julilili42/papers huggingface dataset:
Fingerprint of volcanic forcing on the ENSO&#8211;Indian monsoon coupling
2021-03-04

&amp;lt;p&amp;gt;The coupling between the El Ni&amp;amp;#241;o&amp;amp;#8211;Southern Oscillation (ENSO) and Indian Monsoon (IM) plays a significant role in the summer rainfall over the Indian subcontinent. In this study, we provide insights into the IM variability with regard to the degree of ENSO variability and radiative forcing from large volcanic eruptions (LVEs). Volcanic dust and gas injected into the stratosphere during major eruptions influence the&amp;amp;#160;ENSO from seasonal to interannual timescales. However, the effects of LVEs on the ENSO-IM coupling remain unclear. The relationship between ENSO and IM systems in the context of LVEs is examined using a panoply of datasets and advanced statistical analysis techniques in this study. We find that there is a significant enhancement of the phase-synchronization between ENSO and IM oscillations due to increase in angular frequency of ENSO in the last millennium. Twin surrogates-based statistical significance testing is also used to affirm this result and similar evidence is found in the combinations of 14 ENSO and 11 IM paleoclimate proxy records in the last millennium. Bayesian probabilities conditioned with and without LVEs show LVEs lead to a strong ENSO-IM phase-coupling, with the probabilities remaining higher till the fourth year from the eruption. A large-ensemble climate model experiment with and without the 1883 Krakatoa eruption is conducted using the IITM-ESM, and also with varied volcanic radiative forcing (VRF) depending on the evolved state of ENSO. The simulations show that LVEs force the ENSO-IM systems into a coupled state, and increase (decrease) in the VRF leads to an enhanced (decreased) probability of the phase synchronisation of ENSO-IM systems with a high chance of El Ni&amp;amp;#241;o-IM drought in the year following the LVE. Our results promisingly pave a way not only for improving the seasonal monsoon prediction improvements but also for the regional impact assessment from the proposed geo-engineering activities over the South Asian region.&amp;lt;/p&amp;gt;
A Comparison of Six Transport Models of the MADE-1 Experiment Implemented with Different Types of Hydraulic Data
2021-03-04

&amp;lt;p&amp;gt;Six conceptually different transport models are applied to the MADE-1 field tracer experiement as a first major attempt for model comparison. The objective was to show that complex mass distributions in heterogeneous aquifers can be predicted without calibration of transport parameters - solely making use of structural and flow data.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The models differ in their conceptualization of the heterogeneous aquifer structure, computational complexity, and use of conductivity data obtained from various observation methods (Direct Push Injection Logging - DPIL, Grain Size Analysis, Pumping Tests and Flowmeter). They agree in the underlying physical transport processes, none of them considering mass transfer. Predictive capability is assessed by comparing results to observed longitudinal mass distributions of the MADE-1 experiment. We deal with data uncertainty indicated by decreasing rates of recovered mass by focusing the comparison on measures, such as peak location, position and shape of bulk mass and leading tail, and we do not normalize observation data.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Comparison of models reveals that the predictions of the solute plume agree reasonably well with observations if the models are underlined by a few parameters of close values: mean velocity, a parameter reflecting log-conductivity variability and a horizontal length scale related to conductivity spatial correlation. The robustness of the results implies that conservative transport models with appropriate conductivity upscaling strategies of various observation data provide reasonable predictions of plumes longitudinal mass distribution as long as key features are taken into account.&amp;lt;/p&amp;gt;
Partitioning of trace metals in cave (and cave-analogue) carbonate precipitates &#8211; towards a quantitative hydrological proxy in stalagmites&#160;
2021-03-04

&amp;lt;p&amp;gt;Speleothems (secondary cave carbonate deposits) are particularly valuable for studying past climates over a range of temporal and spatial scales, owing to their continuous growth and exceptional viability for radiometric dating. However, the interpretation of many speleothem-based palaeoenvironmental proxies (e.g., stable isotope ratios &amp;amp;#948;&amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;O and &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C) in terms of particular environmental or climatic controls remains challenging, and is typically limited to qualitative reconstructions of past environmental conditions and dynamics.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;In this study, we develop a novel class of quantitative hydrological proxies by exploring the kinetic behaviour of a suite of first-row transition metals (e.g., Ni, Cu, Co) found in stalagmites. The transport of these elements from the surface to the cave is strongly controlled by the binding to natural organic matter (NOM) present in infiltrating waters. The rate of dissociation of such metal-NOM complexes at the dripwater-stalagmite interface has recently been suggested to determine the availability of these elements for the incorporation into precipitates (Hartland &amp;amp; Zitoun, 2018). The link between NOM-complex dissociation and metal availability for deposition presents an opportunity to quantitatively relate respective carbonate metal concentrations to the time available for complexes to disintegrate and release metals within the thin water films on stalagmite surfaces.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;We present preliminary analyses assessing trace metal kinetics and partitioning in monitored natural cave settings, as well as cave-analogue experimental setups. Our findings demonstrate the contrasting controls on the concentrations of different elements in speleothems, and highlight the potential for kinetically-limited elements in stalagmites to enable quantitative estimations of past hydrological variability.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;lt;strong&amp;gt;References:&amp;lt;/strong&amp;gt;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Hartland, A., Zitoun, R. (2018) Transition metal availability to speleothems controlled by organic binding ligands. Geochem. Persp. Let. 8, 22&amp;amp;#8211;25.&amp;lt;/p&amp;gt;
Enhancing accuracy and interpretability of machine learning models using super learning and permutation feature importance techniques in digital soil mapping&#160;
2021-03-04

