bluuebunny/crossref_metadata_2025 huggingface dataset:
Water ages at the soil root interface and beyond
Authors: Seeger Stefan , Weiler Markus
Published: March 2022

At the catchment scale, incoming precipitation is typically partitioned into runoff and evapotranspiration. Most transit time modeling approaches focus on the runoff part of the water balance and are consequently evaluated with respect to water ages in streamflow. Nevertheless, most modeling approaches also include a more or less detailed representation of evapotranspiration. In order to evaluate whether a modeling approach appropriately captures evapotranspiration and its water ages, it is important to understand what processes are required to be considered in the models. While evaporation from the soil and canopy surfaces is relatively easy to observe, transpiration involves root water uptake from a range of depths below the soil surface and water transport within plants. In addition, experimental data to evaluate transit time models are sampled in different organs and locations of plants.

We will present the results of studies dealing with the transit times of root water uptake (between precipitation and water uptake) and with transit times internally in trees (between water uptake at the root tips and transpiration at the leaves) in temperate forests. A novel in-situ measurement technique enabled us to measure stable water isotopes in the soil and within tree stem xylem with unprecedented temporal resolution and thereby enabled us to refine our understanding of plant water uptake and tree internal water transport. Based on our experimental observations, we developed a new approach to model water transport and hence water transit time internally in trees.
Downscaling WGHM-Based Groundwater Storage Data Using Regression Method: A Regional Study over Qazvin Plain, Iran
Authors: Zarghami Dastjerdi Soroush , Sharifi Ehsan , Saghafian Bahram , Güntner Andreas
Published: March 2022

Climate change, urbanization, and growing population have led to the rapid increase in the use of groundwater. Therefore, monitoring the groundwater (GW) changes is essential for water management and decision-makers. Due to frequent lack of reliable and sufficient in-situ information, remote sensing and hydrological models can be counted as the alternative sources for assessing GW storage changes on a regional and global scale. Here, we test such an approach for Qazvin Plain in Iran, one of the regions that recently have been facing severe drought conditions. The main purpose of this study is to downscale GW storage anomaly (GWSA) of the WaterGAP Global Hydrology Model (WGHM) from a coarse (0.5-degree) to a finer spatial resolution (0.1-degree) using fine spatial resolution auxiliary datasets (0.1-degree) such as the evaporation, surface and subsurface runoff, snow depth, volumetric soil water, and soil temperature from the ERA5-Land model and precipitation from integrated multi-satellite retrievals for global precipitation measurement (IMERG). Different regression models were tested for the GWSA downscaling. Moreover, since different water budget components such as precipitation or storage are known to have temporal lead or lag relative to each other, the approach also includes a time shift factor among the components. The most suitable regression model with the highest skill score during the validation test was selected and applied to predict the 0.1-degree GWSA. The downscaled results showed a high agreement with the in-situ groundwater levels for Qazvin Plain in both interannual and monthly scales, with a correlation coefficient of 0.99 and 0.65, respectively. Moreover, the downscaled product clearly proves that the developed downscaling technique is able to learn from high-resolution auxiliary data to capture GWSA features at higher spatial resolution. The major benefit of this method is in utilizing only the auxiliary data that are available with global coverage and free of cost, and that this method does not need in-situ GW records for training. Therefore, the proposed downscaling technique can potentially be applied to a global scale, other geographical regions, or aquifers.

This study has received funding from the European Union’s Horizon 2020 research and innovation programme for G3P (Global Gravity-based Groundwater Product) under grant agreement nº 870353.
A consistent representation of cloud overlap and cloud subgrid vertical heterogeneity
Authors: Lebrun Raphaël , Dufresne Jean-Louis , Villefranque Najda
Published: March 2022

Global or regional atmospheric circulation models often work with horizontal resolutions too large to be able to represent clouds, who have to be parameterized. The way clouds are parameterized and the way they overlap can have a significant impact on their radiative properties. A first objective of this work is to quantify the effect of a vertical description of cloud properties finer than that of current atmospheric models on the calculation of the radiative fluxes at the top of the atmosphere. A second objective is to propose a representation of these subgrid effects that is consistent with the representation of the cloud overlap between layers. For low-level clouds and using LES results as reference, we show the ability of the exponential-random overlap algorithm to represent the vertical distribution of the cloud fraction over a wide range of vertical scales that includes both subgrid scales and overlap between layers, with a constant value of the overlap parameter. Starting from a coarse vertical grid representative of that of atmospheric models, this algorithm is then used to construct the vertical profile of the cloud fraction with a much finer vertical resolution. This reconstruction allows us to test different simplifying hypotheses. We confirm that the frequently used maximum-random overlap leads to a significant error by underestimating the low-level clouds cover with a relative error of about 50%. We suggest some possible representations of subgrid effects and recommend to consider the vertical distribution of the cloud fraction seen from above, which depends on the volume cloud fraction but also on the cloud overlap and the subgrid vertical heterogeneity, when developing or evaluating cloud properties.
The importance of the ecosystem in marine mercury modelling
Authors: Amptmeijer David , Bieser Johannes
Published: March 2022

