青海省植被净初级生产力(NPP)时空格局变化及其驱动因素

植被净初级生产力(NPP)作为陆地生态过程的关键参数,不仅用以估算地球支持能力和评价陆地生态系统的可持续发展,也是全球碳循环的重要组成部分和关键环节。基于2000—2014年MOD17A3年均NPP数据和气象站点气温、降水资料,采用简单差值、趋势分析、相关性分析和Hurst指数等方法,分析了青海省NPP的时空变化特征及其与气候因子的关系。结果表明:①青海省植被年均NPP在2000—2014年间整体分布呈现由南到北、由东到西递减的趋势,各生态区的空间存在显著差异,表现为Ⅱ区>Ⅰ区>Ⅲ区>Ⅳ区>Ⅴ区。②2000—2014年,青海省NPP变化趋势由北到南、由西到东呈现逐渐增加趋势,平均趋势系数为0.61,NPP值增加的区域占总面积的15%,其中显著增加区域为2.8%,轻度增加区域为12.2%。③青海省NPP值的Hurst的值域范围为0—0.39,均值为0.12,除了河流湖泊,建筑用地和未利用土地,青海省NPP变化特征为反持续性特征。④气候因子(年平均降水量和年均气温)对年均NPP的分布有影响,海拔的高低造成气温、降水和土壤的差异,间接影响植被NPP,15年土地利用/覆...

Spatial and temporal patterns of planting NPP and its driving factors in Qinghai Province

As a key parameter of terrestrial ecological process, NPP can not only estimate the earth''s supporting capacity and evaluate the sustainable development of terrestrial ecosystem, but also an important part and key link of global carbon cycle.Based on the MOD17A3 annual net primary productivity data and the meteorological site temperature and precipitation data from 2000 to 2014, the temporal and spatial characteristics of NPP in Qinghai Province and its correlation with climatic factors were analyzed by means of simple difference, trend analysis correlation analysis, and Hurst index. The results showed that the average annual NPP of vegetation in Qinghai Province gradually decreased from south to north and from east to west over the period 2000 to 2014, and that there were significant differences in the spatial distribution of each ecological region, as follows: area II > area I > area III > area IV > area V. From 2000-2014, the trends of NPP in Qinghai Province changed from north to south and from west to east, and the average trend coefficient was 15% of the total area, with a notable increase of 2.8% and a slight increase of 12.2% in the area of 0.61,NPP. The range of the Hurst index of NPP values in Qinghai Province was 0-0.39 and the mean value was 0.12; in addition to rivers and lakes, building land, and unused soil, the characteristics of NPP change in Qinghai Province were the characteristics of anti-persistence. Climatic factors (annual average precipitation and annual average temperature) had an impact on the distribution of the annual average NPP. The elevation results in differences in temperature, precipitation and soil, and indirectly affects vegetation NPP. Land use and cover change (LUCC) in 15 years showed that grassland area decreased the most, which was the main reason for the decrease in NPP.