基于CASA模型的龙门山区域NPP时空格局分析

Analysis of Spatial Pattern of NPP in Longmen Mountains Area Based on CASA Model

以CASA模型为研究基础,以龙门山区域为研究对象,在ArcGIS和ENVI等软件的支持下,利用2017年的MODIS数据、植被类型数据和气象数据,估算龙门山区域NPP值,并分析NPP时空格局特征.结果表明:(1)龙门山区域2017年植被NPP最大值为1921g C·m^-2,年均为523g C·m^-2;(2)在时间格局上,植被NPP与气温、降水和NDVI具有明显的正相关性,最高为7月964g C·m^-2,最低为12月198g C·m^-2,且春、夏和秋季的NPP明显高于冬季;(3)在空间格局上,整体呈现出由区域南北两侧向中部递减的趋势.

Based on the CASA model and with the support of ArcGIS and ENVI software,this paper takes advantage of the 2017 MODIS data,vegetation type data and meteorological data to estimate net primary productivity(NPP)as well as analyze the distribution characteristics of spatial pattern of NPP in Longmen Mountain area.The results show that:(1)The maximum NPP of vegetation in Longmen Mountains area in 2017 is 1921 gC·m^-2,the annual average is 523 gC·m^-2.(2)In terms of time pattern,NPP has a significantly positive correlation with temperature,precipitation and NDVI,which shows a maximum of 964 gC·m^-2 in July,a lowest of 198 gC·m^-2 in December,and the NPPs in the seasons of spring,summer and autumn is obviously higher than in winter.(3)In the spatial pattern,the values of NPP diminish from both sides of the North and South to Central region.Due to better hydrothermal conditions in the northern and southern regions,the vegetation grows vigorously,and the NPP is mostly greater than 873 gC·m^-2;while the NPP value in the central and western regions is about 338 gC·m^2 lower than the value in northern and southern regions.However,since towns and population distribution in the eastern region is more focused,the NPP value mostly varies between 617 gC·m^-2 and 873 gC·m^-2.