&amp;lt;p&amp;gt;The digital soil mapping (DSM) approach predicts soil characteristics based on the relationship between soil observations and related covariates using machine learning (ML) models. In this research, we applied a wide range of machine learning models (12 base learners) to predict and map soil characteristics. To enhance accuracy and interpretability we combined the base learner predictions using super learning strategy. However, a major problem of using super learning and complex models is that the explicit share of individual covariates persons in the overall result cannot be explicitly quantified. To overcome this restriction and make the super learning models interpretable, we employed model-agnostic interpretation tools, for example, permutation feature importance. Particularly, we integrated the weight assigned to each ML base learner obtained by super learning and the ranked ML base learner&amp;amp;#8217;s covariates obtained by permutation feature importance to explore the contribution of covariates on the final prediction. We tested our super learning and permutation feature importance techniques to predict and mapping physicochemical soil characteristics of Urmia Playa Lake (UPL) sediments in Iran. As expected, our results indicated that super leaning could significantly improve the ML accuracies for predicting soil characteristics of single base learners. In terms of root mean square error, super learning improved over the performance of the linear regression by an average of 45.7%. Furthermore, the permutation feature importance allowed us to interpret our results better and prove the significant contribution of geomorphological features and groundwater data in predicting soil characteristics of UPL sediments.&amp;lt;/p&amp;gt;
Ultrasonic velocity experiments on ice cores to complement fabric measurements
2021-03-04

&amp;lt;p&amp;gt;The ice crystal structure and in particular the crystal orientation fabrics (COF) provide valuable information about the deformation history of ice sheets and glaciers. Therefore, COF analysis has been among the standard measurement techniques for most deep ice core drilling projects in the last three decades. The analysis depends on carefully prepared thin sections of ice that are measured with cross-polarised light microscopy or electron backscattering and diffraction (EBSD). The preparation of thin sections is labour-intensive and therefore only a discrete number of samples along the ice core is usually analysed. Geophysical methods such as ultrasonic sounding along the ice core could be employed to complement the discrete fabric data by providing data to fill the gaps. A suitable method needs to be reasonably fast, ideally non-invasive and provides unambiguous information in combination with the established methods.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;In our study, we demonstrate the feasibility of such ultrasonic experiments applied to an ice core to support the approved cross-polarised light microscopy method. Point-contact transducers transmitted ultrasonic waves into ice core samples from a temperate glacier. X-ray computer tomography measurements provide the required information to consider the effect of a two-phase medium (ice and air bubbles) in a porosity correction of the velocity. We determined the azimuthal variation of the seismic velocity. This variation is a result of seismic anisotropy due to the crystal orientation within the ice core volume. The measurements can be acquired within minutes and do not require an extensive preparation of ice samples.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;In addition, the COF of adjacent ice core samples was measured with cross-polarised light spectroscopy. From this, we derived the elasticity tensor and finally calculated the associated seismic velocities for the same azimuth and inclination angle as for the ultrasonic experiments. We compare these two velocity profiles and discover a significant discrepancy in presence of large ice grains. However, with an increasing number of ice grains both methods provide similar results. Although the ultrasonic measurements reveal some ambiguities, these can be resolved when considering the information derived from the standard analysis.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;We conclude that ultrasonic measurements along the ice core are suitable to support the established COF analysis for sufficiently small grains as found in polar cores. We recommend further exploration of the potential of the presented technique as it provides both the chance to obtain a continuous fabric profile and a direct link to large-scale seismic measurements in the vicinity of ice core drilling sites.&amp;lt;/p&amp;gt;
Sub-decadal scale coupling of the Moroccan Sidi Ali lake core record with historical and meteorological data for the last 120 years
2021-03-04

