SimetoRES Project represents an opportunity to stimulate the development of a responsible and resilient community and at the implementation of best practices for storm water management. In the Simeto River Valley community has started in the recent decades to formally have an identity (for instance, by signing a River Agreement) and has already supported initiatives in the responsible and participatory co-management of the territory. Thus, this Valley represents an excellent context to investigate this problem and to understand the involvement of the citizens in solving climate change and urban floods. In order to maximize the effectiveness of the communication campaigns and the actions to safeguard the community, a study through a survey on the climate change and risk perception in 11 municipalities has been carried out, collecting 1143 answers. Starting from the current hydrogeological risk, quantified by the Flood Risk Management Plan, the goal was to identify the perception and the awareness of the citizens. A section of the questionnaire involved the direct experience of the residents during rain events, their relationship with the alert system and their knowledge of the correct behavior in case of flood. Finally, the survey investigated the willingness of citizens to implement adaptation actions in their own municipality and in their homes. The results show that over 52% of citizens is not aware of the real use of the infrastructures devised for urban drainage and only the 30% feels responsible about mitigation of flooding risk. Inaccurate weather warnings can endanger more inhabitants who don't trust the alert system. The results show that it is necessary to make incisive actions to educate people, especially in school age, on the correct behavior to take in case of urban flooding, and encourage citizens to acknowledge themselves as an active part of the mechanism of their own and community safety.
Reconstructing the Holocene paleoenvironment of the semi-arid Shiraki Plain of eastern Georgia – a center of settlement activity during the Late Bronze and Early Iron age
Authors: Kirkitadze Giorgi , Elashvili Mikheil , Navrozashvili Levan , Lobjanidze Mikheil , Losaberidze Levan , Koff Tiiu , Fischer Markus L. , Skokan Anna , Khosravichenar Azra , von Suchodoletz Hans
Published: March 2020

Studying of the interactions between past environmental changes and former human societies delivers key information to understand the future evolution of landscapes under changing environmental conditions and increasing human stress. The combination of these two factors is especially critical for fragile landscapes such as drylands, where even small-scale climatic or anthropogenic factors can have relatively large effects on the landscape dynamics.

Holocene paleoenvironmental changes on the Shiraki Plain, located in Eastern Georgia (South Caucasus), were studied. The selected site is characterized by semiarid climate conditions (annual precipitation <500 mm per year) and an open dry steppic landscape today. Currently the area is devoid of settlements, due to absence of water resources. However, recent archaeological data collected using remote sensing and ground-proven by ongoing archaeological excavations, delivered evidences of an active former human inhabitation of this area mostly during the Late Bronze - Early Iron Ages. Several large, city-type settlements of the given period that were identified on the Shiraki Plain suggest the existence of early state formation under favorable environmental conditions.

During the conducted study we have combined stratigraphical-sedimentological investigations of sediments using drilling cores, trenches and laboratory analyses with high-resolution D-GPS measurements in the RTK mode, remote sensing using drone photogrammetric surveys, paleoecological investigations, and hydrological modeling. Our initial results clearly support the hypothesis of a large shallow lake in the center of the Shiraki Plain that was surrounded by the Late Bronze and Early Iron Age settlements. Therefore, the regional water balance of that period was obviously more positive than today. Furthermore, our investigations indicate that this period of high settlement intensity was characterized by intensive soil erosion processes that washed away the dominant Chernozem soils.

Altogether, our investigations suggest a tipping point of the landscape evolution dynamics that must have been crossed during the Late Bronze and Early Iron period, leading to the current dry steppic landscape. This also provides key information to reconstruct the archaeological past of the region, and to address the main question of rapid depopulation and further abandonment of this area.
Role of grain size reduction in formation and inversion of oceanic detachment faults
Authors: Liu Mingqi , Gerya Taras , Bercovici David
Published: March 2020

