青藏高原NDVI对ENSO事件的响应

Response of Tibetan Plateau Vegetation to ENSO Events

以NCEP/NCAR所发布的1950~1979年全球海平面温度(SST)数据为基础,得到了1980~2006年ENSO事件的3个典型阶段,即冷阶段、中性阶段和暖阶段。通过分析1982~2005年的NOAA-AVHRR NDVI影像数据,得到了在不同ENSO阶段青藏高原生长季(5~9月)和冬季(12~2月)的NDVI平均值和离差图。结果表明:在生长季,冷阶段的NDVI高于其他两个阶段;在冬季,高原上的NDVI在正常阶段最好,其次为暖阶段,在冷阶段生长状况最低。此外还发现,不同阶段的青藏高原北部和南部植被变化也存在明显差异。

Using the SST data issued by NCEP/NCAR from 1950 to 1979,We have obtained three phases of ENSO envents,which are called as cold phase,normal phase,and warm phase.For each phase,the NDVI average values and the pictures of standardized departure are corresponding to growing season(Apr.-Sep.) and winter season (Oct.-Dec.)have been extracted from the NOAA-AVHRR NDVI images with 1 km resolution ratio in 1982～2005.The results show that vegetation conditions of cold phase are better than the other two phases in growing season,however,in winter season,the vegetation conditions are the best in normal phase,followed by in worm phase,and the worst are in cold phase.Furthermore,the results also present obvious difference in the vegetation change between north and south of Tibetan Plateau.