Publication Date:
2009-10-08
Description:
The skill of the land surface model HTESSEL is assessed to reproduce evaporation in response to land surface characteristics and atmospheric forcing, both being spatially variable. Evaporation estimates for the 2005 growing season were obtained from satellite observations of the Western part of Hungary and compared to model outcomes. Atmospheric forcing was obtained from a hindcast run with the Regional Climate Model RACMO. Although HTESSEL slightly underestimated the seasonal evaporative fraction, the mean, 10th and 90th percentile of this variable were of the same magnitude as the satellite observations. The initial water as stored in the soil and snow layer did not have a significant effect on the statistical properties of the evaporative fraction. However, the spatial distribution of the initial soil and snow water affected significantly the spatial distribution of the calculated evaporative fraction and the models ability to reproduce evaporation correctly in low precipitation areas in the considered region. HTESSELs performance appears to be less in dryer areas. In Western Hungary these areas are situated in the Danube valley, which is partly covered by irrigated cropland and which also may be affected by shallow groundwater. Incorporating (lateral) groundwater flow and irrigation, processes that are not included now, may improve HTESSELs ability to predict evaporation correctly. Evaluation of the model skills using other test areas and larger evaluation periods is needed to confirm the results. Based on earlier sensitivity analysis, the effect of a number of modifications to HTESSEL was assessed. A more physically based reduction function for dry soils was introduced, the soil depth was made variable and the effect of swallow groundwater included. However, the modification did not lead to significant improved performance of HTESSEL.
Print ISSN:
1812-2108
Electronic ISSN:
1812-2116
Topics:
Geography
,
Geosciences
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