101 research outputs found
The importance of vegetation in understanding terrestrial water storage variations
Funding Information: The article processing charges for this openaccess publication were covered by the Max Planck Society. Publisher Copyright: © 2022 Tina Trautmann et al.So far, various studies have aimed at decomposing the integrated terrestrial water storage variations observed by satellite gravimetry (GRACE, GRACE-FO) with the help of large-scale hydrological models. While the results of the storage decomposition depend on model structure, little attention has been given to the impact of the way that vegetation is represented in these models. Although vegetation structure and activity represent the crucial link between water, carbon, and energy cycles, their representation in large-scale hydrological models remains a major source of uncertainty. At the same time, the increasing availability and quality of Earth-observation-based vegetation data provide valuable information with good prospects for improving model simulations and gaining better insights into the role of vegetation within the global water cycle. In this study, we use observation-based vegetation information such as vegetation indices and rooting depths for spatializing the parameters of a simple global hydrological model to define infiltration, root water uptake, and transpiration processes. The parameters are further constrained by considering observations of terrestrial water storage anomalies (TWS), soil moisture, evapotranspiration (ET) and gridded runoff (Q) estimates in a multi-criteria calibration approach. We assess the implications of including varying vegetation characteristics on the simulation results, with a particular focus on the partitioning between water storage components. To isolate the effect of vegetation, we compare a model experiment in which vegetation parameters vary in space and time to a baseline experiment in which all parameters are calibrated as static, globally uniform values. Both experiments show good overall performance, but explicitly including varying vegetation data leads to even better performance and more physically plausible parameter values. The largest improvements regarding TWS and ET are seen in supply-limited (semi-arid) regions and in the tropics, whereas Q simulations improve mainly in northern latitudes. While the total fluxes and storages are similar, accounting for vegetation substantially changes the contributions of different soil water storage components to the TWS variations. This suggests an important role of the representation of vegetation in hydrological models for interpreting TWS variations. Our simulations further indicate a major effect of deeper moisture storages and groundwater-soil moisture-vegetation interactions as a key to understanding TWS variations. We highlight the need for further observations to identify the adequate model structure rather than only model parameters for a reasonable representation and interpretation of vegetation-water interactions.publishersversionpublishe
Water scarcity under scenarios for global climate change and regional development in semiarid Northeastern Brazil
Delayed subsidence of the Dead Sea shore due to hydro-meteorological changes
Many studies show the sensitivity of our environment to manmade changes, especially the anthropogenic impact on atmospheric and hydrological processes. The effect on Solid Earth processes such as subsidence is less straightforward. Subsidence is usually slow and relates to the interplay of complex hydro-mechanical processes, thus making relations to atmospheric changes difficult to observe. In the Dead Sea (DS) region, however, climatic forcing is strong and over-use of fresh water is massive. An observation period of 3 years was thus sufficient to link the high evaporation (97 cm/year) and the subsequent drop of the Dead Sea lake level (â 110 cm/year), with high subsidence rates of the Earthâs surface (â 15 cm/year). Applying innovative Global Navigation Satellite System (GNSS) techniques, we are able to resolve this subsidence of the âSolid Earthâ even on a monthly basis and show that it behaves synchronous to atmospheric and hydrological changes with a time lag of two months. We show that the amplitude and fluctuation period of ground deformation is related to poro-elastic hydro-mechanical soil response to lake level changes. This provides, to our knowledge, a first direct link between shore subsidence, lake-level drop and evaporation
The Electrophilicity of Surface Carbon Species in the Redox Reactions of CuOâCeO<sub>2</sub> Catalysts
Electronic metalâsupport interactions (EMSI) describe the electron flow between metal sites and a metal oxide support. It is generally used to follow the mechanism of redox reactions. In this study of CuOâCeO2 redox, an additional flow of electrons from metallic Cu to surface carbon species is observed via a combination of operando Xâray absorption spectroscopy, synchrotron Xâray powder diffraction, near ambient pressure near edge Xâray absorption fine structure spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy. An electronic metalâsupportâcarbon interaction (EMSCI) is proposed to explain the reaction pathway of CO oxidation. The EMSCI provides a complete picture of the mass and electron flow, which will help predict and improve the catalytic performance in the selective activation of CO2, carbonate, or carbonyl species in C1 chemistry
Sustainability of Small Reservoirs and Large Scale Water Availability Under Current Conditions and Climate Change
Anthracycline rechallenge using pegylated liposomal doxorubicin in patients with metastatic breast cancer: a pooled analysis using individual data from four prospective trials
