Simultaneous flow of water and air across the land surface during runoff

This paper presents an inter-compartment boundary condition for the simulation of surface runoff, soil moisture, and soil air as a coupled system of partial differential equations. The boundary condition is based on a classic leakance approach to balance water between differently mobile regions such as the land surface and subsurface. Present work applies leakances to transfer water and air simultaneously through the land surface for soils, which are connected by an air flux with a steady atmosphere. Shallow flow and two phase flow in a porous medium are sequential calculated in an iteration loop. General criteria are stated to guarantee numerical stability in the coupling loop and for leakances to control inter-compartment fluid fluxes. Using the leakance approach, a numerical model captures typical feedbacks between surface runoff and soil air in near-stream areas. Specifically, displacement of water and air in soils is hampered at full-water saturation over the land surface resulting in enhanced surface runoff in the test cases. Leakance parameters permit the simulation of air out-breaks with reference to air pressures, which fluctuate in the shallow subsurface between two thresholds

Challenges in the Evaluation of Observational Data Trustworthiness From a Data Producers Viewpoint (FAIR+)

Recent discussions in many scientific disciplines stress the necessity of “FAIR” data. FAIR data, however, does not necessarily include information on data trustworthiness, where trustworthiness comprises reliability, validity and provenience/provenance. This opens up the risk of misinterpreting scientific data, even though all criteria of “FAIR” are fulfilled. Especially applications such as secondary data processing, data blending, and joint interpretation or visualization efforts are affected. This paper intends to start a discussion in the scientific community about how to evaluate, describe, and implement trustworthiness in a standardized data evaluation approach and in its metadata description following the FAIR principles. It discusses exemplarily different assessment tools regarding soil moisture measurements, data processing and visualization and elaborates on which additional (metadata) information is required to increase the trustworthiness of data for secondary usage. Taking into account the perspectives of data collectors, providers and users, the authors identify three aspects of data trustworthiness that promote efficient data sharing: 1) trustworthiness of the measurement 2) trustworthiness of the data processing and 3) trustworthiness of the data integration and visualization. The paper should be seen as the basis for a community discussion on data trustworthiness for a scientifically correct secondary use of the data. We do not have the intention to replace existing procedures and do not claim completeness of reliable tools and approaches described. Our intention is to discuss several important aspects to assess data trustworthiness based on the data life cycle of soil moisture data as an example

Towards the construction of representative regional hydro(geo)logical numerical models: Modelling the upper Danube basin as a starting point

Introduction: Pressure on groundwater resources is increasing rapidly by population growth and climate change effects. Thus, it is urgent to quantify their availability and determine their dynamics at a global scale to assess the impacts of climate change or anthropogenically induced pressure, and to support water management strategies. In this context, regional hydrogeological numerical models become essential to simulate the behavior of groundwater resources. However, the construction of global hydrogeological models faces a lot of challenges that affect their accuracy.Methods: In this work, using the German portion of the Upper Danube Basin (∼43,000 km2) we outline common challenges encountered in parameterizing a regional-scale groundwater model, and provide an innovative approach to efficiently tackle such challenges. The hydrogeological model of the Danube consists of the groundwater finite element code OpenGeoSys forced by the groundwater recharge of the surface hydrological model mHM.Results: The main novelties of the suggested approach are 1) the use of spectral analyses of the river baseflow and a steady state calibration taking as reference the topography to constraint the hydraulic parameters and facilitate the calibration process, and 2) the calibration of the hydraulic parameters for a transient state model by considering parameters derived from the piezometric head evolution.Discussion/conclusion: The results show that the proposed methodology is useful to build a reliable large-scale groundwater model. Finally, the suggested approach is compared with the standard one used by other authors for the construction of global models. The comparison shows that the proposed approach allows for obtaining more reliable results, especially in mountainous areas

Design And Synthesis of a Novel Potent Myelin Basic Protein Epitope 87−99 Cyclic Analogue: Enhanced Stability and Biological Properties of Mimics Render Them a Potentially New Class of Immunomodulators †