Oceanic detachment faults are large and long-lived (1-2 Myr), forming at slow- and ultraslow- mid-ocean ridges. They can expose lower crustal gabbroic rocks and mantle peridotite in the seafloor, recognized as oceanic core complexes (OCCs). Mechanical models proposed that detachment faults originate at high angle and, as fault offset increases, are rotated flexurally to an inactive low-angle configuration. Previous studies showed that long-lived detachment faults need a rheological boundary for the offset: (1) an alteration front; (2) the brittle-plastic transition (BPT); (3) the boundary between gabbro intrusions and weakened hydrated peridotite; or (4) low magma supply.  In order to better understand the rheological behavior of oceanic detachments, we investigate numerically potential effects of ductile weakening controlled by grain size reduction on the oceanic detachment faults formation as well as on their subsequent inversion during the Wilson cycle. We employ 3D thermomechanical numerical models with a composite rheology consisting of diffusion and dislocation creep. In our model, oceanic crust deforms in a brittle manner and its strength is controlled by fracture-related strain weakening and healing. In contrast, the lithospheric mantle deforms according to the dry olivine flow law, as a mixture of grain size-dependent diffusion and dislocation creep. Numerical results show that ductile weakening induced by grain size reduction could indeed notably influence both the style of detachment faulting and the fault dipping angles in the depth of the BPT. Grain size has a great effect on the offset of detachment faults and the formation of megamullions and controls the place of new subduction initiation below the BPT. We systematically investigate the influence of the thermal structure, initial grain size and spreading rate on the characteristic oceanic detachment fault pattern. In addition, we also study effects of these parameters on the final inversion of detachment faults during induced intra-oceanic subduction initiation.
The impact of the Messinian Salinity Crisis on marine biota
Authors: Agiadi Konstantina , Hohmann Niklas , Carnevale Giorgio , Gliozzi Elsa , Faranda Constanza , Lozar Francesca , Harzhauser Mathias , Iliopoulos George , Caruso Antonio , Kontakiotis George , Taviani Marco , Mancini Alan Maria , Borghi Enrico , Bajo Campos Ildefonso , Moissette Pierre , Thivaiou Danae , Zarkogiannis Stergios , Besiou Eva , Garcia-Castellanos Daniel , Camerlenghi Angelo
Published: March 2020

The Messinian Salinity Crisis (MSC) was the greatest paleoenvironmental perturbation the Mediterranean has ever seen. The literature is abundant in hypotheses on the repercussions of the MSC on organisms. However, all these are based on incomplete and still uncertain scenarios about the MSC evolution, as well as on the assumption that such a paleoenvironmental perturbation must have completely reset marine biota. Having prevailed for many decades now, this assumption has leaked from paleontology and geosciences to biological sciences, with numerous studies taking this scenario for granted instead of using it as a starting hypothesis to be tested. Here, we review and revise the marine fossil record across the Mediterranean from the Tortonian until the Zanclean to follow the current rules of nomenclature, correct misidentifications, and control for stratigraphic misplacements. We examine the composition of marine faunas, both taxonomically and considering the function of each group in the marine ecosystem and the transfer of energy through the marine food web. Specifically, we investigate the following functional groups: 1) primary producers, 2) secondary producers, 3) primary consumers, 4) secondary consumers, and 5) top predators. Our study includes sea grasses, phytoplankton, corals, benthic and planktonic foraminifera, bivalves, gastropods, brachiopods, echinoids, bryozoans, fishes, ostracods, and marine mammals. We calculate biodiversity indexes to provide independent evidence quantifying to what degree the marine fauna underwent:

A drop of overall regional biodiversity of the Mediterranean due to environmental stress during the Messinian.

A taxonomic and functional change between the Tortonian, Messinian, and the Zanclean, that is before and after the MSC, as well as during the precursor events to that actual crisis taking place after the Tortonian/Messinian boundary.

The onset of the present-day west-to-east decreasing gradient in species richness, which has been related to the sea temperature and productivity gradients and the distance from the Gibraltar connection to the Atlantic.
Tsunami on Mars: Implications for the duration and timing of a northern ocean
Authors: Costard Francois , Rodriguez José Alexis Palmero , Séjourné Antoine , Lagain Anthony , Clifford Steve , Ormö Jens , Bouley Sylvain , Kelfoun Karim , Lavigne Franck
Published: March 2020

