内蒙古植被生长峰值期时空动态变化及其对气候因子的响应

Spatial and Temporal Dynamics of Annual Peak Growth of Vegetation and Its Response to Climate Change in Inner Mongolia

基于GIMMSNDVI和MODISNDVI数据,利用一元六次多项式函数拟合法,识别内蒙古植被生长峰值期(peakofgrowingseason,POS)时空变化,并在生态区尺度上分析植被生长峰值期与气象因子的相关性。结果表明,1982—2019年,内蒙古植被生长峰值期为第200—230天,即7月中旬至8月下旬,呈显著推迟趋势(0.12天/年)。森林生态区的植被生长峰值期较早,平均为第209天;草原生态区的植被生长峰值期主要分布在第210—225天,平均为第215天;荒漠生态区的植被生长峰值期晚于草原生态区,平均为第218天。1982—2019年3个生态区的变化趋势相同,呈推迟趋势,其中荒漠生态区显著推迟。森林和荒漠生态区植被生长峰值期受降水影响较大,而草原生态区受温度影响较大。

In the study,the spatial and temporal variations of the peak of growing season(POS)in Inner Mongolia were identified based on GIMMS NDVI and MODIS NDVI data by using the function fitting method of univariate sixth degree polynomial,and the correlations between the peak of growing season and meteorological factors were analyzed at the ecological region scale.The results showed that during 1982-2019,the peak growing period of vegetation in Inner Mongolia mainly appeared within the 200th-230th day,namely,from the middle of July to the end of August,and also presented a significant delay trend with passing of the year(0.12 days/year).The peak period of vegetation growth in the forest region was earlier,appeared on the 209th day on the average;while that in the grassland region mainly appeared on the 210th-225th day,the 215th day on the average and that in desert was later than that in grassland,appeared on the 218th day on the average.Over all,the changing trend of the peak of growing season for the three kinds of vegetation region was the similar from 1982 to 2019,showing a delayed trend,especially desert being significantly delayed for desert.The research also found that the peak growth period of forest and desert was more affected by precipitation,while that of the grassland was more affected by temperature in Inner Mongolia.