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Institution

Swiss Federal Institute for Forest, Snow and Landscape Research

FacilityBirmensdorf, Switzerland
About: Swiss Federal Institute for Forest, Snow and Landscape Research is a facility organization based out in Birmensdorf, Switzerland. It is known for research contribution in the topics: Climate change & Soil water. The organization has 1256 authors who have published 3222 publications receiving 161639 citations. The organization is also known as: WSL.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a real-time implementation of the radar ensemble generator coupled with a semi-distributed hydrological model in the framework of the forecast demonstration project MAP D-PHASE is presented.
Abstract: An elegant solution to characterise the residual errors in radar precipitation estimates is to generate an ensemble of precipitation fields. The paper proposes a radar ensemble generator designed for usage in the Alps using LU decomposition (REAL), and presents first results from a real-time implementation coupling the radar ensemble with a semi-distributed rainfall-runoff model for flash flood modelling in a steep Alpine catchment. Each member of the radar ensemble is a possible realisation of the unknown true precipitation field given the observed radar field and knowledge of the space-time error structure of radar precipitation estimates. Feeding the alternative realisations into a hydrological model yields a distribution of response values, the spread of which represents the sensitivity of runoff to uncertainties in the input radar precipitation field. The presented ensemble generator is based on singular value decomposition of the error covariance matrix, stochastic simulation using the LU decomposition algorithm, and autoregressive filtering. It allows full representation of spatial dependence of the mean and covariances of radar errors. This is of particular importance in a mountainous region with large uncertainty in radar precipitation estimates and strong dependence of error structure on location. The real-time implementation of the radar ensemble generator coupled with a semi-distributed hydrological model in the framework of the forecast demonstration project MAP D-PHASE is one of the first experiments of this type worldwide, and is a fully novel contribution to this evolving area of applied research. Copyright c ! 2009 Royal Meteorological Society

225 citations

Journal ArticleDOI
TL;DR: A conceptual framework that integrates knowledge and approaches from complex natural systems can be used to increase agricultural resource-use efficiency and productivity is presented and avenues for new research toward an ecologically sustainable and climate-smart future are discussed.
Abstract: In agricultural and natural systems researchers have demonstrated large effects of plant–soil feedback (PSF) on plant growth. However, the concepts and approaches used in these two types of systems have developed, for the most part, independently. Here, we present a conceptual framework that integrates knowledge and approaches from these two contrasting systems. We use this integrated framework to demonstrate (i) how knowledge from complex natural systems can be used to increase agricultural resource-use efficiency and productivity and (ii) how research in agricultural systems can be used to test hypotheses and approaches developed in natural systems. Using this framework, we discuss avenues for new research toward an ecologically sustainable and climate-smart future.

223 citations

Journal ArticleDOI
TL;DR: In this paper, the authors derived a new formulation for the cover effect, in which the fraction of exposed bed area falls exponentially with increasing sediment flux or decreasing transport capacity, and explore its consequences for the model of bedrock abrasion by saltating bed load.
Abstract: The sediment load of a bedrock river plays an important role in the fluvial incision process by providing tools for abrasion (the tools effect) and by covering and thereby protecting the bed (the cover effect). We derive a new formulation for the cover effect, in which the fraction of exposed bed area falls exponentially with increasing sediment flux or decreasing transport capacity, and explore its consequences for the model of bedrock abrasion by saltating bed load. Erosion rates predicted by the model are higher than those predicted by earlier models. In a closed system, the maximum erosion rate is predicted to occur when sediment supply is equal to transport capacity for a flat bed. By optimizing the channel geometry to minimize the potential energy of the stream and using representative values for both discharge and grain size, we derive equations for the geometry of a bedrock river and explore how predictions for width, slope, and bed cover vary as functions of drainage area, rock uplift rate, and rock strength. The equations predict a dependence of channel width on drainage area similar to the relations using a simple shear stress incision law. The slope-area relationship is predicted to be concave up in a log-log regime, with a curvature dependent on uplift rate. However, this curvature does not deviate sufficiently from a straight line to allow discrimination between models using empirical data. Dependence of channel width and slope on rock uplift rate can be separated into two domains: for low uplift rates, channel geometry is largely insensitive to uplift rate due to a threshold effect. At high uplift rates, there is a power law dependence. Bed cover is predicted to increase progressively downstream and to increase with increasing uplift rate. In our model, the width-to-depth ratio is a function of both tectonic and climatic forcing. This indicates that the scaling between channel width and bed slope is neither a unique indicator of tectonic forcing at steady state nor a signature of transience or steady state. We conclude that sediment effects need to be taken into account when modeling bedrock channel morphology.

