广西植被净初级生产力(NPP)时空演变及主要影响因素分析

Analyzing variation characteristics of vegetation net primary productivity(NPP)in Guangxi

关键词:  净初级生产力  喀斯特  气候  森林  广西

Key words:  net primary productivity  karst  climate  forest  Guangxi

摘要:

利用2001-2010年EOS/MODIS17A3卫星遥感资料,对广西植被净初级生产力(NPP)时空特征及其影响因素进行分析。结果表明:(1)NPP 表现出明显的年际变化,2005年植被年均NPP最小为625 gC·m^-2·a^-1,2003年最大,为714 gC·m^-2·a^-1,十年间广西植被年NPP平均值为662 gC·m^-2·a^-1;(2)不同植被类型NPP有较大差异,森林、灌木、农作物的NPP平均值分别为834、614、517 gC·m^-2·a^-1;(3)十年间广西区年均NPP为显著下降趋势,且年均气温和降水对NPP时间变化作用显著,而日照时数对NPP时间变化的作用不显著;(4)广西区NPP空间格局形成主要影响因素为坡度,其次为经度,再次为地貌特征、纬度和降水;(5)非喀斯特区域北热带季雨林、南亚热带季雨林化/季雨化常绿阔叶林年均NPP大于喀斯特地区,相反,喀斯特地区中亚热带常绿阔叶林,农作物年均NPP大于非喀斯特地区。整体而言,广西非喀斯特地区植被NPP为683 gC·m^-2·a^-1,喀斯特地区植被NPP为620 gC·m^-2·a^-1。

Abstract:

Using MOD17A3 data from EOS/MODIS,this article analyzed spatio-temporal characteristics of vegetation net primary productivity(NPP)in Guangxi. The results showed that NPP in 2005 had the lowest value(625 gC·m^-2·a^-1),while 2003 had the largest mean value(714 gC·m^-2·a^-1); and the average annual value of the vegetation NPP was 662 gC·m^-2·a^-1 from 2001 to 2010. The NPP value of different type vegetation showed great differences,for example,the NPP of forests,shrubs and crops was 834,614,517 gC·m^-2·a^-1 respectively. In this decade,annual NPP declined significantly,and the annual average temperature and precipitation had significant effect on NPP,the sunshine time had no significant effect on NPP time changing. The influencing factor of NPP spatial pattern was slope,following by longitude,again to topographical features,latitude,and precipitation. Annual NPP of tropical and subtropical forests and shrub in karst region during this ten years was less than those in non-karst region,but the forest and agricultural vegetation had the opposite trend. Overall,the vegetation NPP was 683 gC·m^-2·a^-1 in non-karst region and 620 gC·m^-2·a^-1 in karst region.