&amp;lt;p&amp;gt;The Western Mediterranean region including the North African desert margin faces major environmental challenges in the backdrop of global climate change in terms of rising temperatures, a higher recurrence of drought events and a decrease in annual precipitation. As a condition to state further prospects, it is crucial to comprehend past and present hydro-climatic patterns. The Moroccan Middle Atlas is considered a transition zone between Atlantic, Mediterranean and Saharan air masses and is therefore of unprecedented interest in order to comprehend regional climate variability and to assess emerging hydrological, geomorphological and ecological impacts. Despite the growing number of limnological studies from the Middle Atlas, there still is a strong need for coupling palaeolimnological results at the sub-recent time scale with historical cartographic information, meteorological variables and underlying climatic forcing. Lake Sidi Ali (33&amp;amp;#176;03&amp;amp;#8217; N, 5&amp;amp;#176;00&amp;amp;#8217; W, 2080 m a.s.l.) provides a unique archive for understanding environmental changes throughout the 20&amp;lt;sup&amp;gt;th&amp;lt;/sup&amp;gt; century. At least for the past 100 years the lake has experienced a minimum of three significant lake level changes in the order of several meters. We were able to reconstruct and quantify these alternations with the help of historical sources, topographic maps and satellite imagery. In addition, we implemented a multi-proxy analytical approach on a 145-cm long sediment record, including &amp;amp;#948;&amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;O and &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C isotope analysis of ostracod shells and CNS elemental analysis. A reliable age model based on 25 &amp;lt;sup&amp;gt;210&amp;lt;/sup&amp;gt;Pb measurements and one radiocarbon dated cedar needle enables the linkage of sediment geochemical variations to lake level changes based on an instrumental record and historic topographic maps. We use meteorological precipitation and temperature data to evaluate the main drivers controlling these fluctuations. Furthermore, we have indications for a temporal coupling of Atlantic climate patterns (North Atlantic Oscillation, NAO; Atlantic Multidecadal Oscillation, AMO) with Sidi Ali lake level development.&amp;lt;/p&amp;gt;
Interior of an ice stream: 3-D geometry of distorted radar stratigraphy of upstream NEGIS and vicinity.
2021-03-04

&amp;lt;p&amp;gt;The North East Greenland Ice Stream clearly stands out in the surface velocity field of the ice flow of Greenland, with its sharp and narrow shear margins visible in the flow field almost up to the central divide. While the current extent and strength of the streaming can be determined from remotely sensed velocities of the ice surface, it is less known how the ice stream is affecting the deeper layers of ice in its catchment area, and how it may have evolved over time. The deformation of the ice due to streaming can be made visible by mapping the distortion of the isochronous stratigraphy of the ice. This has been done by an airborne radar survey centering on the location of the EGRIP drilling camp, carried out with the ultra wide band &amp;amp;#160;radar system (AWI UWB). The dense grid of profiles arranged mainly perpendicular to the ice flow reveals the imprint that the strong shearing leaves within the layering of the ice. Although the layers are tightly folded and distorted within the shear zones, it is possible to continuously trace reflections within the upper half of the ice column throughout the entire survey area. It can be shown that the intensity of the folding is linked to the strain rate field derived from the surface velocities, and that the deformation history of the ice is preserved in the folded layers, even after it is no longer affected by high strain rates.&amp;amp;#160; The advection patterns of the mapped stratigraphic features reveal how the streaming of the ice and the resulting local changes of surface topography may have affected the inflow into the stream and the position of the shear margins over time.&amp;lt;/p&amp;gt;
Building a coupled data assimilation system for the atmosphere, land-surface and subsurface on the catchment scale
2021-03-04

&amp;lt;p&amp;gt;We present a data assimilation (DA) system for the atmosphere-land-surface-subsurface system on the catchment scale. The Neckar catchment in SW-Germany served as the specific case where the DA in combination with the coupled atmosphere-land surface-subsurface model TSMP was used&amp;lt;!-- This needs further clarification. --&amp;gt;. TSMP couples the atmospheric model COSMO, the land-surface model CLM and the hydrological model ParFlow to the DA framework PDAF. We will discuss how the ensemble system is set up in order to work properly and what issues we faced during our initial testing. For the atmosphere we found that it is important to have a good ensemble of lateral forcings as changing internal parameters for various parametrizations does not introduce sufficient variability on its own due to the rather small size of our domain. For the sub-surface the choice of parameters becomes most important and as such parameter estimation will be a valuable tool for improving DA results significantly. Finally, we are showing some first DA results with our system concerning soil moisture with two different assimilation methods &amp;lt;!-- This should be more precise. What do you exactly mean? Two data assimilation methods? Two different simulation scenarios? --&amp;gt;with a fully coupled model setup. In the first assimilation scenario in-situ soil moisture data measured by cosmic ray probes are assimilated, while in the second assimilation scenario remotely sensed near surface soil moisture is assimilated. The first results are encouraging and we discuss additional planned simulation scenarios with the fully coupled atmosphere-land surface-subsurface modelling system as well as plans to test strongly coupled DA, where measurements are used to update states across compartments, possibly resulting in additional accuracy gain compared to traditional uncoupled DA.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;lt;span&amp;gt;&amp;amp;#160;&amp;lt;/span&amp;gt;&amp;lt;/p&amp;gt;
How to model enhanced firn densification due to strain softening
2021-03-04

