黄河流域干旱状况变化的气候与植被特征分析

应用干旱的气候分析方法和遥感监测方法,分别利用1982～1998年(1999年)降水和气温气象数据,以及AVHRR的NDVI遥感数据计算了黄河流域气候干旱指数和距平NDVI。以像元为单位,应用线性回归斜率和相关系数分析了流域内干旱状况的气候特征和植被特征的变化状况,并进行了流域干旱状况类型的区域划分,从气候和植被特征方面分析了黄河流域近18年来干旱变化状况。通过研究得出以下结论:黄河流域在1982～1999年间干旱的气候特征比较突出,在101°20'E以东地区受干旱威胁,共占黄河流域面积的71%;黄河流域在101°20'E以西的源头地区,干旱的气候特征和植被特征目前都处在相对减弱的趋势中,干旱没有进一步严重恶化的迹象;黄河流域灌溉农业地区植被基本不受气候干旱的影响。

The analysis of drought related climatic and vegetative features in the Yellow River basin

The Yellow River basin covers a large area,which occupies the most part of North China.The drought is ecological and environmental feature in Yellow River basin.Drought is classified into different types,usually including climatic drought,agricultural drought,hydrological drought and society drought.In this article,we employ the climatic and remote sensing methods to analyze the drought feature s in Yellow River basin on the aspects of climate and vegetation.Based on the precipitation and temperature data and NDVI data of AVHRR from1981to1998(1999),we calculate the value of drought index and NDVI mean deviation in Yellow River basin and use the linear regression slope ratio and correlation model to study the climatic and vegetative features of drought.After comparing the trend of climatic and vegetative features,we divide the drought in the Yellow River basin into four sub-regions and respectively analyze the temporal and spatial features of drought over the last18years.We conclude that the climatic features in the Yellow River basin is obvious during1982to1999and the region to the east of101°20'E,which occupies71%of the Yellow River basin,is threaten by drought;there is no drought trend in the headwater region to the west of101°20' E on the aspect of climate and vegetation;and the vegetation in the irrigated area is not influenced by climatic drought.