Mercury is a pollutant of global concern due to its ability for long-range atmospheric transport, combined with its capability to be methylated into the neurotoxin methylmercury in the marine environment. The consumption of methylmercury in seafood is the primary hazard of mercury to humans, but most mercury emissions are in the form of atmospheric inorganic mercury. The link between inorganic atmospheric mercury and organic mercury in biota is poorly understood.  Here we present our newly developed mercury bioaccumulation model for the North and Baltic Sea based on a fully resolved biogeochemical hydrodynamic model. The modelled bioaccumulation falls well in the range of observations and works by combining a new bioaccumulation model combined with the MERCY Hg speciation model and the ECOSMO ecosystem model. In phytoplankton, bioaccumulated mercury is mostly inorganic. In zooplankton inorganic and organic mercury is roughly equal and it originates in similar amounts from direct uptake from the water column and dietary interactions. In planktivorous fish organic mercury originating from trophic interactions is by far the dominant contaminant, interestingly omnivorous have a higher fraction (~20%) of methylmercury from passive uptake than planktivorous fish, this likely due to the longevity (10~15 years) of these high trophic predatorial fish. Notable interactions between bioaccumulation and Hg speciation in the model are that the cyanobacterial uptake of Hg2+ and MMHg on the shallow sea surface layer decreased mercury release into the atmosphere and lead to a higher buildup of both organic and inorganic mercury throughout the water column, additionally, POC is a major factor transporting Hg to deep anoxic bottom water increasing the amount of methylmercury. Our results indicate that the ecosystem plays an essential role in marine Hg cycling and should not be carelessly ignored in models. 
Combined 14C and 230Th/U dating of fine-grained cryogenic cave carbonates from a permafrost cave in Greenland
Authors: Donner Anika , Töchterle Paul , Spötl Christoph , Hajdas Irka , Li Xianglei , Edwards R. Lawrence , Moseley Gina E.
Published: March 2022

Cryogenic cave carbonates (CCC) have become a valuable tool for providing evidence for past permafrost presence, particularly in low-elevation mid-latitude temperate locations (e.g. Germany and UK) and high-elevation mid-latitude periglacial environments (e.g. Austria and Spain). This study focuses on CCC from a low-elevation high-latitude site in the continuous permafrost of the high Arctic. Specifically, the fine-grained form of cryogenic cave carbonates (CCCfine), which precipitate from rapidly freezing thin water films on top of cave ice, are investigated from Eqik Qaarusussuaq (cave) in northeast Greenland (80.2°N). Under contemporary conditions, the sampling site in the interior of the cave is dry, cold (-14.7°C) and ice-free, thus water infiltration to facilitate CCCfine formation is not possible.

Previously, 230Th/U dating efforts of CCCfine have suffered from poor age precision due to high detrital Th contamination. Similarly, 14C dating has been hindered by the unknown reservoir effect (dead carbon fraction). To address these dating issues, we applied a multi-method dating approach to produce a unique dataset comprising eleven 14C ages as well as six 230Th/U ages from a single patch of CCCfine. An isochron indicates that the CCCfine formed synchronously and that the cleanest 230Th/U age is representative for the whole patch. The dead carbon fraction is calculated based on this 230Th/U age.

The results of 230Th/U dating (97±34 a BP) agree with the calibrated 14C age range (40-70 a BP (37.9%), 115-139 a BP (28.2%), 226-254 a BP (29.4%)) that the CCCfine from Eqik Qaarusussuaq most likely formed towards the end of the Little Ice Age or shortly after.
Analysis of fluid induced earthquake swarms in Northern Main Ethiopian Rift
Authors: Raggiunti Martina , Keir Derek , Pagli Carolina , Lavayssière Aude
Published: March 2022

An increase of fluid pressure can induce fault slip and therefore lead to the occurrence of earthquakes. The aim of our works is to investigate this phenomenon from a seismic point of view.

We analyzed the EAGLE seismic database, that includes the earthquakes that occurred in the Northern Main Ethiopian Rift (NMER) from October 2001 to February 2003, with the aim of achieving accurate earthquake locations that show subsurface fault structure and temporal behavior. The earthquakes in the database were relocated with a number different methods including double difference relative relocation following waveform cross correlation. We focus on the Fentale-Dofan magmatic segment, an area involved in the active rifting process with a widespread seismicity and with the presence of surface hydrothermal deposits that suggest ongoing hydrothermal activity. The earthquakes were first relocated with NonLinLoc using a non-linear method and the velocity model from controlled source seismology. The events relocated with NonLinLoc was divided in four distinct clusters, with three clusters in the rift and one cluster on the western border fault. Each cluster was then relocate separately with HypoDD double-difference location algorithm, including implementation of waveform cross correlation. From the earthquake magnitudes, b-values and seismic moment were also computed. Seismic data was interpreted with hydrothermal surface data obtained from automated remote mapping from Landasat 8 images.