A cyclic analogue, [cyclo(87−99)MBP87-99], of the human immunodominant MBP87-99 epitope, was designed based on ROESY/NMR distance information and modeling data for linear epitope 87−99, taking into account T-cell (Phe89, Lys91, Pro96) and HLA (His88, Phe90, Ile93) contact side-chain information. The cyclic analogue was found to induce experimental allergic encephalomyelitis (EAE), to bind HLA-DR4, and to increase CD4 T-cell line proliferation, like that of the conformationally related linear MBP87-99 epitope peptide. The mutant cyclic peptides, the cyclo(91−99)[Ala96]MBP87-99 and the cyclo(87−99)[Arg91Ala96]MBP87-99, reported previously for suppressing, to a varying degree, autoimmune encephalomyelitis in a rat animal model, were found in this study to possess the following immunomodulatory properties:  (i) they suppressed the proliferation of a CD4 T-cell line raised from a multiple sclerosis patient, (ii) they scored the best in vitro TH2/TH1 cytokine ratio in peripheral blood mononuclear cell cultures derived from 13 multiple sclerosis patients, inducing IL-10 selectively, and (iii) they bound to HLA-DR4, first to be reported for cyclic MBP peptides. In addition, cyclic peptides were found to be more stable to lysosomal enzymes and Cathepsin B, D, and H, compared to their linear counterparts. Taken together, these data render cyclic mimics as putative drugs for treating multiple sclerosis and potentially other Th1-mediated autoimmune diseases

Integrating Data Science and Earth Science

This open access book presents the results of three years collaboration between earth scientists and data scientists, in developing and applying data science methods for scientific discovery. The book will be highly beneficial for other researchers at senior and graduate level, interested in applying visual data exploration, computational approaches and scientifc workflows

From Dynamic Groundwater Level Measurements to Regional Aquifer Parameters— Assessing the Power of Spectral Analysis

Large‐scale groundwater models are required to estimate groundwater availability and to inform water management strategies on the national scale. However, parameterization of large‐scale groundwater models covering areas of major river basins and more is challenging due to the lack of observational data and the mismatch between the scales of modeling and measurements. In this work, we propose to bridge the scale gap and derive regional hydraulic parameters by spectral analysis of groundwater level fluctuations. We hypothesize that specific locations in aquifers can reveal regional parameters of the hydraulic system. We first generate ensembles of synthetic but realistic aquifers which systematically differ in complexity. Applying Liang and Zhang’s (2013), https://doi.org/10.1016/j.jhydrol.2012.11.044, semi‐analytical solution for the spectrum of hydraulic head time series, we identify for each ensemble member and at different locations representative aquifer parameters. Next, we extend our study to investigate the use of spectral analysis in more complex numerical models and in real settings. Our analyses indicate that the variance of inferred effective transmissivity and storativity values for stochastic aquifer ensembles is small for observation points which are far away from the Dirichlet boundary. Moreover, the head time series has to cover a period which is roughly 10 times as long as the characteristic time of the aquifer. In deterministic aquifer models we infer equivalent, regionally valid parameters. A sensitivity analysis further reveals that as long as the aquifer length and the position of the groundwater measurement location is roughly known, the parameters can be robustly estimated.Plain Language Summary: We build large‐scale (regional) computer models of the subsurface flow conditions in order to quantify the long‐term shift in groundwater storage and response on the national level under changing climatic conditions and increasing human water demands. These models must be fed with hydrogeological parameters obtained from subsurface observation wells, drilling logs, and hydraulic tests in conjunction with (hydro)geological and geostatistical methods. In some regions these wells are sparsely distributed and derived parameters are representative only for small areas. We hypothesize that groundwater level records can reveal regional aquifer information when analyzed in the spectral domain. In order to bridge that scale gap and because groundwater level time series are generally available, we propose to infer regional parameters by analyzing the frequency content (spectrum) of long groundwater level time series. The required parameters were determined using mathematical formulations of the theoretical spectrum for simplified settings. We tested the methodology in computer models with limited complexity and found that the groundwater level time series indeed contain regional information if the time of observation is sufficiently long. Lastly, we apply the spectral analysis to real groundwater data to test the capability of the method to infer regional aquifer parameters in real aquifers.Key Points: We successfully tested the spectral analysis of groundwater level fluctuations in numerical models and obtained regional aquifer parameters. In a sensitivity analysis of the spectral analysis using field data, the storativity and the response times could be robustly estimated. The application of the suggested methodology to the field data from a catchment in central Germany produced plausible results.Helmholtz Centre for Environmental Research (UFZ)Global Resource WaterGerman Federal Ministry of Education and Research (BMBF)IDAEA‐CSICBarcelona City Councilhttps://github.com/ufz/ogs5https://geostat-framework.github.io

From Dynamic Groundwater Level Measurements to Regional Aquifer Parameters— Assessing the Power of Spectral Analysis

