沂蒙山区植被NDVI的时空特征及其对水热条件的响应

Spatiotemporal Patterns of NDVI and Its Responses to Temperature and Precipitation over Yimeng Mountainous Area

植被是生态环境变化的综合指示器，研究其对水热条件的响应已成为当前气候变化研究中的主要内容之一。选取北方土石山区典型代表——沂蒙山区为研究对象，基于沂蒙山区1980～2010年的气温、降水和2001-2010年MODIS-NDVI数据，结合相关分析和最小二乘法，定量分析该区植被指数的年际、年内的时空变化及其对水热条件的响应。结果表明：①近10a沂蒙山区NDVImax的变化斜率为0．0026；②植被显著退化区和良好区分别占研究区总面积的10．52％和28．62％；③不同季节（主要是春、夏和秋季）植被状况均呈现良性发展趋势；④台站数据显示植被年际变化与年降水和年均气温的关系并不密切，而在月时间尺度上植被与气温的相关性要强于与降水的相关性。综上所述，沂蒙山区植被状况总体呈良性发展趋势，气温可能是影响该区植被生长的主导因子。

Vegetation plays an important role in the climate change, and climate change affects vegetation growth and its photosynthetic activity in return. In this study,we combined datasets of satellite-derived Normalized Differ- ence Vegetation Index （NDVI） from 2001 to 2010 and climatic factors to analyze spatiotemporal patterns of vegeta- tion growth and its responses to temperature and precipitation over Yimeng Mountainous Area which is the typical region of rocky mountain areas in Northern China. To clarify the trends of the temperature and precipitation,data- sets from 1980 to 2010 are used. Our results show that vegetation growth appeared a trend of improvement in the past decade, and the slope of the Max-NDVI is 0.0026 over Yimeng Mountainous Area. In past decade, the signifi- cant area of vegetation degradation accounted for 10.52%of the total study area,however,vegetation growth over 28% of study area was well-grown significantly. In the annual scale, the benign development trends of vegetation condition from different seasons were the same as annual trend, especially in the summer and autumn. Datasets from weather stations show that inter-annual variation of vegetation growth has a weak relationship between annual pre- cipitation and mean annual temperature. In monthly scale, although vegetation growth correlated better with tem- perature than precipitation, the responses in various regions were different to monthly variations of temperature and precipitation. Overall,there are significant variations between the spatiotemporal patterns of Yimeng Mountainous Area and responses to temperature and precipitation. What＇s more,this study found that temperature may be the major effective factor which affects vegetation growths in Yimeng Mountain Area.