Analysis Of Vegetation Change And Influence Factors In The Yellow River Basin Based On Optical And Microwave Remote Sensing

The Yellow River basin has a vast territory,complex topography and geomorphology,the spatial and temporal distribution of vegetation covers a large difference,and there are many factors affecting the vegetation growth process.In this paper,the third generation of GIMMS NDVI data set,MODIS NDVI data set which based optical vegetation index data sat,and a new generation of microwave sensor AMSR2 data set based microwave vegetation index data set based on analysis of the variation characteristics of air and suitable vegetation in different vegetation index in the Yellow River basin cover,rainfall,temperature,drought and research the climate factor influence on vegetation growth process.The main research results and conclusions are as follows:?1?Analysis the applicability of optical vegetation index NDVI data sets and microwave vegetation index in the Yellow River basin vegetation monitoring results show that two vegetation indices reflecting the the Yellow River river long time series vegetation change trend both are pretty good,the changing trend of the microwave polarization difference index MPDI₁₈,MPDI_36.5 and optical vegetation index was NDVI significant positive correlation,the microwave vegetation penetration index MVI and optical vegetation index NDVI showed a significant negative correlation.the microwave polarization difference index MPDI_36.56.5 based on frequency 36.5 in the monitoring of vegetation change is better than the microwave polarization difference index MPDI₁₈8 based on frequency 18.?2?On the Yellow River river long time series vegetation spatial and temporal variation characteristics,the results show that the third generation of GIMMS NDVI data set has good effect in the study on spatiotemporal change of vegetation,vegetation change cycle significantly,and long time series of vegetation change is consistent with the actual situation;the MODIS NDVI data set also has a good effect on vegetation temporal and spatial variation monitoring in the Yellow River basin,the correlation of two data sets coefficient reached 0.95.Results show that the temporal and spatial variations of vegetation cover in the Yellow River River Basin was the overall growth trend,such as the Northern Shanbei plateau,Huangpuchuan,Kuye River,vegetation has obvious growth.The temporal and spatial variation of the length of vegetation in the source area of the Yellow River is not obvious,it has been maintained at about 0.6 for many years.At the same time,the data set of the microwave vegetation index is in good agreement with the spatial and temporal distribution characteristics of the optical vegetation index data set.?3?The relationship between the trend of vegetation growth and rainfall,temperature and drought in the Yellow River basin is analyzed.The results show that there is a positive correlation between vegetation and rainfall in the Yellow River basin,and the correlation coefficient is bigger.The response time of vegetation to rainfall is 1 months.There is a positive correlation between the vegetation and the temperature,and the response time of the vegetation to the temperature is 3 months.The correlation between vegetation index and microwave drought index TMVDI,TMPVDI and TMPVDI₁₈ based on Microwave vegetation index inversion is also North higher and South lower,what's more,the correlation between vegetation index and microwave drought index TMVDI is the best.This paper discusses the optical and microwave vegetation index data set used in the the Yellow River River Basin,analysis of spatial and temporal variation characteristics of vegetation cover in the Yellow River basin,and reveals the long time series vegetation spatial variation;analysis of vegetation in response to rainfall,temperature,drought,provide technical support for the long time series of vegetation index data sat spatial and temporal changes and influence facors analysis.