Using in-situ and satellite data for the energy and water cycle study over heterogeneous landscape of the Third Pole region

Abstract:

The exchange of energy and water vapor between land surface and atmosphere over the Tibetan Plateau area play an important role in the Asian monsoon system, which in turn is a major component of both the energy and water cycles of the global climate system. Supported by the Chinese Academy of Sciences and some international organizations, a Third Pole Environment (TPE) Research Platform (TPEP) is now implementing over the Tibetan Plateau and surrounding area. The background of the establishment of the TPEP, the establishing and monitoring plan of long-term scale (5-10 years) of the TPEP will be shown firstly. Then the preliminary observational analysis results, such as the characteristics of land surface heat fluxes, and evapotranspiration (ET) partitioning, the characteristics of atmospheric variables, the structure of the Atmospheric Boundary Layer (ABL) and the turbulent characteristics have also been shown in this study.

The study on the regional distribution of land surface heat fluxes and ET are of paramount importance over heterogeneous landscape of the Tibetan Plateau. The parameterization method based on satellite data and the ABL observations has been proposed and tested for deriving regional distribution and their ten years variations of land surface variables, land surface heat fluxes and ET over heterogeneous landscape of the whole Tibetan Plateau area. To validate the proposed method, the ground-measured s land surface variables and surface heat fluxes in the TPEP are compared to satellite derived values. The results show that the derived land surface variables, land surface heat fluxes and ET over the study area are in good accordance with the land surface status. These parameters show a wide range due to the strong contrast of surface features. The sensible heat flux is decreasing while the latent heat flux is increasing from 2001 to 2010 over the whole Tibetan Plateau. And the estimated land surface variables and land surface heat fluxes are in good agreement with ground measurements, and all their absolute percent difference is less than 10% in the validation sites. It is therefore concluded that the proposed methods are successful for the retrieval of land surface variables, land surface heat fluxes and ET over heterogeneous landscape of the Tibetan Plateau area.