BACKGROUND: The aim of this study was to determine the activity of anthracycline rechallenge using pegylated liposomal doxorubicin (PLD) in patients with metastatic breast cancer (MBC) previously treated with conventional anthracyclines. METHODS: Pooled individual data from four prospective trials were used, and the primary end point of the pooled analysis was clinical benefit rate (CBR). The studies comprised 935 patients, of whom 274 had received PLD in the metastatic setting after prior exposure to conventional anthracyclines (rechallenge population). RESULTS: The majority of patients were heavily pretreated. Previous anthracycline therapy was administered in the adjuvant (14%) or metastatic setting (46%), or both (40%). The overall CBR from rechallenge with PLD was 37.2% (95% CI, 32.4-42.0). In univariate analyses, the CBR was significantly higher in patients with less exposure to prior chemotherapy, in taxane-naive patients, and in patients with a favourable Eastern Cooperative Group performance status of 0 vs 1 vs 2 (53.3 vs 35.5 vs 18.2%; P<0.001). In multivariate analyses, performance status proved to be the only independent predictor of the CBR achieved with PLD rechallenge (P=0.038). There was no statistically significant difference in CBR regarding the setting, cumulative dose of and/or resistance to prior anthracyclines, or time since prior anthracycline administration. CONCLUSION: Anthracycline rechallenge using PLD is effective in patients with MBC who have a favourable performance status, regardless of setting, resistance, cumulative dose or time since prior conventional anthracycline therapy. British Journal of Cancer (2010) 103, 1518-1523. doi:10.1038/sj.bjc.6605961 www.bjcancer.com Published online 26 October 2010 (C) 2010 Cancer Research U
Precision of the current methods to measure the alkenone proxy UK'37 and absolute alkenone abundance in sediments : results of an interlaboratory comparison study
Measurements of the UK'37 index and the absolute abundance of alkenones in marine sediments are increasingly used in paleoceanographic research as proxies of past sea surface temperature and haptophyte (mainly coccolith-bearing species) primary productivity, respectively. An important aspect of these studies is to be able to compare reliably data obtained by different laboratories from a wide variety of locations. Hence the intercomparability of data produced by the research community is essential. Here we report results from an anonymous interlaboratory comparison study involving 24 of the leading laboratories that carry out alkenone measurements worldwide. The majority of laboratories produce data that are intercomparable within the considered confidence limits. For the measurement of alkenone concentrations, however, there are systematic biases between laboratories, which might be related to the techniques employed to quantify the components. The maximum difference between any two laboratories for any two single measurements of UK'37 in sediments is estimated, with a probability of 95%, to be <2.18C. In addition, the overall within-laboratory precision for the UK'37 temperature estimates is estimated to be <1.68C (95% probability). Similarly, from the analyses of alkenone concentrations the interlaboratory reproducibility is estimated at 32%, and the repeatability is estimated at 24%. The former is compared to a theoretical estimate of reproducibility and found to be excessively high. Hence there is certainly scope and a demonstrable need to improve reproducibility and repeatability of UK'37 and especially alkenone quantification data across the community of scientists involved in alkenone research
Metabolomic Plasticity in GM and Non-GM Potato Leaves in Response to Aphid Herbivory and Virus Infection
An important aspect of ecological safety of genetically
modified
(GM) plants is the evaluation of unintended effects on plantâinsect
interactions. These interactions are to a large extent influenced
by the chemical composition of plants. This study uses NMR-based metabolomics
to establish a baseline of chemical variation to which differences
between a GM potato line and its parent cultivar are compared. The
effects of leaf age, virus infection, and aphid herbivory on plant
metabolomes were studied. The metabolome of the GM line differed from
its parent only in young leaves of noninfected plants. This effect
was small when compared to the baseline. Consistently, aphid performance
on excised leaves was influenced by leaf age, while no difference
in performance was found between GM and non-GM plants. The metabolomic
baseline approach is concluded to be a useful tool in ecological safety
assessment
Intra-European Movement: Multi-Level or Mismatched Governance?
The case of intra-EU mobility raises significant debate about multi-level governance (MLG) both in analytical terms â how multi-level is governance of intra-EU mobility, what actors are involved and how? â and normative terms â can intra-EU mobility be seen as âsuccessfulâ multi-level governance? Intra-EU mobility is an area that faces both issue complexity and institutional complexity (Stephenson, 2013, pp. 817) and as such, the governance arrangements are often correspondingly complex. This chapter will attempt to locate the case of intra-EU mobility within the broader literature on multi-level governance and try to draw out lessons for understanding MLG as a practical, analytical and normative concept. This is relevant to both the understanding of intra-EU mobility and the understanding of MLG. On the one hand, additional cases help to support or refute the robustness of our conceptualisation of multi-level governance; on the other hand, MLG as a concept can help us to understand the entanglement of a complex issue that cuts across political and policy bounds. The chapter will first develop a framework of multi-level governance that can be applied to intra-EU migration. Then, the structural, relational and policy factors that affect MLG will be explored in the context of this specific case. The final section will try to craft some answers about what intra-EU migration policy can tell us about multi-level governance, and vice versa
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