Abstract: Songnen plain was divided into climatic zones with thornthwaite humid index. The time lag character of the NDVI to climate change was discussed by using correlation between the SPOT/VGT NDVI and meteorological data. The results showed that there were significant positive correlation between NDVI and mean temperature, mean minimum temperature, mean maximum temperature 10 day (P＜0.01), between NDVI and precipitation, relative humidity 10 day (P<0.05). The minimum temperature 10 day was restrictive factor to NDVI. Precipitation was the most important contributor to NDVI in humid and semihumid area, but the relative humidity was more important to NDVI than precipitation in semi arid area. Time lag of NDVI to temperature was 20 days in humid region, 20~30 days in semihumid region and 30 days in semi arid days, and which to precipitation was 30 days in humid region, 20 days in semihumid region and 10 days in semi arid days. Time lag of NDVI to humidity was shorter than that to precipitation.

Key words: Songnen plain, NDVI, Meteorological factors, Climatic zones, Time lag