中国温带草原植被NDVI时空变化及其对气候变化的响应

Spatiotemporal variation of vegetation NDVI and its response to climate change in the temperate grassland region of China

为探究中国温带草原植被变化及其对气候变化的响应规律,本文利用1982—2015年逐月气象数据和逐旬GIMMS NDVI数据,分析了中国温带草原区不同类型草原植被NDVI变化特征及其对气候变化的响应。结果表明:中国温带草原植被生长季NDVI在1982—2015年总体呈增加趋势,增加速率为0.008 (10 a^(-1));在生长季内的不同季节,温带草原植被NDVI均呈增加趋势,但存在一定的空间差异;生长季内,降水是中国温带草原植被生长最重要的影响因子,春季和夏季降水的增多明显促进温带草原3种类型植被的生长;在气温影响方面,春季夜晚最低温的升高对于所有类型温带草原植被生长均有促进作用,而春季和秋季白天最高温的升高能够明显促进温带草甸草原和典型草原植被的生长。本研究发现,夏季夜晚最低温和白天最高温对中国温带草原植被有不对称的影响,夜晚最低温的增加会促进植被的生长,而白天最高温的增加对植被生长起到抑制作用。

We analyzed the spatiotemporal variation of vegetation NDVI and its response to climate change in the temperate grassland region of China based on GIMMS NDVI and monthly climate data from 1982 to 2015. The results showed that the growing season NDVI of temperate grasslands in China showed an increasing trend(0.008(10 a^(-1))) during 1982-2015. In different seasons of the growing season, the NDVI of temperate grasslands in China generally showed an increasing trend, but with an obvious spatial heterogeneity. During the growing season, precipitation was the most important factor affecting vegetation growth of temperate grasslands. The increase of precipitation in the growing season(especially in spring and summer) significantly promoted the growth of temperate grasslands. In terms of temperature effects, the increasing night-time minimum temperature in spring was beneficial to the growth of temperate grasslands, while the increase of daytime maximum temperature in spring and autumn obviously promoted the growth of temperate meadow steppe and typical steppe. The daytime maximum temperature and night-time minimum temperature had asymmetric effects on temperate grasslands in summer. Specifically, the increase of daytime maximum temperature in summer could inhibit vegetation growth, while the increase of night-time minimum temperature in summer could promote the growth of temperate grasslands in China.