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Author (up) Conradt, T. openurl 
  Title Introduction to the eco-hydrological model SWIM, recent applications and new developments Type Conference Article
  Year 2013 Publication Abbreviated Journal  
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  Area Expedition Conference Solicited lecture at the Faculty of Agricultural Sciences of Baoding Normal University, Baoding, Hebei, P. R. China, 2013-10-20 to 2013-10-27  
  Notes Approved no  
  Call Number MA @ admin @ Serial 2364  
Permanent link to this record
 

 
Author (up) Conradt, T.; Gornott, C.; Wechsung, F. url  doi
openurl 
  Title Extending and improving regionalized winter wheat and silage maize yield regression models for Germany: Enhancing the predictive skill by panel definition through cluster analysis Type Journal Article
  Year 2016 Publication Agricultural and Forest Meteorology Abbreviated Journal Agricultural and Forest Meteorology  
  Volume 216 Issue Pages 68-81  
  Keywords cluster analysis; crop yield estimation; germany; multivariate regression; silage maize; winter wheat; climate-change; canadian prairies; crop yield; temperature; responses; environments; variability; cultivar; china  
  Abstract Regional agricultural yield assessments allowing for weather effect quantifications are a valuable basis for deriving scenarios of climate change effects and developing adaptation strategies. Assessing weather effects by statistical methods is a classical approach, but for obtaining robust results many details deserve attention and require individual decisions as is demonstrated in this paper. We evaluated regression models for annual yield changes of winter wheat and silage maize in more than 300 German counties and revised them to increase their predictive power. A major effort of this study was, however, aggregating separately estimated time series models (STSM) into panel data models (PDM) based on cluster analyses. The cluster analyses were based on the per-county estimates of STSM parameters. The original STSM formulations (adopted from a parallel study) contained also the non-meteorological input variables acreage and fertilizer price. The models were revised to use only weather variables as estimation basis. These consisted of time aggregates of radiation, precipitation, temperature, and potential evapotranspiration. Altering the input variables generally increased the predictive power of the models as did their clustering into PDM. For each crop, five alternative clusterings were produced by three different methods, and similarities between their spatial structures seem to confirm the existence of objective clusters about common model parameters. Observed smooth transitions of STSM parameter values in space suggest, however, spatial autocorrelation effects that could also be modeled explicitly. Both clustering and autocorrelation approaches can effectively reduce the noise in parameter estimation through targeted aggregation of input data. (C) 2015 Elsevier B.V. All rights reserved.  
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  ISSN 0168-1923 ISBN Medium Article  
  Area Expedition Conference  
  Notes CropM, ft_macsur Approved no  
  Call Number MA @ admin @ Serial 4709  
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Author (up) Conradt, T.; Hattermann, F.F.; Koch, H.; Wechsung, F. openurl 
  Title Klima- und Landnutzungsszenarien in ihren Wirkungen auf den Wasserabfluss Type Book Chapter
  Year 2013 Publication Abbreviated Journal  
  Volume Issue Pages 177-209  
  Keywords CropM  
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  Publisher Weißensee Verl. Place of Publication Berlin Editor Wechsung, F.; Hartje, V.; Kaden, S.; Venohr, M.; Hansjürgens, B.; Gräfe, P.  
  Language Summary Language Original Title  
  Series Editor Series Title Die Elbe im globalen Wandel Abbreviated Series Title  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number MA @ admin @ Serial 2365  
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Author (up) Conradt, T.; Koch, H.; Hattermann, F.F.; Wechsung, F.; Hartje, V.; Kaden, S.; Venohr, M.; Hansjürgens, B.; Gräfe, P. openurl 
  Title Validierung von Lokalkorrekturen der Verdunstung bei den Simulationen des Wasserabflusses Type Book Chapter
  Year 2013 Publication Abbreviated Journal  
  Volume Issue Pages 211-231  
  Keywords CropM  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Weißensee Verl. Place of Publication Berlin Editor Wechsung, F.; Hartje, V.; Kaden, S.; Venohr, M.; Hansjürgens, B.; Gräfe, P.  
  Language Summary Language Original Title  
  Series Editor Series Title Die Elbe im globalen Wandel Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number MA @ admin @ Serial 2367  
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Author (up) Conradt, T.; Wechsung, F.; Bronstert, A. url  doi
openurl 
  Title Three perceptions of the evapotranspiration landscape: comparing spatial patterns from a distributed hydrological model, remotely sensed surface temperatures, and sub-basin water balances Type Journal Article
  Year 2013 Publication Hydrology and Earth System Sciences Abbreviated Journal Hydrol. Earth System Sci.  
  Volume 17 Issue 7 Pages 2947-2966  
  Keywords senegal river-basin; data assimilation; sensing data; regional evapotranspiration; intercomparison project; environmental-models; oklahoma experiments; solar-radiation; satellite data; scale  
  Abstract A problem encountered by many distributed hydrological modelling studies is high simulation errors at interior gauges when the model is only globally calibrated at the outlet. We simulated river runoff in the Elbe River basin in central Europe (148 268 km(2)) with the semi-distributed eco-hydrological model SWIM (Soil and Water Integrated Model). While global parameter optimisation led to Nash-Sutcliffe efficiencies of 0.9 at the main outlet gauge, comparisons with measured runoff series at interior points revealed large deviations. Therefore, we compared three different strategies for deriving sub-basin evapotranspiration: (1) modelled by SWIM without any spatial calibration, (2) derived from remotely sensed surface temperatures, and (3) calculated from long-term precipitation and discharge data. The results show certain consistencies between the modelled and the remote sensing based evapotranspiration rates, but there seems to be no correlation between remote sensing and water balance based estimations. Subsequent analyses for single sub-basins identify amongst others input weather data and systematic error amplification in inter-gauge discharge calculations as sources of uncertainty. The results encourage careful utilisation of different data sources for enhancements in distributed hydrological modelling.  
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  Series Volume Series Issue Edition  
  ISSN 1607-7938 ISBN Medium Article  
  Area Expedition Conference  
  Notes CropM Approved no  
  Call Number MA @ admin @ Serial 4485  
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