LAND COVER ANALYSIS ALONG SEMI-ARID TRANSECTS IN ASIA

摘要

The use of higher spatial scale land cover data for development of regional estimates of land cover types are improving our ability to estimate land use and ecosystem interactions with global climate change. The spatial pattern and area estimates developed using land cover maps estimated from the TM-1 km products will provide a more detailed description of land use and cover for extrapolation of ecosystem dynamics for regional analyses. Since AVHRR data are of low spatial resolution, the land cover types which are classified by AVHRR data need to be of large spatial scale to be picked up by this sensor. The 50~*50 km~2 land cover maps used by mesoscale climate analyses and some ecosystem analyses would have a better representation of the land cover pattern and area estimates for biogeochemical and water flux estimates using the TM-1 km derived products. The difficulty in differentiating small grains of the croplands and the grassland regions contributes to the bias, but the consistent fashion in which the cropland dominants are weighted by the IGBP Discover analysis is conspicuous in this region of Asia. This over-estimate of croplands can contribute to higher estimates of carbon emissions, gaseous N losses, and erosion estimates for this region of the world. The greater spatial heterogeneity of the land cover distribution displayed by the TM-1 km data for this region would result in different interactions with mesoscale climate patterns than those indicated by the IGBP Discover data set (Pielke et al. 1997, Fu and Wei 1993).