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The fluctuation of vegetation water condition around desert area is one of most important parameters to interpret the
desertification expansion. United Nations reported that about 35 million square kilometers of land are subject to
desertification. Historically, many parts of China have been suffered from severe desertification. This paper attempts an
analysis for spatio-temporal variation characteristics of vegetation drought status around China and Mongolia desert with
remotely sensed data. Time series images (1 January, 1999 - 31 December 2006) obtained from SPOT/VEGETATION
were used to monitor inter-annual variability of water condition. SPOT/VEGETATION satellite, which has a fine
temporal resolution and sensitive to vegetation growth, could be very useful to detect large scale dynamics of
environmental changes and desertification progress. The main objective of the study is analyzing water status around
China and Mongolia desert and predicting a risk area of desertification. In this study, NDWI (Normalized Difference
Water Index) is used to monitor vegetation water condition (drought status) over the study area. To interpret the
relationship between vegetation drought status and vigor, NDVI (Normalized Difference Vegetation Index) was
employed in ensemble with NDWI. Annual total precipitation from NCEP/NCAR reanalysis data is used as subsidiary
data. The study area from 73°36´E to 120°41´E longitude and from 30°81´N to 52°13´N longitude in northern China and
whole Mongolia. NDWI value around desert has a range from -0.05 to -0.35 and NDWI values are decreased during the
study period. Each year precipitation patterns are similar to yearly mean NDWI value. The study detected several areas
where NDWI is dramatically decreased for 8 years, especially northeast part of Mongolian Gobi desert and southeast part
of China Taklamakan desert.
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