【摘要】 为了明确区域植被固碳能力与地形因子的关系以及掌握区域长时间序列下净初级生产力(NPP)的时空分布特征,以2000—2015年MOD17A3的植被NPP数据及地形因子DEM数据为基础,辅以回归分析及分级统计等方法,利用GIS技术定量剖析了重庆市作为典型山地区域近16年植被NPP的时空变化特征,研究了地形因子(高程、坡度)与植被NPP的相关性。结果表明:(1) 2000—2015年重庆市植被NPP整体呈东南部高,西北部低的分布态势,其中,长江以南区域植被NPP差异明显,由南向北递减,总体高于长江以北的区域。(2) 16年间,重庆市植被NPP年际均值在481.512～658.557 g C/(m~2·a)浮动,其中,处于500～600 g C/(m~2·a)的占比最大,其次是600～700 g C/(m~2·a)。2000年与2015年相比,整体呈正增长的变化趋势。(3)分别对高程和坡度进行了等级划分,分析可得重庆市平均植被NPP随海拔和坡度的升高有明显的先升高后降低的趋势,在高程500～1 000 m、坡度15°～25°的区域NPP达到峰值。(4)植被NPP先增后减的倒"V"型变化模式在一定程度上反映了高程、坡度处于某临界点时,气候、降水、植被分布、坡面侵蚀强度等因素对植被NPP影响更加显著。研究结果可为重庆地区植被碳储量状况以及生态环境调节与修复提供理论与数据支持。更多还原

【Abstract】 In order to clarify the relationship between carbon sequestration capacity of regional vegetation and topographic factors, and to grasp the spatial and temporal distribution characteristics of primary productivity through regional long time series, based on the vegetation NPP data of MOD17 A3 and DEM data of topographic factors from 2000 to 2015, with the help of regression analysis and grading statistics, the spatial and temporal variation characteristics of vegetation NPP in Chongqing City as a typical mountainous area in recent 16 years were analyzed quantitatively by using GIS technology, and the correlation between topographic factors(elevation, slope) and vegetation NPP was studied. The results showed that:(1) from 2000 to 2015, the vegetation NPP in Chongqing City was high in the southeast and low in the northwest; the difference of vegetation NPP in the south of the Yangtze River was obvious, and it decreased from south to north, which was higher than that in the north of the Yangtze River;(2) during 16 years, the annual mean NPP of vegetation in Chongqing City fluctuated between 481.512～658.557 g C/(m~2·a), of which 500～600 g C/(m~2·a) accounted for the largest proportion, followed by 600～700 g C/(m~2·a), compared with 2015 and 2000, the annual mean NPP of vegetation presented the increasing trend;(3) the elevation and slope were classified, and the analysis showed that the average vegetation NPP in Chongqing City increased firstly and then decreased with the increase of elevation and slope, and reached the peak value in the areas with elevations of 500～1000 m and slopes with 15°～25°;(4) the inverted ‘V’ pattern of vegetation NPP with increase first and then decrease to some extent reflects that when elevation and slope are at a critical point, climate, precipitation, vegetation distribution, slope erosion intensity and other factors have more significant impacts on vegetation NPP. These results can provide theoretical and data support for the status of vegetation carbon storage and the regulation and restoration of ecological environment in Chongqing City.更多还原