吉林省长时间序列陆地生态系统NPP时空变化特征

植被净初级生产力(NPP)是陆地生态系统碳循环过程中的重要组成部分,也是评价碳源/汇的重要环节。基于2001—2019年MODIS地表反射率数据(MOD09A1)、气温和日照时间资料,利用光能利用率模型估算了吉林省陆地生态系统NPP,采用趋势分析、空间变异性分析等方法,分析了吉林省陆地生态系统NPP的时空变化特征及其与气候因子的相关性。结果表明:(1)2001—2019年,吉林省植被NPP年均值与总量均成波动上升趋势,辖区内植被NPP总量表现为森林农田草地。(2)2001—2019年NPP分布表现出明显的空间差异性,大部分区域NPP呈现增加趋势,总体变异性稳定,但西北部区域NPP空间变异程度较大,与该地区施行退耕还林和治理草地退化、沙化、盐碱化有一定关联,植被恢复明显。(3)吉林省植被NPP与年均气温、年降水量的相关性存在一定的地域差异性,研究区大部分区域与气温呈正相关关系,小部分区域与降水量呈现出正相关。

Estimation and Spatial-Temporal Dynamics of Long-term Sequenced Vegetation Net Primary Productivity in Jilin Province

Net primary productivity (NPP) of vegetation is an important part of the ecosystem carbon cycle process, and also an important part of carbon source/sink. Based on MODIS reflectance data (MOD09A1), temperature and sunshine hours data from 2001 to 2019, this study used the light energy utilization model to estimate the NPP of the terrestrial ecosystem in Jilin Province, and analyzed the spatial-temporal dynamics of NPP and their correlation with climate factors using trend analysis and spatial variability analysis. The results showed that:(1) From 2001 to 2019, the annual average and total amount of vegetation NPP in Jilin Province fluctuated and increased. The total amount of vegetation NPP within the jurisdiction showed the following:forest>farmland>grassland. (2) The distribution of NPP from 2001 to 2019 showed obvious spatial differences. NPP in most regions showed an increasing trend, and the overall variability was stable. However, the degree of spatial variability of NPP in the northwest region was relatively larger. Grassland degradation, desertification, and salinization were related to a certain extent, and vegetation restoration was obvious. (3) The correlations between vegetation NPP and annual average temperature and annual precipitation in Jilin Province had certain regional differences. Most areas of the study area had a positive correlation with temperature, and a small part of the study area had a positive correlation with precipitation.