The duration and timing of a northern ocean is a key issue in understanding the past geological and climatic evolution of Mars. Mars experienced its greatest loss of H2O between the Noachian and Late Hesperian (~10 m Global Equivalent Layer, Jakosky et al., 2017) roughly the same amount that is thought to have been added to the global inventory by extrusive volcanism over the same time period (Carr and Head, 2015). Thus, the total inventory of water was probably similar during these two epochs. But, the ocean during the Late Hesperian was smaller in extension than the ocean during the Noachian– with significant implications for the potential origin and survival of life. Here we examine the implications of the existence of a Late Hesperian/ Early Amazonian ocean on the planet’s inventory of water (and especially liquid water) and its variation with time. Our previous work (Rodriguez et al., 2016; Costard et al., 2017) concluded that the most plausible explanation for the origin of the Thumbprint Terrain (TT) lobate deposits, with run-ups, found along the dichotomy boundary, especially in Arabia Terra, was tsunami deposits. This supports the hypothesis that an ocean occupied the northern plains of Mars as recently as ~3 billion years ago. Furthermore, Costard et al (2017) produced a tsunami numerical model showing that the TT deposits exhibit fine-scale textural patterns due to the wave’s interference patterns resulting from interactions with the coastal topography. More recently, we suggested that the unusual characteristics of Lomonosov crater (50.52°N/16.39°E ) in the northern plains are best explained by the presence of a shallow ocean at the time of the impact (Costard et al., 2019). Interestingly, the apparent agreement between the age of the Lomonosov impact and that of the TT unit (~3 Ga), strongly suggests that it was the source of the tsunami (Costard et al., 2019). Our preliminary assessment indicates that this impact-generated tsunami required a mostly liquid ocean and because of the high latitude location of the Lomonosov crater site, our results strongly imply relatively warm paleoclimatic conditions. Our conclusions highlight the need for more sophisticated climate models.
The effect of correlated permeability on spatiotemporal distribution of microseismic events in a conceptual model of fluid-induced seismicity
Authors: Khajehdehi Omid , Karimi Kamran , Davidsen Jörn
Published: March 2020

Seismic hazard due to fluid invasion in hydraulic fracturing, wastewater disposal, and enhanced geothermal systems has become a concern for industry and nearby residents. One of the challenges associated with this seismic hazard is the estimation of the spatial effects of these industry operations. Based on a large set of real-world fluid-induced seismicity catalogs, it was recently found that the spatial decay of seismic activity with distance from injection wells exhibits two typical behaviors: short-range decay and long-range decay. The distinction between the two groups can be captured by the exponent in the seismicity density but the underlying origin remains unknown. Here, we introduce a novel conceptual model that not only can capture the observed frequency magnitude distribution of fluid-induced seismic events but also explains different spatial decay exponents observed. In particular, previous models of fluid-induced seismicity have assumed that the permeability and porosity field is either uniform or random and spatially uncorrelated. However, power-law scaling in the spatial frequency power spectrum of well-logs, S(k)∝1/k^β, has been observed for many different physical properties of rocks such as sonic velocity, porosity, and log(permeability). Our model takes advantage of this by introducing a spatially correlated field for porosity and permeability. Our analysis shows that increasing β can decrease the spatial decay exponent, leading to more seismic activity at larger distances from the injection site. In particular, our model explains the two different types of behavior in the spatial distribution of fluid-induced microseismic events as a consequence of different correlations in permeability.
Soil Organic Carbon Distribution and Isotope Composition Response to Erosion in Cropland under Soybean/Maize Production
Authors: McCarty Greg , Li Xia
Published: March 2020

Soil erosion and deposition patterns can affect the fate of soil organic carbon (SOC) in agroecosystems. Topographic constraints affect soil redistribution processes and create spatial structure in SOC density. We combined isoscape (isotopic landscape) analyses for δ13C and cesium-137 (137Cs) inventory via digital terrain analysis quantifying SOC dynamics and soil redistribution patterns to gain insight on their responses to topographic constraints in an Iowa cropland field under soybean/maize (C3/C4) production. Additionally, historic bare soil orthophotos were used to determine soil carbon distribution before the 1960s (prior to global 137CS fallout). Topography‐based models were developed to estimate 137Cs inventory, SOC density, and δ13C distributions using stepwise principal component regression. Findings showed that spatial patterns of SOC were similar to soil erosion/deposition patterns with high SOC density in depositional areas and low SOC density in eroded areas. Soil redistribution, SOC density, and δ13C signature of SOC were all highly correlated with topographic metrics indicating that topographic constraints determined the spatial variability in erosion and SOC dynamics. The δ13C isoscape indicated that C3‐derived SOC density was strongly controlled by topographic metrics whereas C4‐derived SOC density showed much weaker expression of spatial pattern and poor correlation to topographic metrics. The resulting topography‐based models captured more than 60% of the variability in total SOC density and C3‐derived SOC density but could not reliably predict C4‐derived SOC density. This study demonstrated the utility of exploring relationships between δ13C and 137Cs isoscapes to gain insight on fate of SOC within eroding agricultural landscapes.
A critical evaluation of present flood hazard maps in Southwest Germany using epigraphic marks and historical written data
Authors: Bösmeier Annette Sophie , Himmelsbach Iso , Glaser Rüdiger
Published: March 2020