Large-scale groundwater models are required to estimate groundwater availability and to inform water management strategies on the national scale. However, parameterization of large-scale groundwater models covering areas of major river basins and more is challenging due to the lack of observational data and the mismatch between the scales of modeling and measurements. In this work, we propose to bridge the scale gap and derive regional hydraulic parameters by spectral analysis of groundwater level fluctuations. We hypothesize that specific locations in aquifers can reveal regional parameters of the hydraulic system. We first generate ensembles of synthetic but realistic aquifers which systematically differ in complexity. Applying Liang and Zhang’s (2013), https://doi.org/10.1016/j.jhydrol.2012.11.044, semi-analytical solution for the spectrum of hydraulic head time series, we identify for each ensemble member and at different locations representative aquifer parameters. Next, we extend our study to investigate the use of spectral analysis in more complex numerical models and in real settings. Our analyses indicate that the variance of inferred effective transmissivity and storativity values for stochastic aquifer ensembles is small for observation points which are far away from the Dirichlet boundary. Moreover, the head time series has to cover a period which is roughly 10 times as long as the characteristic time of the aquifer. In deterministic aquifer models we infer equivalent, regionally valid parameters. A sensitivity analysis further reveals that as long as the aquifer length and the position of the groundwater measurement location is roughly known, the parameters can be robustly estimated.This work was funded by the Helmholtz Centre for Environmental Research (UFZ) in Leipzig. The authors would like to thank three anonymous reviewers for constructive feedback which improved the quality of this paper. Furthermore, we thank Rohini Kumar for providing the mHM recharge time series, Falk Hesse and Sebastian Müller for support with the stochastic analysis as well as for help with the model setup. Thanks to Lennart Schüler for mathematical support concerning the analytical solutions and Fanny Sarrazin for providing concepts for the sensitivity analysis. We would like to thank the group of the groundwater initiative at UFZ, especially Christian Siebert and Tino Rödiger for constructive feedback about the results of the spectral analysis, the selection of the groundwater wells, and corresponding data sets. The scientific results have been computed at the High-Performance Computing (HPC) Cluster EVE, a joint effort of both the Helmholtz Centre for Environmental Research - UFZ (http://www.ufz.de/) and the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig (http://www.idiv-biodiversity.de/). E. Pujades and S. Attinger greatfully acknowledge the support from the research initiative Global Resource Water (GRoW; 02WGR1423A-F). GRoW is part of the Sustainable Water Management (NaWaM) funding priority within the Research for Sustainable Development (FONA) framework of the German Federal Ministry of Education and Research (BMBF). E. Pujades acknowledges the financial support from IDAEA-CSIC, which is a Centre of Excellence Severo Ochoa (Spanish Ministry of Science and Innovation, Project CEX2018-000794-S), and the Barcelona City Council through the Award for Scientific Research into Urban Challenges in the City of Barcelona 2020 (20S08708). Open access funding enabled and organized by Projekt DEAL.Peer reviewe

Do wastewater pollutants impact oxygen transfer in aerated horizontal flow wetlands?

International audienceAerated treatment wetlands are an increasingly recognized nature-based technology for wastewater treatmentthat relies heavily on mechanical aeration. Although aeration-mediated oxygen transfer into the wastewater canbe impeded by wastewater pollutants, little is known about the link between the volumetric oxygen masstransfer coefficient and the organic carbon concentration of the wastewater in aerated wetlands. In this study,oxygen transfer experiments were carried out in a lab-scale gravel column using clean water and wastewaterfrom a pilot-scale horizontal flow (HF) aerated wetland treating domestic sewage. The-factor, which describesthe ratio of the volumetric oxygen mass transfer coefficient in wastewater to clean water, was reduced byincreasing soluble chemical oxygen demand (CODs). The derived regression equation21.0661.372E-3 mg COD Ls1was incorporated into a numerical process model to simulate the impact of thereduced oxygen transfer on a hypothetical HF aerated wetland. The simulations revealed thatand treatmentefficacy for nitrogen were substantially reduced by CODsat low aeration ( of 1 h−1) and high influent waste-water strength (CODsof 300 mg L−1). At the same and influent CODsconcentration, longitudinal gradients ofand concentrations for dissolved oxygen (DO), NH4-N and NOx-N in the simulated wetland were shifted up to21% of wetland length downstream. These effects decreased with increasing and were found to be negligible at> 3 h−1, which corresponds to an air flow rate of approximately 400 L m−2h−1. Following this, higher organiccarbon concentrations can reduce oxygen transfer in HF aerated wetland systems, thus resulting in decreasedtreatment efficacy