&amp;lt;p&amp;gt;Most classical firn densification models merely consider temperature and accumulation rate as variable input parameters. However, in locations with high horizontal strain rates, such as the shear margins of ice streams, a reduced firn thickness can be observed. This is explained by an enhancement of power-law creep due to the effect of strain softening, which is not yet captured by existing firn models. We present a model extension that corrects the densification rate, predicted by any classical, climate-forced firn model, for the effect of strain softening caused by horizontal strain rates. With the presented model firn densities measured along a cross-section of the North-East Greenland ice stream (NEGIS) are reproduced with good agreement, validating the accuracy of the developed model. The results further indicate the general importance of considering strain rates in firn densification modeling and pave the way for the development of a firn model that inherently uses temperature, accumulation rate and horizontal strain rates as forcing parameters.&amp;lt;/p&amp;gt;
Surgical repair of severely incompetent quadricuspid truncal valve
2021-03-04

The surgical management of truncus arteriosus poses a constant challenge for the cardiac team treating the patient. A correct diagnosis, surgical therapy and postoperative management are crucial for the survival of the patient. Almost 30% of the patients show an abnormal number of leaflets in the truncal valve, the majority being quadricuspid valves. Additionally, around 25% of the patients show some degree of truncal valve incompetence. We demonstrate an effective way to reconstruct incompetent, quadricuspid valves with good postoperative outcome.
Estimation of water table, soil states and parameters of integrated subsurface-land surface models by data assimilation
2021-03-04

&amp;lt;p&amp;gt;Estimating states and fluxes of the water cycle with terrestrial system models needs a large amount of input data, including soil and vegetation parameters, resulting in large uncertainties in model predictions. Assimilation of pressure head and/or soil moisture data can better constrain states and parameters of a terrestrial system model. Here we assimilate pressure head data and soil moisture data in a terrestrial system model over the Neckar catchment (13928 km&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;) with a spatial horizontal resolution of 800 m. We use the Terrestrial System Modeling Platform (TSMP), which consists of an atmospheric model component (not used in this work), the Community Land Model version 3.5 (CLM3.5), and the subsurface hydrological model Parflow, coupled by OASIS. TSMP is coupled to the Parallel Data Assimilation Framework (PDAF), which allows the assimilation of land surface and subsurface observations to estimate the model states and parameters. In this work the localized Ensemble Kalman Filter (LEnKF) was used to update hydraulic head, soil moisture and/or saturated hydraulic conductivity by assimilating hydraulic head or in situ soil moisture observations for a period of one year. Ensembles of soil properties, leaf area index and atmospheric forcings were generated. The ensemble of atmospheric forcings considered correlations among four variables, and spatio-temporal correlations of the atmospheric variables using a geostatistical procedure. The characterization of the water table depth and river discharge without data assimilation and for different scenarios of pressure head and soil moisture data assimilation were compared.&amp;lt;/p&amp;gt;
Mesenchymal Stem Cell Therapy for Severe COVID-19 ARDS
2021-03-05

Background: The COVID-19 pandemic reached Germany in spring 2020. No proven treatment for SARS-CoV-2 was available at that time, especially for severe COVID-19-induced ARDS. We determined whether the infusion of mesenchymal stromal cells (MSCs) would help to improve pulmonary function and overall outcome in patients with severe COVID-19 ARDS. We offered MSC infusion as an extended indication to all critically ill COVID-19 patients with a Horovitz index &lt;100. We treated 5 out of 23 patients with severe COVID-19 ARDS with an infusion of MSCs. One million MSCs/kg body weight was infused over 30 minutes, and the process was repeated in 3 patients twice and in 2 patients 3 times. Result: Four out of 5 MSC-treated patients compared to 50% of control patients (9 out of 18) received ECMO support (80%). The MSC group showed a higher Murray score on admission than control patients, reflecting more severe pulmonary compromise (3.5 ± 0.2 versus 2.8 ± 0.3). MSC infusion was safe and well tolerated. The MSC group had a significantly higher Horovitz score on discharge than the control group. Compared to controls, patients with MSC treatment showed a significantly lower Murray score upon discharge than controls. In the MSC group, 4 out of 5 patients (80%) survived to discharge and exhibited good pulmonary function, whereas only 8 out of 18 patients (45%) in the control group survived to discharge. Conclusion: MSC infusion is a safe treatment for COVID-19 ARDS that improves pulmonary function and overall outcome in this patient population.