Abstract: Based on the 1982-2003 GIMMS NDVI data after processed through synthesis, re-sampling, and time-series filtering, and by using the analysis methods of linear trend and empirical orthogonal function (EOF), this paper studied the spatiotemporal variations of vegetation cover in Huang-Huai-Hai area. In the past 22 years, the vegetation NDVI in the whole area had a slightly increasing trend, and the growth season tended to be advanced and prolonged. In most part of the area, vegetation activity enhanced; but in local parts of it, there existed vegetation degradation. The vegetation NDVI indicated an obvious increasing trend in spring but an obvious decreasing trend in summer. According to the dynamic trend of pixel number for different vegetation types, the unchanged types were dominated by forest, shrub, and agricultural vegetations, while grassland vegetation presented an increasing trend. The EOF analysis for NDVI anomaly during main growth seasons showed that the first mode was characterized by positive variation in the central, south, and north regions but negative variation in edging regions, the second mode was characterized by the variation from positive to negative and dominated by positive variation in the direction from southeast to northwest regions, and the third mode was characterized by the variation of positive-negative-positive in the direction from southeast to northwest regions, in which, the regions with negative variation were dominated by forest and single-season agricultural vegetation, while those with positive variation were dominated by cropland and grassland. The third mode approximately reflected the distribution type of NDVI in the farming-pasturing and forest regions of the Huang-Huai-Hai area.

Key words: Agroforestry ecosystem, ³²P, Distribution, Translocation