Journal Article

PreJuSER-17060

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Sensitivity of Latent Heat fluxes to Initial Values and Parameters of a Land-Surface Model

Schwinger, J. ; Kollet, S. ; Hoppe, C. ; Elbern, H.FZJ*

2010
SSSA Madison, Wis.

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Please use a persistent id in citations: doi:10.2136/vzj2009.0190

Abstract: A tangent linear version of the complex soil-vegetation-atmosphere transfer model Community Land Model has been developed and its ability to reproduce relevant sensitivities of the modeled soil moisture and latent heat flux (LE) evolution to a number of different parameters on a short time scale (3 d) was analyzed. To this end, a series of idealized experiments for different soil moisture states and three different soil types was conducted. We found that the tangent linear model performs well for a large range of conditions. Situations in which the linear approximation potentially fails were connected with the occurrence of saturation and with the highly nonlinear parameterization of water availability to plants. The sensitivity of LE with respect to the model's initial soil moisture state was calculated and compared with the LE sensitivity to soil texture, leaf area index (LAI), and vegetation roughness length. These sensitivities were found to be highly variable with soil type and soil moisture. Our results confirm that soil texture and LAI are key parameters that have a dominant influence on modeled LE under specific environmental conditions. As a preparatory study to soil data assimilation developments, the results also serve to quantify model uncertainties due to limited knowledge of forcing processes and model parameters.

Keyword(s): J

Note: This work was funded by Deutsche Forschungsgemeinschaft (DFG) in the framework of the SFB/TR 32 "Patterns in Soil-Vegetation-Atmosphere Systems: Monitoring, Modeling and Data Assimilation." The National Center for Atmospheric Research (NCAR) is gratefully acknowledged for providing the CLM source code and input data sets. The tangent linear CLM source code was generated using the TAPENADE soft ware provided by the Institut National de Recherche en Informatique et en Automatique (INRIA). The authors thank two anonymous reviewers for their constructive comments and suggestions, which helped improve the manuscript.

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Contributing Institute(s):

1. Troposphäre (IEK-8)

Research Program(s):

1. Atmosphäre und Klima (P23)

Appears in the scientific report 2010
Notes: Nachtrag

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