The verification of climate drought dynamic monitoring in alpine meadow based on standardized precipitation index and gis

By using monthly precipitation data and standardized precipitation index (SPI), combining the normalized difference vegetation index (NDVI) data and historical statistical data of drought area, the drought trend of Gannan region from 1965 to 2013 was analyzed. The results showed that: (1) from 1965 to 2013, the drought index in study area rose firstly (1965–1976) and leveled off (1977–1989), then decreased (1990–2001) and finally rose again (2000–2012). (2) SPI was closely related to NDVI, y=0.0298x 2 +0.062+0.7678, (R 2 =0.9034), y is the NDVI value of the pixel, x is the SPI value of the meteorological stations. (3) Compared with historical data, SPI6 could reveal the drought conditions in alpine meadows commendably. These results would provide effective theory and method which can support related research in the future study.