The analysis of the temporal-spatial distribution of earthquakes shows that some of the clusters are strongly concentrated in time and in space, and therefore swarm-like. These swarms are characterized by events with similar waveforms. There is direct correlation between the increase of seismic rate in the cluster and the presence of families of similar earthquakes. The values found for the seismic moment suggest that the events are originated from activation of rift related structures. This is supported by the N to NE elongation strike of seismic clusters highlighted by the HypoDD location, in accordance with the tectonic setting of the area. The events are mostly localized in the top 15 km of the crust. The b-values calculated for the clusters are smaller than 1, with the exception for the cluster localized near Dofan volcanic complex. The hydrothermal deposits mapped by us are mainly focused in two areas: on the western side of Dofan volcanic complex, in an area intense faulted by NNE-SSW faults; and around the Fentale volcano with a circular pattern on southern side of volcanic edifice.

The no clear correlation between seismicity and mapped hydrothermal deposits suggesting that seismicity is not driven by shallow hydrothermal fluid flow. It is possible to conclude that these earthquakes have a component fluid induced, but the origin of these fluids are deeper than the fluids that feed the hydrothermal systems.
Use of stable isotope signals from tree rings as proxy for tracing the combined effects of climate change and hydropower on glacier-derived water resources in the Turtmänna river catchment, Switzerland
Authors: Islam Nazimul , Vennemann Torsten , Lane Stuart N.
Published: March 2022

Stable isotope analyses (δ18O, δ2H) combined with the tree-ring dating have enormous potential for tracing freshwater resource availability under changing climate and in the context of the impacts of other human activities. This study focusses on the isotopic composition of tree-rings in combination with an anatomical analysis of the European Larch (Larix Decidua) species from different upstream and downstream sites along the Turtmänna river in south-western Switzerland. The results show distinctive patterns of year-to-year tree-ring growth from their constructed chronology dated back to 1851 (i.e. a 170-year record). A trend of a decreasing growth was noted over the last two decades. Decreasing growth was correlated (r = 0.50) with a decrease in precipitation and an increase in temperature (r = 0.30) during the growing season (between June and October) of previous and current years. The isotopic analysis shows a depletion in 18O in the trees fed by glacial meltwater close to the river as compared to the trees fed by precipitation distal to the river. Given the changes in climate, trees closer to the river are becoming more dependent on river-derived water, which in turn is sourced from melting glaciers. This hence has important consequences for the hydropower generation and water availability.
Characterization of the Elmshorn salt diapir caprock by SH-wave reflection seismic and Full Waveform Inversion
Authors: Mecking Rebekka , Polom Ulrich , Omlin Andreas , Leineweber Philipp
Published: March 2022

Both sudden and continuous subsidence of the earth’s surface pose a geohazard to the population and infrastructure, especially in urban areas. In Northern Germany, sinkholes occur often at salt dome highs, where dissolution affects the caprock, creating mass deficits in the shallow subsurface. Gravitationally driven subsidence of the overburden subsequently leads to both slow and sudden deformations of the surface.

The city of Elmshorn, situated partly on the top of a shallow salt dome structure of nearly 30-40 m below surface, has to deal with such surface deformations which have been the motivation of several investigations in recent decades. Existing geologic data based on drillings has recently been extended by a shear wave seismic 2D profile grid, to support mapping of the spatial course of the salt structures and overlying sediments in high resolution, and to identify areas prone to subrosion more precisely. The seismic profiles were acquired using an Elvis shear wave vibrator (source signal: 20-160 Hz sweep) and a land streamer attached with 10 Hz horizontal geophones in 1 m spacing. High-resolution stacked sections of 0.5 m CMP spacing were generated using shot spacing of 2-4 m. The profile grid shows that the shear wave reflection methodology is suitable to image the heterogeneous caprock surface and the fine structure of the overlaying Quaternary sediments. Strong topographic variations in the caprock surface and strongly heterogeneous lithology of both caprock and overlying sediments occur over short lateral distances less than 100 m, reinforcing the requirements for a close-meshed profile grid. Different caprock lithologies can be distinguished by changes in reflectivity and wavelength. Further, derived physical parameters based on full waveform inversions enable the characterization of the caprock surface and the integrity of the overlying sediments to estimate areas affected by subrosion.

The results highlight the structural information capabilities of the shear wave reflection method for the investigation of subrosion-prone areas as well as the further potential of the methodology to improve the knowledge of subrosion process sequences.
Seismic Attenuation of India, Himalaya and Tibet using Lg-coda waves
Authors: Chaudhuri Dibyajyoti , Ghosh Ayon , Sharma Shubham , Mitra Supriyo
Published: March 2022

