Spatial-temporal Variations of Net Primary Productivity of Qilian Mountains Vegetation Based on CASA Model
By using the remote sensing data and the climate data of DEM elevation model calibrated in 2003 -2012,we estimated the net primary productivity(NPP) of Qilian Mountains vegetation based on CASA model.The years,annual variation of NPP,the temporal spatial distribution and change trend were also an alyzed.The results reveal that:(1)The NPP in Qilian Mountains is mainly concentrated during the summer (June to August),it accounts for 86.39％ of the total NPP;From 2003 to 2007,Minor fluctuations between 165.28 g· m-2 · a-1and 192.75 g · m-2 · a-1 in the annual average of NPP;NPP showed a significant downward trend from 2007 to 2009,by 168.63 g · m-2 · a-1 down to 153.17 g · m-2 · a-1;while,NPP showed a clear upward trend from 2009 to 2012,the maximum value can reach 207.13 g · m-2 · a-1.(2) The spatial distribution of NPP in Qilian Mountains showed a rising tendency from west to east.NPP in most of the eastern regions varied from 200 to 400 g · m-2 · a-1,in some areas up to 500 g · m-2 · a-1.There were obviously differences between the north and the south in the central region;NPP in most of the southern regions varied from 100 to 300 g· m-2 · a-1,but it varied from 100 to 400 g · m-2 · a-1in most northern regions.NPP in most of the western regions was between 0 and 100 g · m-2 · a-1,especially the desert and alpine ice snow covered area had the lowest biomass.(3)NPP in the Qilian Mountains has been increased volatility in the recent ten years;the area of NPP increased about 9 867 km2 and it accounts for a bout 21.19％ of the total area;the reduced account for 17.52％ of the total area about 8 173 km2.The re sults showed that the ecological health of Qilian Mountains is improving in the overall,although it deterio rated in the local.
NPPCASA modelspatial-temporal variationsQilian Mountains region
NETL
NSTL
万方数据
维普
