GIS and Remote Sensing in Hydrology, Water Resources and Environment (Proceedings of ICGRHWE held at the Three Gorges Dam, China, September 2003). IAHS Publ. 289, 2004, 206-214

Determination of regional heat fluxes over heterogeneous land surfaces

Yaoming Ma1,2, Weiqing Ma1, Maoshan Li1, Zhongbo Su3, Massimo Menenti3, Osamu Tsukamoto4, irohiko Ishikawa5, Toshio Koike6 & JUN WEN1

1 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China

ymma@ns.lzb.ac.cn

2 Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China

3 Alterra Green World Research, P.O.Box 47, 6700 AA, Wageningen, The Netherlands

4 Department of Earth Sciences, Okayama University, Okayama 700, Japan

5 Disaster Prevention Research Institute, Kyoto University, Kyoto 611, Japan

6 Department of Civil Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan

Abstract Arid areas (e.g. desertification area) and high elevation areas (e.g. the Tibetan Plateau) with inhomogeneous landscapes are characterized by extreme gradients in land surface properties such as wetness, roughness and temperature, which have a significant but local impact on the atmospheric boundary layer (ABL). Observation of the actual extent over these areas is essential to understand the mechanisms through which inhomogeneous land surfaces may have a significant impact on the structure and dynamics of the overlying ABL. Progress in this research area requires spatial measurements of variables such as surface hemispherical reflectance, radiometric surface temperature, Normalized Difference Vegetation Index (NDVI), Modified Soil Adjusted Vegetation Index (MSAVI), vegetation coverage, leaf area index (LAI), local aerodynamic roughness length, etc. Imaging radiometric board satellites can provide useful estimates of most of these variables. By using these variables, we can derive the distribution of land surface heat fluxes over inhomogeneous landscape. Parameterization methods to derive the regional land surface variables, vegetation variables and land surface heat fluxes over inhomogeneous landscapes by using NOAA/AVHRR data, Landsat TM data and field observations have been proposed in this study. The method was applied to the areas of the GAME/Tibet and the HEIFE.

Key words field observations; heterogeneous landscape; regional land surface heat fluxes; satellite remote sensing