We present maps to show the lateral variation of Lg coda attenuation at 1-Hz across India, Himalaya and Tibet. We use vertical component waveforms from regional earthquakes (epicentral distance<3500 km and Mw>5) recorded by the IISER-K seismological network, ones operated by the Indian Meteorological Department, and data acquired from the IRIS-DMC. Lg-coda waves are modeled as single back-scattered energy, sampling an ellipsoidal volume. The attenuation of Lg-coda is quantified using the quality factor (Q), which is frequency dependent. We use the stacked spectral ratio (SSR) method to calculate the single-trace Lg-coda Q at 1 Hz (Qo) and its frequency dependence (η). A moving-window stack of scaled-logarithmic ratios of spectral amplitudes, for window length of 25.6 s and different central lapse time, is computed for each frequency. Through a linear regression of log (stacked spectral ratio) and log (frequency), using least-squares fitting, we obtain (1-η) and log(Qo), respectively. Lg-coda is selected in a frequency range of 0.2-5 Hz, with coda window starting at 3.15 km/s. Our total coda window lengths vary between 140 s to 780 s. Our preliminary results show low Q values (~200-400) in the Eastern and Western Himalaya - possibly because of scattering of seismic energy from structural heterogeneities. Most of the Indian Shield and the intraplate regions of Shillong Plateau and Brahmaputra valley are characterized by intermediate to high Q values (~600-800), indicating fairly efficient propagation of seismic energy. Intermediate values of Q (~400-500) occur in the Indo-Burman Ranges which may be due to the cold elastic subducting oceanic lithosphere. Patches of low Q in the Tibetan Plateau (~200) are possibly the result of high temperatures and partial melts present in the crust. Our results show how the nature of the Indian Plate changes as we go from an active continent-continent collision zone in the north to eastward subduction of transitional material at the Indo-Burma ranges. Our plots of Qo and η as a function of epicentral distance, coda length and magnitude show no systematic variations.
Hydroclimatic extremes regulation by mangroves in a highly vulnerable small Caribbean Island
Authors: Quesada Benjamin , Esteban Cantillo Oscar Julian , Clerici Nicola
Published: March 2022

The archipelago of San Andrés, Providencia and Santa Catalina (SAI), southwestern Caribbean islands (Colombia), declared as a Biosphere Reserve by the UNESCO, is highly vulnerable to tropical storms, meteorological tides, coastal flooding and the effects of sea level rise, which are substantially increasing in a context of climate change. In 2020, for the first time in the Colombian history, a hurricane reached category 5 on its territory, destroying the island of Providencia and damaging San Andrés Island. However, historical and future hydroclimatic events trends along with potential mitigation effects of nature-based solutions with mangroves are still very little known and studied in this part of the Caribbean Sea.

Our study analyzes historical (1960s-2020) and future (2050, across low and high mitigation IPCC scenarios) trends in duration, frequency and intensity of extreme rainfall, wind, floods, hurricanes and tropical storms, and discusses their relationship with the regulation ecosystem services in terms of regulation of erosion, flood control and protection against storms, provided by the SAI mangrove forest ecosystems. Using the InVEST Coastal Vulnerability model with new in-situ data for this specific region, we estimate the vulnerability of the Archipelago (in terms of affected inhabitants, damaged houses, loss of property value) to extreme climate without, with current and with maximal mangrove area.

Our work highlights the urgent need to restore and expand the mangrove forest areas in the Archipelago as a measure of both mitigation and adaptation to climate change and extreme weather events. Investments in reducing the vulnerability of the island's inhabitants to the harmful effects of climate change must combine several strategies (climate mitigation, nature-based solutions, waste management, territorial planning, etc.) to reduce environmental damage, economic and social aspects of one of the largest marine protected areas on Earth.
Long-term variations and trends in the E and sporadic E layer over Juliusruh (54° N), Europe
Authors: Sivakandan Mani , Mielich Jens , Renkwitz Toralf , Chau Jorge  L.
Published: March 2022

Sporadic E (Es) is a thin layer of metallic ion plasma that forms in the E region of the Earth’s ionosphere, mostly between 90 and 125 km. It can affect the radio frequencies in the HF range of up to 30 MHz. In the mid-latitudes, the wind shear mechanism causes the formation of the Es layers. In general, solar forcing primarily controls changes in the E layer. On the other hand, the formation of the mid-latitude Es layer is driven by the wind shear associated with lower atmosphere originated wave activities. Since the formation of the Es layer is caused by the lower atmospheric forcing, it can be used as a tracer to estimate the lower atmospheric impact on the upper mesosphere and lower thermosphere (UMLT). Therefore, the study of the long-term changes and trends (if any) in the E and Es layers will throw some light on the effect of the lower atmosphere and solar forcing on the UMLT region.

