江苏省植被动态演变规律及其与极端气候事件的关系

Dynamic variation rules of vegetation cover in Jiangsu Province and its response to climate change

利用1982—2013年江苏省植被归一化指数(NDVI)和13个气象站的气温和降水数据,采用SPI标准化降水指数以及PDSI干旱指数模型,研究江苏省植被动态的演变规律及其与旱涝的关系。结果发现:1江苏全省平均的NDVI值整体呈缓慢上升趋势,但上升趋势不明显,其中苏北地区植被覆盖增加趋势明显,远高于全省平均水平,而苏南地区植被覆盖有减小趋势;2江苏地区多年平均NDVI值有明显的季节变化,冬季的NDVI值为全年最低,春季NDVI值不断增加,到8月份达到最高,之后不断下降;3极端干旱和洪涝对江苏省NDVI值有显著影响,干旱或洪涝年份的NDVI值明显小于正常年份,并且洪涝年份受影响更为明显。春季极端干旱对江苏省NDVI值影响较大,而夏季洪涝事件对江苏省NDVI的影响较大。

Based on the SPI and PDSI drought model, the NDVI derived from GIMMS and climate data provided from 13 metrological station in Jiangsu Province cross 1982 to 2013 were analyzed to explore the relationship between the vegetation cover and extreme droughts and floods. The results showed that the vegetation cover was showing a increasing trend in the past 30 years, and the seasonal vegetation cover varied greatly. The vegetation cover decreased in the southern Jiangsu Province, but increased in the northern Jiangsu Province since 2000. There was a good relationship between the NDVI and extreme droughts or floods in Jiangsu Province, and the lower NDVI value was found in the drought or flood year than that in the normal year. The extreme drought events exerted a great impact on the NDVI in spring, and floods cause the decline of NDVI in summer.