222 citations

Journal ArticleDOI
TL;DR: Across all the sites, elevated CO₂ increased ¹³C-derived water-use efficiency on average by 73% for Liquidambar styraciflua, 77% for Pinus taeda and 75% for Populus sp.
Abstract: Elevated CO₂ increases intrinsic water use efficiency (WUE(i) ) of forests, but the magnitude of this effect and its interaction with climate is still poorly understood. We combined tree ring analysis with isotope measurements at three Free Air CO₂ Enrichment (FACE, POP-EUROFACE, in Italy; Duke FACE in North Carolina and ORNL in Tennessee, USA) sites, to cover the entire life of the trees. We used δ¹³C to assess carbon isotope discrimination and changes in water-use efficiency, while direct CO₂ effects on stomatal conductance were explored using δ¹⁸O as a proxy. Across all the sites, elevated CO₂ increased ¹³C-derived water-use efficiency on average by 73% for Liquidambar styraciflua, 77% for Pinus taeda and 75% for Populus sp., but through different ecophysiological mechanisms. Our findings provide a robust means of predicting water-use efficiency responses from a variety of tree species exposed to variable environmental conditions over time, and species-specific relationships that can help modelling elevated CO₂ and climate impacts on forest productivity, carbon and water balances.

219 citations

Journal ArticleDOI
01 Jul 1995-Tellus B
TL;DR: In this article, the authors investigated the relationship between tree ring δ 13 C and climate and found that the relative humidity of the atmosphere but also the soil water content can influence the stomatal opening of plant leaves and consequently the photosynthetically fixed carbon.
Abstract: Considerable complexity exists regarding the relationship between tree ring δ 13 C and climate. We proceed from the theoretically derived and experimentally confirmed finding that the relative humidity of the atmosphere but also the soil water content can influence the stomatal opening of plant leaves and consequently the δ 13 C of photosynthetically fixed carbon. Therefore, the potential to reconstruct humidity variations by δ 13 C in tree rings should depend on the water conditions at the site where the trees are growing. We analysed δ 13 C series (3-year ring samples) of cellulose of beech trees ( Fagus silvatica ) covering the time period from 1934 to 1989 for 3 sites in Switzerland: a relatively dry and a humid site close together and another dry site 30 km distant. The δ 13 C series from the two dry sites are closely interrelated and are inversely correlated to the total precipitation amount of the months May + June + July This is most expressed for first differences, i.e., differences of consecutive values, while the long-term trends are more strongly influenced by biological effects. A multivariate analysis shows that at the dry sites, δ 13 C is relatively high for dry/warm summers and low for cool/wet summers. The respective correlations for the humid site are less distinct. In addition, we compared average δ 13 C values for beech, pine and spruce trees from sites differing in soil moisture conditions. For all species we found that the drier the sites the more positive the tree δ 13 C values are. We conclude that at relatively dry sites in temperate-moist climatic conditions, short-term precipitation variations can be reconstructed by δ 13 C measurement on tree rings of beech and probably also of the conifers pine and spruce. DOI: 10.1034/j.1600-0889.47.issue3.4.x

216 citations


Authors

Showing all 1333 results

NameH-indexPapersCitations
Peter H. Verburg10746434254
Bernhard Schmid10346046419
Christian Körner10337639637
André S. H. Prévôt9051138599
Fortunat Joos8727636951
Niklaus E. Zimmermann8027739364
Robert Huber7831125131
David Frank7818618624
Jan Esper7525419280
James W. Kirchner7323821958
David B. Roy7025026241
Emmanuel Frossard6835615281
Derek Eamus6728517317
Benjamin Poulter6625522519
Ulf Büntgen6531615876
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023111
2022173
2021395
2020327
2019269
2018281