In the present study, we investigate the long-term variation and trends in the E region, using sixty-three years of continuous ionosonde observations over Juliusruh (54.6° N 13.4° E), Europe. Before the trend analysis, predominant long-term variations are estimated using the Lomb-Scargle periodogram analysis. We found that the annual and solar cycle oscillations are strongly present in both foE and foEs. In addition, a weak semi-annual oscillation is also noted in the foE.  Furthermore, the model time series data of foE and foEs is created using the period and amplitude of the predominant oscillations. Then, the residual value of foE and foEs is calculated by subtracting the model values from the observation. By using the least square fit analysis, the trend is estimated. Interestingly, weak negative trends in the foE and foEs are found. The plausible causative mechanism for the observed trends will be detailed in the presentation.
The variations of temperature extremes over the wintertime Tibetan Plateau from 1979 to 2018
Authors: Tian Yinglin , Zhong Deyu
Published: March 2022

The Tibetan Plateau (TP), known as the “World Roof”, has significant influences on hydrological and atmospheric circulation at both regional and global scales. As a result, an adequate understanding of TP climate change is of great importance. In this study, the temporospatial variations of temperature extremes over the TP are investigated based on the station and gridded data provided by China Meteorological Administration (CMA) and the Mann-Kendall test. In addition, the typical large-scale circulations along with the temperature extremes are analyzed using the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis data. It is found that while the frequency of the temperature extremes is observed to have gone through significant variations from 1979 to 2018, the intensity of the temperature extremes has no significant change. On the one hand, the frequency of the warm days and nights is getting higher over the southeastern part and northwestern TP; on the other hand, most area of the eastern TP has witnessed a significant decreasing trend in the frequency of cold days and nights, together suggesting a warming TP. Moreover, the distribution of the long-term changes in the warm days and the cold nights resemble those of the multi-year tendencies of the maximum and minimum temperature. Furthermore, both warm days and nights occur with a significant anti-cyclone over the TP for continuous days, which might allow for more solar radiation arriving at the surface and also favors more adiabatic heating along with the sinking movement of the air parcels. Our results imply a possible linkage between the long-term climate change in the TP, the temperature extremes over the TP, and the large-scale circulations.
How do we ensure that the humanitarian use of forecasts is robust?
Authors: Stephens Liz , Mitheu Faith , Speight Linda , Hossain Sazzad , Cloke Hannah , Giodini Stefania
Published: March 2022

Forecast-based action within the humanitarian community supports at-risk communities when a forecast indicates a potentially imminent disaster. Within the Red Cross Red Crescent Movement the development of an Early Action Protocol enables access to pre-agreed funds and avoids indecision when faced with an uncertain forecast. To ensure value for money, this protocol must demonstrate that the forecast is good enough for the decisions being made. But how can we be confident that forecasts are good enough if we don’t have any observations? How do we evaluate an impact-based forecast? And how do we communicate these limitations to all stakeholders? In this talk I will discuss some of the challenges we have faced, and some solutions.
Effects of Spatial Grid Resolution on the Statistical Power of Testing Earthquake Forecast Models
Authors: Khawaja Muhammad Asim , Hainzl Sebastian , Iturrieta Pablo , Schorlemmer Danijel
Published: March 2022

The Collaboratory for the Study of Earthquake Predictability (CSEP) is an international effort to independently evaluate earthquake forecasting models and to provide the cyber-infrastructure together with a suite of testing methods. For global forecasts, CSEP defines a grid-based format to describe the expected rate of earthquakes, which is composed of 6.48 million cells for a 0.1º spacing. The spatial performance of the forecast is tested using the Spatial test (S-test), based on joint log-likelihood evaluations. The high-resolution grid combined with sparse and inhomogeneous earthquake distributions leads to many empty cells that may never experience an earthquake, biasing the S-test results. To explore this issue, we conducted a global earthquake forecast experiment. We tested a spatially uniform forecast model, which is non-informative and should be rejected by the S-test. However, it is not rejected by the S-test when the spatial resolution is high enough to allocate each observed earthquake in individual cells, thus raising questions about the test statistical power.

The number of observed earthquakes used to evaluate global forecasts is usually only a few hundred, in contrast to the millions of spatial cells. Our analysis shows that for such disparity, the statistical power of tests for single-resolution grids also depends on the number of earthquakes available to evaluate a model. With few earthquakes, the S-test does not allow powerful testing.

We propose to use a multi-resolution grid to generate and test earthquake forecast models, in which the resolution can be set freely based on available data, e.g., by the number of earthquakes per cell. Data-driven multi-resolution grids demonstrate the ability to reject the uniform forecast, contrary to a high-resolution grid. Furthermore, multi-resolution grids offer powerful testing with as minimum as four earthquakes available in the test catalog. Therefore, we propose to use multi-resolution grids in future CSEP global forecast experiments and to further study its application in regional and local experiments, where such sparsity of observations is present.
The Soi crater region on Titan: Detailed geomorphological and compositional maps
Authors: Solomonidou Anezina , Schoenfeld Ashley , Lopes Rosaly , Malaska Michael , Coustenis Athena , Schmitt Bernard
Published: March 2022

