气候变化对生态脆弱区的植被影响很大,草原植被极易受气候变化的影响。为了解草原区对气候变化的响应,保护该区植被健康生长,运用多个气候要素(温度、风速、降水)和SPEI指数进行突变分析和趋势分析,利用MODIS NDVI数据和温度、风速、降水及SPEI指数进行相关性研究,通过BP网络模型对NDVI产生响应的气象要素进行了预测。结果 表明:19世纪后的典型草原区温度随年份变化有显著增加趋势,风速和SPEI指数有显著减小的趋势,20世纪后的降水有减小的趋势。降水、SPEI与NDVI相关性较高,说明降水量是影响典型草原植被生长的主要气候要素,干旱缺水对植物生长有着重要的影响,由于温度对干旱程度有影响,因此温度也影响着该区植物的生长。BP网络模型模拟2019—2038年温度和降水量与以往年份相比,波动不大且没有发生过大的趋势改变。
Climate change has a great impact on vegetation in ecologically fragile areas. Grassland vegetation is extremely vulnerable to climate change. In order to understand the response of grassland areas to climate change and protect the healthy growth of vegetation in this area, multi-climatic factors(temperature, wind speed, precipitation)and SPEI index were used for mutation analysis and trend analysis. MODIS NDVI data and temperature, wind speed, precipitation and SPEI index were used to conduct correlation studies, and the meteorological elements responding to NDVI were predicted by BP network model. The results show that the typical grassland temperature and SPEI index had a significant increase trend after the 19th century, the wind speed had a significant decrease trend, and the precipitation had a decrease trend after the 20th century; precipitation, SPEI and NDVI are all highly correlated, indicating that precipitation is the main climatic factor affecting the growth of typical steppe vegetation; the high correlation between SPEI and NDVI indicates that drought degree and water shortage have an important influence on plant growth; as the degree of drought is mainly affected by the control of temperature, the temperature also affects the growth of plants in this area; the fluctuation of temperature and precipitation in 2019—2038 simulated by the BP network model is not big and is no big trend change compared with those of the previous years. In the following few years, the trend of temperature and precipitation is stable.
