| NPP is the solar energy fixed by vegetation during photosynthesis which can bedescribed as the net increase in biomass per unit time per unit area. The estimation of NPP,which plays an important part in the terrestrial carbon cycle research, not only can directlyresponse the generation capacity of the terrestrial vegetation in natural conditions, butdetermine the role of ecosystem carbon restore. And it’s an important factor to measureecological system adjustment ability. The CASA model is efficiency for solar energyutilization based on the remote sensing data combined with climate and vegetationinformation data to widely estimate the NPP value of vegetation, thus it plays a growing rolein the study of vegetation productivity.The thesis based on the theory of CASA model, using the GIMMS-NDVI data,meteorological data and the vegetation types data as the data source, improve the CASAmodel. It’s programmed by MATLAB and the NPP estimation according to the change of timeand vegetation types were studied. The thesis includes the following main contents:1. The research data have the feature of multi-source data, mainly including:GIMMS-NDVI data, climate and vegetation type data. It’s a main job to unify the format ofthe multi-source data for the estimation.2. CASA model and its improved method are introduced and estimating the NPP value inthe study area was based on MATLAB.3. The NPP data sets in the study area are built according to the estimation results and thecorresponding statistical data sets are created. From the perspective of the seasonal and annualchanges, the trend of the change of NPP was analyzed. At the same time, combined with theterrain and climatic features in the study area, the NPP among the variable types of vegetationwas compared. |
