The Study On Estimation Of NPP And Biomass Of Vegetation In Qira Oasis Based On RS And GIS

Net primary productivity (NPP) is defined as the difference between accumulative photosynthesis and accumulative autotrophic respiration by green plants per unit time and space. Biomass is defined as the total weight of dry matter that includes all biological organism per space in certain time. Both are two aspects of vegetation productivity. With the rapid development of RS, GIS and cyber-technology, the study by using remote sensing for NPP hastens maturely. By means of remote sensing model, it can monitor fast NPP of vegetation in a large scale and evaluate the productivity of the plant community in natural environment. The study is estimation of NPP and Biomass. Based on geographical and ecological knowledge, support of RS and GIS, using NPP models of light energy utilization and Biomass RS Stat-model, it gets NPP and Biomass in May and July. The aim is to analyse quantitatively, estimate and monitor productivity in Qira. This dissertation includes following parts: 1)Measure about the character of vegetation spectrum and complementarity of earth surface object's spectrum database. So, measure about the character of vegetation spectrum is basic works of this thesis. 2)The threshold value both desert and oasis is 2.7912 in this study.The pixels of ≥2.7912 are merged in oasis. Others are merged in desert. 3)Estimation of NPP and Biomass. NPP total 4.7865×10~9g/d in May and 8.7263×10~9g/d in July. Biomass total 2.0865×10~11 g in May and 2.2908×10~11 g in July. 4)In Qira oasis, NPP and Biomass of five landscapes increase in turn: desert and water