干旱区生态环境知识资源中心

Understanding the soil freezing and thawing processes of temperate desert ecosystem on the Qinghai-Tibet Plateau, especially considering that soil freezing and thawing is very sensitive to climate changes. Little changes of soil freezing or thawing may lead to changes in water and heat transition in soils and thus affect the structure and function of ecosystems. SHAW, as a physically based, Land-surface model, provides a useful tool for understanding and analyzing soil freezing and thawing processes. In this paper, using the measured data of temperate desert ecosystem in Dachaidan assessed the model performance in simulating soil freezing and thawing processes. Comparison of the simulated results by SHAW to the measured data showed that in the initial stage of freezing the simulated frozen depth was thinner than the measured; in the thawing period the simulated thawing rate was higher than the measured due to the overestimated soil temperature below 10 cm; however, for the most cold stage ( the stable frozen stage), the simulated matched quite well with the measured. For the maximum frozen depth the simulation only overestimated by as much as 4%. On the whole, the SHAW model performed satisfactorily. This provides a good base for further application of LSMs to the temperate desert ecosystem on the Qinghai-Tibet Plateau. (C) 2010 Published by Elsevier Ltd.