The Soi crater region, an extensive region covering almost 10% of Titan’s surface, has the Soi crater in its middle, which is a relatively well-preserved crater on Titan.  This region includes the boundaries between the equatorial regions of Titan and the mid-latitudes, and extends into the high northern latitudes (above 50o). All these three Titan latitudes are dominated by different types of geomorphological units, such as dunes, mountains, and lakes, and are governed by different geological processes (such as lacustrine, aeolian and fluvial). An additional important and unique characteristic of the Soi crater region is that it includes 59 empty lakes, and the extent of these features reaches as far south as 40oN. We mapped this region at 1:800,000 scale and produced the first detailed geomorphological map of the region using the same methodology as presented by [1;2] and Schoenfeld et al. [3]. We included non-SAR (Synthetic Aperture Radar) data such as radiometry, ISS, and VIMS data in order to analyze vast areas not observed by SAR. We performed detailed VIMS analysis of hundreds of distinct regions for all geomorphological units with a radiative transfer technique [4] and a mixing model [5], to infer constraints on the composition. In our results, we introduce new geomorphological units, which were not seen in previous mapping of large Titan regions such as the Afekan and South Belet, and report the extensive presence of the scalloped plains units and their possible origin. A total of 10 craters, including Soi, are identified in this region, which are older than the plains and dune units. The radiative transfer analysis from VIMS showed that the major constituents covering the Soi crater region are compatible with water ice and organic alkane, alkene and alkyl-like stretch materials. We discuss our results in terms of origin and evolution theories.

[1] Malaska, M., et al. (2016), Icarus 270, 130; [2] Malaska, M., et al. (2020), Icarus, 344, 113764. [3] Schoenfeld, A., et al. (2021), Icarus 366, 114516. [4] Solomonidou, A., et al. (2020a), Icarus, 344, 113338; [5] Solomonidou, A., et al. (2020b), A&A 641, A16.

 

 

 
Identification of the main meteorological factors for the trend of reference evapotranspiration in Sicily, Italy
Authors: Aschale Tagele Mossie , Cancelliere Antonino , Peres David , Sciuto Guido
Published: March 2022

Climate change has potential impacts on the hydrological cycle components, especially those strongly related to temperature, such as evapotranspiration. Assessing trends of the reference evapotranspiration (ETo) and of the related climatic factors is essential for improving water resource management especially with reference to watershed  hydrology and agricultural uses. In this research, we aim to analyze the trend of ETo and of its influencing climatic factors.  More specifically, we examine the sensitivity of ETo for different climatic factors and the contribution of climatic factors for the trend of ETo in the study area.  The study considered decadal observations of climatic data from meteorological stations in Sicily, and reference evapotranspiration was estimated through the FAO Penman-Monteith method.  The Mann-Kendall test, with verification of the Trend-free prewhitening (TFPW) method, has been applied for the trend and sensitivity analyses. The Sen’s slope has also been used to examine the magnitude of the trend. Results, relative to a pilot gauging station in Piazza Armerina, indicate that the ETo has decreasing trend only in November with a decrease of 0.790 mm per year. The solar radiation (November and Autumn) and rainfall (Autumn) showed decreasing trends. While other climatic factors (minimum temperature, maximum temperature, mean temperature, wind speed and relative humidity) showed increasing trend both monthly and seasonally in the study area. Furthermore, the sensitive analysis shows that ETo is mostly sensitive to relative humidity and least sensitive to wind speed in the study area. Similarly relative humidity contributes the most to the trend of ETo (44.59% decreasing contribution), while wind speed has the least contribution (0.9% increasing contribution) in the study area.  These results can find application for irrigation scheduling and water related development project in the study area.
QUADICA: A large-sample data set of water quality, discharge and catchment attributes for Germany
Authors: Ebeling Pia , Kumar Rohini , Lutz Stefanie R. , Nguyen Tam , Sarrazin Fanny , Weber Michael , Büttner Olaf , Attinger Sabine , Musolff Andreas
Published: March 2022

Environmental data are critical for understanding and managing ecosystems, including mitigation of degraded water quality. Therefore, we provide the first large-sample water quality data set of riverine water quality combined with water quantity, meteorological and nutrient forcing data, and catchment attributes for Germany in a preprocessed and structured form. The QUADICA data set (water QUAlity, DIscharge and Catchment Attributes for large-sample studies in Germany) covers 1386 German and transboundary catchments with a large range of hydroclimatic, topographic, geologic, land use and anthropogenic settings. The data set comprises time series of riverine macronutrient concentrations (species of nitrogen, phosphorus and organic carbon), discharge, meteorological and diffuse nitrogen forcing data (nitrogen surplus, atmospheric deposition and fixation). The time series are generally aggregated to an annual basis; however, for 140 stations with long-term water quality and quantity data (more than 20 years), we additionally provide monthly median discharge and nutrient concentrations, flow-normalized concentrations and corresponding mean fluxes as outputs from weighted regressions on time, discharge, and season (WRTDS). The catchment attributes include catchment nutrient inputs from point and diffuse sources and characteristics from topography, hydroclimate, land cover, lithology and soils. QUADICA is a comprehensive, freely available, ready-to-use data set that facilitates large-sample data-driven water quality assessments at catchment scale as well as mechanistic modeling studies. We hope to stimulate the hydrological and water quality communities to provide similar data sets to create novel research opportunities, increase our understanding of catchment functioning, and ultimately improve water quality management.
Fifteen-years of Tropopause Altitude monitoring by GNSS Radio Occultation Measurements
Authors: Vespe Francesco , Andrisani Andrea
Published: March 2022

Tropopause altitude variability can be considered one of the most effective indicator  of climate changes.  In particular with warming/cooling of the troposphere, it works as  the mercury vertical column in an old analogic thermometers. Besides, tropopause location affects the stratosphere–troposphere energy and matter exchange,through  the overshooting of  the water vapor from the troposphere to the  stratosphere occurring in particular  at tropical latitudes. So, the monitoring of tropopause altitudes and determination of possible local/global trends, are extremely important for climate investigations.