Engraved in stone or attached as metal plates to bridges or house walls, flood marks are mostly publicly accessible symbols of high-water level and form part of the cultural heritage. They serve as tangible representations of the extent of past floods and are thus regarded a medium which can raise public risk awareness and contribute to a collective risk memory. Moreover, epigraphic marks are often regarded a valuable source of information on the frequency and magnitude of historical extreme events. However, a flood mark´s informational value may be considered too rudimentary, and the large number of potential error sources is a challenge that often cannot be fully resolved. We therefore conducted a multi-temporal study in the Kinzig catchment, Southwest Germany, in order to, firstly, test for the credibility and the temporal continuity of flood marks. Secondly, we used the knowledge gathered to verify the current flood hazard maps (FHM). For this study, more than 60 flood marks corresponding to 14 events since the beginning of the 19thcentury were checked and/or mapped in three communities in the upper and middle catchment. A detailed historical survey of flood marks dating back to the early 20th century provided a unique opportunity to assess the preservation of marks as well as the extent of relocation since that time. The flood mark heights were then compared with the flooding depths of the modelled FHM for floods between HQ10 and HQextreme at the respective locations. The gauge record was additionally included to assign return periods to the more recent events. Altogether, a high relative agreement between flood marks and the FHM was found in this systematic study, particularly for events during the 20th century. The extreme extents of some events within headwater catchments documented both by epigraphic marks and further documentary sources however appear to be underestimated by the FHM.
Cenozoic growth of West Kunlun Mountains and tectono-sedimentary evolution of adjacent SW Tarim Basin-New spatial model based on seismic data
Authors: Liu Wenhang , Krzywiec Piotr , Mazur Stanisław , Meng Fanwei , Zhuo Qingong , Chen Zhuxin
Published: March 2020

Kunlun Mountains, SW part of the Tarim Basin and S edge of the Bachu Uplift in central Asia collectively form the northernmost segment of the vast Cenozoic deformation zone and associated depositional areas formed in course of the India – Euroasia collision. Five seismic transects from the SW Tarim Basin (Yechang - Hotan area) calibrated by deep wells were used in order to assess lateral variations of a structural style and syn-tectonic sedimentation in this part of the basin. Pre-Cenozoic substratum of SW Tarim Basin is formed by crystalline basement covered by Paleozoic strata, with important mid-Cambrian evaporites (Awatage Formation) that served as first, deep detachment level. Cenozoic sedimentary infill consists of several kilometers of shallow water to terrestrial clastics with Paleogene evaporites of the Bashiblake Formation at their base. Paleogene evaporites acted as a second, shallow detachment. Mid – late Miocene to Quaternary wedging along the front of the Kunlun Mts., associated with formation of a large-scale duplex consisting of slivers built of Precambrian to Permian rocks, resulted in progressive, laterally variable uplift of the S margin of the Tarim Basin documented by well-preserved growth strata that have been also described in the field. Jade Anticline, large intra-basinal structure that is located in the central part of the Tarim Basin, previously interpreted as a regional wrenching zone, was reinterpreted as a thin-skinned syn-depositional “fish tail” structure, detached in the Paleogene evaporites and formed in Quaternary above local basement elevation. Northernmost late Miocene compressional deformations have been recognized along the S edge of the Bachu Uplift in its Western and central segment. They formed due to complex interplay of thick-skinned basement reverse faulting responsible for regional elevation of basement blocks, and two types of thin-skinned thrusting: southward directed thrusting detached within the mid-Cambrian evaporites and northward directed thrusting detached within the Paleogene evaporites. Compressional deformations along the S edge of the Bachu Uplift are diminishing and eventually disappearing towards the East. All these findings point to significant transfer of compressional stresses into the far foreland of the W Kunlun Mountains and laterally variable tectonic coupling between the Tibet Plateau and central part of the Tarim Basin.

