Global vegetation dynamic monitoring using multiple satellite observations, 2002–2007

The backscatter values of altimeter and scatterometer have been investigated for possible use over land surface, especially for vegetation covered area. The spatial and temporal variations of backscatter coefficient of merged altimeter data (JASON1/ ENVISAT RA2), QuikSCAT, and CYCLOPES Leaf Area Index (LAI) over seven selected vegetated areas from 2002 to 2007 are calculated and compared. Initial results indicated that over vegetated areas with a strong seasonal cycle, the altimeter and scatterometer SigmaO measurements are strongly correlated to LAI. The Linear relation between VV/HH QuikSCAT backscatter and LAI is found at short and sparse vegetation, which is not valid at the dense vegetation. The VV/HH is not sensitive to low LAI value. The altimeter and scatterometer backscatter measurements of Ku band are useful to monitor vegetation dynamics as an independent data source compared to the products of optical sensors.