In this work we plan to estimate and monitor tropopause altitudes on global scale for a period ranging from 2007 up to 2021, by processing millions of  GNSS Radio Occultation (RO) observations stacked thanks to  COSMIC (I & 2) FORMOSAT missions. An analysis over such time scale could be very helpful to understand the long periodic climate trends of Earth. For this task we apply    four different tropopause altitude definitions: the Lapse Rate Tropopause (LRT), the Cold Point Tropopause (CPT), a weak form of LRT as defined in (Andrisani & Vespe, 2021), and the tropopause altitude defined by (Vespe at al., 2017), based on the detections of bumps in bending angle (BA) profiles. This last definition could be more easily applied  than the LRT or the CPT , because  BA are raw data of level 1 provided by RO, while  temperature profiles are data of level 3  and   require additional assumptions and  , in somehow, a  more problematic modeling.
Variably depleted mantle in the source of Azores lavas
Authors: Béguelin Paul , Stracke Andreas , Genske Felix , Bizimis Michael , Beier Christoph , Willig Michael
Published: March 2022

The Azores Plateau in the North Atlantic is a classic example of near-ridge oceanic plateau (600 km) associated with the upwelling of the Azores mantle plume. The radiogenic isotope signatures of Azores lavas show systematic inter-island variations, which are often interpreted in terms of sampling several distinct, chemically enriched reservoirs from the Azores plume [1].

Here we discuss new radiogenic cerium isotope data on Azores lavas in the context of recent isotope data on olivine-hosted melt inclusions [2]. Olivine-hosted melt inclusions have very high neodymium isotope ratios (up to εNd = 18.1), suggesting that variably depleted mantle is the dominant component of the Azores mantle source [2]. Radiogenic Ce isotopes reflect the time-integrated La/Ce ratio of the mantle source. La/Ce approaches zero values in incompatible element depleted mantle, while the Sm/Nd and Lu/Hf ratios retain higher, more variable values. Melts from variably depleted mantle therefore develop distinct signatures in Ce–Nd–Hf space [3].

The new Ce isotope values for 36 whole-rock lava samples covering the whole Azores Plateau reveal a number of parallel, vertically stacked trends in Ce–Nd and Ce–Hf isotope space, pointing to variably incompatible depleted end-members, that are not discernible in Sr–Nd–Pb–Hf isotope space. The observed isotope trends in Ce–Nd–Hf space are readily explained by variable contribution of melts from volumetrically dominant, but variably depleted mantle and similar, but inherently heterogeneous enriched local plume components. Hence, although not directly reflected in the erupted basalts on a whole-rock scale [1, 2], variable contribution of melts from a variably, in part highly depleted mantle control the isotope composition of Azores lavas.

These results indicate the North Atlantic mantle below the Azores is variably depleted and contains highly depleted domains. The lavas closest to the proposed plume center [4] do not correspond to either extreme in terms of mantle depletion, suggesting mantle depletion in Azores is inherently complex and not a simple mixing product between plume and ridge mantle.

 

[1] Béguelin et al. (2017) Geochimica et Cosmochimica Acta, 218, 132-152.

[2] Stracke et al. (2019) Nature Geoscience, 12(10), 851-855.

[3] Willig et al. (2020) Geochimica et Cosmochimica Acta, 272, 36-53.

[4] Bourdon et al. (2005) Earth and Planetary Science Letters, 239, 42-56.
Palaeobathymetric evolution of the Nova Scotia rifted margin during the Central Atlantic Ocean opening
Authors: Tugend Julie , Kusznir Nick , Mohn Geoffroy , Deptuck Mark , Kendell Kris , Keppie Fraser , Morrison Natasha , Dmytriw Russell
Published: March 2022

The palaeobathymetric evolution of rifted margins during continental breakup is complex. We investigate the subsidence of Late Triassic to Early Jurassic evaporitic sequences in the proximal and distal parts of the Scotian margin that formed during the opening of the Central Atlantic Ocean.

We use a 3D flexural backstripping technique, which incorporates decompaction and post-breakup reverse thermal subsidence modelling applied to key stratigraphic intervals through the Jurassic down to the Late Triassic base salt. The isostatic evolution of rifted margins depends on crustal thinning, lithosphere thermal perturbation and melt production during rifting and breakup. Quantitative analysis of seismic reflection and gravity anomaly data together with subsidence analysis have also been used to determine crustal thickness variations and ocean–continent transition structure, and to constrain the along strike variability in breakup related magmatism and crustal composition.