Seismic data used in this study was kindly provided by China National Petroleum Corporation (PetroChina). IHS Markit is thanked for providing academic license of Kingdom seismic interpretation software.
Variation of the tectono-magmatic activity along the Reykjanes Ridge: Influence of the Iceland hotspot on the accretionary processes
Authors: Le Saout Morgane , Devey Colin , Palgan Dominik , Lux Thorsten , Petersen Sven , Þórhallsson Daníel , Tomkowicz Adrianna , Brix Saskia
Published: March 2020

The Reykjanes Ridge is a 900 km long oblique slow-spreading ridge, formed by individual “en echelon” axial volcanic ridges (AVR), directly under the influence of the Iceland hotspot. From the Reykjanes Peninsula to the Bight fracture zone, the Reykjanes Ridge shows variations in lava chemistry, crustal thickness, thermal structure and ridge morphology, which has been attributed to this influence. Our study focuses on four areas of the ridge mapped and sampled during the cruise MSM75 in 2018. The northern area is characterized by the only known hydrothermal field discovered along the Reykjanes Ridge. The two central areas are located in a region of increasing magma supply. Finally, the southernmost area is underlined by the only magma body ever detected seismically below the Reykjanes Ridge. The analysis combines 15 m resolution ship-based bathymetry, ground-truthing from ROV dives and geochemical analysis of glass samples to look at variations of magma composition, fault density, seamount density and morphology along the ridge axis. Two major parameters influence the distribution and geometry of faults and seamounts: the distance from the hotspot and the accretion state of individual AVR (i.e., magmatic extension vs. tectonic extension). Fracture geometry is highly influenced by the depth of the brittle-ductile boundary that deepens with distance from the plume center, while fault density at the axis reflects different development stages of individual AVR. Seamount morphologies may also reflect individual AVR development, but we also show morphological variation with distance from the hotspot, correlated with the average variation in lava composition and mantle temperature.
Overturning Circulation and mesoscale eddies in the first GO-SHIP section at 34.5ºS across the South Atlantic during January 2017
Authors: Manta Gaston , Speich Sabrina , Karstensen Johannes
Published: March 2020

The variability of the Atlantic Meridional Overturning Circulation (AMOC) is known to have considerable impacts on the global climate system. In particular, the South Atlantic is thought to control the stability of the AMOC. That’s why significant resources have been invested in measuring the AMOC in the South Atlantic since 2009 mainly through mooring deployments accompanied by yearly cruise campaigns in the eastern and western boundaries. In January 2017, the RV Maria S. Merian conducted the first hydrographic (GO-SHIP) transect along the SAMOC-SAMBA line located at 34.5°S in the South Atlantic. In this study, we present analyses of the data obtained during the cruise. Volume and heat transports were calculated using the slow varying geostrophic density field and Ekman transport from daily satellite wind stress data. The general structure of these transports is in close agreement with other estimations at near latitudes. Two defined overturning cells are distinguished with differences in the abyssal circulation between the west and east. While the west shows Antarctic Bottom Waters flowing northward (ɣ > 28.27 kg.m-3) and Lower Circumpolar Deep Waters (LCDW, 28.10 kg.m-3 <  ɣ < 28.27 kg.m-3) above flowing southward, only LCDW are found in the east, flowing northward and southward from 6°E, respectively. The section presented a positive mass imbalance. By assuming the latter to be the barotropic transport component we equally distributed it along the vertical in order to satisfy a net-zero transport. The overturning maximum is located at 1250 meters deep and is 18 Sv with net northward heat transport. Moreover, by using the Laxenaire et al., (2018) eddy detection method, we identified the various mesoscale eddies crossed during the cruise. This analysis provided evidence of the presence of 13 cyclonic and 12 anticyclonic eddies. Among the anticyclonic eddies, three were identified as Agulhas rings. One of these eddies was located close to the Brazilian slope and was more than 5 years old since its first detection. During the cruise, a particularly intense cyclonic eddy was crossed near the African coast. The upper layer velocity within the eddies exceeded 1 m.s-1, with an asymmetric stronger northward flow. Although mesoscale eddies dominate the upper 1000 meters circulation, no significant differences were found in the overturning circulation when replacing the upper 1200 meters layer of 34.5°S observed section with a climatology generated with the ARGO profiles located outside eddies.