在对1980年以来气候要素进行空间化的基础上,利用分类回归树模型CART计算中国的潜在归一化植被指数(NDVI),采用改进的光能利用率模型(CASA)和潜在NDVI数据对中国的潜在植被净初级生产力(NPP)进行模拟。结果表明:中国潜在NDVI和潜在NPP...在对1980年以来气候要素进行空间化的基础上,利用分类回归树模型CART计算中国的潜在归一化植被指数(NDVI),采用改进的光能利用率模型(CASA)和潜在NDVI数据对中国的潜在植被净初级生产力(NPP)进行模拟。结果表明:中国潜在NDVI和潜在NPP均呈现出南高北低、东高西低的格局,低值多分布在沙漠、戈壁等干旱地带,高值多出现在低、中山平原区;400 mm等降水量线是潜在NDVI和潜在NPP高值与低值的分界线;全国潜在NDVI和潜在NPP的平均值分别为0.396和319.31 g C·m-2;夏季潜在NPP的平均值最大,其次是春季,冬季最小;依据潜在NPP与2015年现实NPP的差异,可将中国植被恢复区划分为西部高潜力区、北部低潜力区和南部非潜力区3部分;潜在NDVI和潜在NPP的空间模拟可以将人类活动对自然生态系统的直接影响与气候变化的影响分离,量化了外界压力下真实的生态状况和潜在生态状况的差异,为制定差别化的生态恢复对策提供了科学依据。展开更多
This paper investigated spatial structures of 3418 national protected areas(NPAs)grouped into 13 types using GIS and quantitative analysis,including point patterns,Ripley’s K function,hotspot clustering,quadrat analy...This paper investigated spatial structures of 3418 national protected areas(NPAs)grouped into 13 types using GIS and quantitative analysis,including point patterns,Ripley’s K function,hotspot clustering,quadrat analysis,and Gini coefficient.Spatial accessibility was calculated for all NPAs from matrix raster data using cost weighted distance on the Arc GIS platform.The results are as follows:(1)The NNI of NPAs is 0.515,Gini is 0.073,all of which indicates distribution was shown to be a spatially dependent agglomeration,and more balanced in the provinces.The national key parks and the national water conservancy scenic spots had present the strongest aggregation,with NNI of 0.563 and 0.561 respectively,and K index indicates reducing aggregation when distance exceeds 600 km.(2)The national forest parks account for the largest proportion of 22.87% of all NPAs,and the world biosphere reserves the least of 0.77%.The number of NPAs in Shandong with 240 had been the largest one in all the provinces,while Tianjin had the least number including 9 NPAs.(3)There is only one hot spot in the first-class zone,5 in the second-class zones,and 51 in the third-class zones,which indicates NPAs are also aggregated at microscopic scales.(4)The hotspot NPA regions were mainly concentrated in the middle and lower reaches of the Yellow and Yangtze rivers,east of 100°E.High density of NPAs were generally in flat,water-rich,broad-leaved forest dominated plains and low mountain areas,with fertile soil,pleasant weather,long cultural history,and high transportation accessibility.(5)Average NPA accessible time is 60.05 min,with 70.76%regions being within 60 min,and the furthest was 777 min.The distribution of accessibility was positively related to the traffic lines.Interdepartmental protectionism has meant the various departments developed different management systems,standards,and technical specifications.展开更多
文摘在对1980年以来气候要素进行空间化的基础上,利用分类回归树模型CART计算中国的潜在归一化植被指数(NDVI),采用改进的光能利用率模型(CASA)和潜在NDVI数据对中国的潜在植被净初级生产力(NPP)进行模拟。结果表明:中国潜在NDVI和潜在NPP均呈现出南高北低、东高西低的格局,低值多分布在沙漠、戈壁等干旱地带,高值多出现在低、中山平原区;400 mm等降水量线是潜在NDVI和潜在NPP高值与低值的分界线;全国潜在NDVI和潜在NPP的平均值分别为0.396和319.31 g C·m-2;夏季潜在NPP的平均值最大,其次是春季,冬季最小;依据潜在NPP与2015年现实NPP的差异,可将中国植被恢复区划分为西部高潜力区、北部低潜力区和南部非潜力区3部分;潜在NDVI和潜在NPP的空间模拟可以将人类活动对自然生态系统的直接影响与气候变化的影响分离,量化了外界压力下真实的生态状况和潜在生态状况的差异,为制定差别化的生态恢复对策提供了科学依据。
基金National Natural Science Foundation of China,No.41661025Scientific Research Foundation for Universities of Gansu Province,No.2016A-001Research Capacity Promotion Program for Young Teachers of Northwest Normal University,No.NWNU-LKQN-16-7
文摘This paper investigated spatial structures of 3418 national protected areas(NPAs)grouped into 13 types using GIS and quantitative analysis,including point patterns,Ripley’s K function,hotspot clustering,quadrat analysis,and Gini coefficient.Spatial accessibility was calculated for all NPAs from matrix raster data using cost weighted distance on the Arc GIS platform.The results are as follows:(1)The NNI of NPAs is 0.515,Gini is 0.073,all of which indicates distribution was shown to be a spatially dependent agglomeration,and more balanced in the provinces.The national key parks and the national water conservancy scenic spots had present the strongest aggregation,with NNI of 0.563 and 0.561 respectively,and K index indicates reducing aggregation when distance exceeds 600 km.(2)The national forest parks account for the largest proportion of 22.87% of all NPAs,and the world biosphere reserves the least of 0.77%.The number of NPAs in Shandong with 240 had been the largest one in all the provinces,while Tianjin had the least number including 9 NPAs.(3)There is only one hot spot in the first-class zone,5 in the second-class zones,and 51 in the third-class zones,which indicates NPAs are also aggregated at microscopic scales.(4)The hotspot NPA regions were mainly concentrated in the middle and lower reaches of the Yellow and Yangtze rivers,east of 100°E.High density of NPAs were generally in flat,water-rich,broad-leaved forest dominated plains and low mountain areas,with fertile soil,pleasant weather,long cultural history,and high transportation accessibility.(5)Average NPA accessible time is 60.05 min,with 70.76%regions being within 60 min,and the furthest was 777 min.The distribution of accessibility was positively related to the traffic lines.Interdepartmental protectionism has meant the various departments developed different management systems,standards,and technical specifications.