Reverse post-breakup subsidence modelling to the Late Triassic base salt restores this horizon at breakup time to near sea level in the proximal domains of the Scotian margin where the continental crust was only slightly thinned during rifting. In contrast, predicted palaeobathymetry of the base salt surface restored to breakup time is greater than 2 to 3 km in the distal parts of the margin where the continental crust was highly thinned (<10km) close to the ocean-continent-transition. One possible interpretation of this is that while the proximal salt underwent post-rift thermal subsidence only, the distal salt was deposited during the latest stage of rifting focused along the distal domains of the Scotian margin, where it underwent additional tectonic subsidence from crustal thinning. This observed difference between the subsidence of proximal and distal salt has been observed elsewhere on the South Atlantic margins (e.g., the Angolan Kwanza margin) and illustrates the complexity of the subsidence and palaeobathymetric evolution of distal rifted margins during breakup.

The deposition of Triassic evaporites occurred before and after the emplacement of the Central Atlantic Magmatic Province (CAMP). The impact of the CAMP on rifting, crustal structure and palaeobathymetric evolution of the Nova Scotia remains to be determined. We do not exclude an additional positive dynamic topography effect at breakup time related to the CAMP magmatic event.
Approaches for Enabling Interoperable Enterprise Data Search: Insights from NASA’s Science Mission Directorate (SMD) Catalog Project
Authors: Bugbee Kaylin , Ramachandran Rahul , Acharya Ashish , Ton That Dai-Hai , Hedman John , Bitner David , Eleish Ahmed , Driessnack Charles , Adams Wesley , Foshee Emily
Published: March 2022

NASA’s Science Mission Directorate (SMD) is working to build an open-source science infrastructure to enable open, collaborative and interdisciplinary science. One key component in the open-source science infrastructure is the SMD data catalog project. The SMD data catalog project is building an integrated SMD enterprise search capability to enable discovery of open data across SMD’s five divisions, including Astrophysics, Biological and Physical Sciences, Earth Science, Heliophysics and Planetary Science. In order to efficiently integrate heterogeneous data types across the SMD enterprise, the SMD data catalog project considered three approaches for implementation including semantic mapping, graph data stores and Cognitive Search capabilities. In this presentation, we will describe the SMD data catalog project business case, the three identified technical approaches and our assessment of those approaches. We will also provide a summary of the overall technical assessment process so that it may inform other agencies and organizations who may be implementing similar initiatives. 
Using remote sensing and GIS to project climate risk for asset management users
Authors: Brennan James , Burke Claire , Ramsamy Laura , Mitchell Hamish , Kluza Kamil
Published: March 2022

At Climate X we are producing risk estimates for the UK to help businesses and communities mitigate and adapt for climate change related losses. Climate X provides risk scores and expected financial losses from a plethora of hazards including flooding, subsidence, landslides, drought, fire and extreme heat. To do this at the scales we need, Earth Observation (EO) and other geospatial data sets play a crucial role in both physical modelling and risk estimation. Generating rich geospatial datasets to sit as the bedrock of risk models requires intelligent use of multiple data sources, involving the fusion of EO data from synthetic aperture radar, lidar and optical instruments and across processing levels from L1 to L3. This talk will cover the generation and use of these datasets that drive physical risk models (flooding) as well as ML enabled models (Landslides and subsidence).
Response of water fluxes and biomass production to climate change in permanent grassland soil ecosystems
Authors: Groh Jannis , Forstner Veronika , Vremec Matevz , Herndl Markus , Vereecken Harry , Gerke Horst H. , Birk Steffen , Pütz Thomas
Published: March 2022

The effects of climate change on ecosystem productivity and water fluxes have been studied in various types of experiments, but it is still largely unknown whether and how the experimental approach itself affects the results of such studies. We use data from high precision weighable lysimeter from two contrasting experimental approaches to determine and compare the responses of water fluxes and aboveground biomass to climate change in low mountain range permanent grasslands. The first approach is based on a controlled increase in atmospheric CO2 concentration and surface temperature (type manipulative). Space-for-time substitution along a gradient of climate conditions was used in a second approach (type: observational). The Budyko framework was used here to determine if the soil ecosystem is energy or water limited.

Under energy-limited conditions and elevated temperature, actual evapotranspiration increased, while seepage, dew, and aboveground biomass decreased. Elevated CO2 mitigated the effects on actual evapotranspiration. Under water-limited conditions, increased temperature decreased actual evapotranspiration, and aboveground biomass correlated negatively with increased drought.

Our results reveals that the responses of soil water fluxes and biomass production of both experimental approaches depend mainly on the status of ecosystems in terms of energy or water limitation. To better understand ecosystem responses to climate change and identify potential tipping points, climate change experiments must include sufficiently extreme boundary conditions so that responses to single and multiple forcing factors can be comprehensively studied. Manipulative and observational climate change experiments complement each other well in this regard, and thus the approaches should be combined in future research on climate change impacts on grasslands.