Relationship between inter-annual variations of microwave land surface emissivity and climate factors over the desert

Abstract

Microwave land surface emissivity of the Taklimakan Desert was retrieved based on AMSR- E( advanced microwave scanning radiometer-earth observing system) Leval 2A measurements and land surface and atmosphere products from GDAS( global data assimilation system) in 2008 under clear atmospheric conditions.Then,the spectral characteristics of the retrieved emissivity were classified and analyzed with respect to the soil types,and the relationships between desert emissivity annual variability and climate factors were also analyzed. The analyses indicate that the desert microwave emissivity and its annual variability are closely related to soil types.Moreover,there is a significant correlation between soil volume water content as well as land skin temperature and inter- annual variations of emissivity,which decreases with both of the two land surface parameters. Furthermore,vegetation coverage,canopy water content and surface roughness depending on the soil moisture are also the influencing factors of emissivity,and the soil moisture is restricted by both the atmospheric total precipitable water and the underlying soil type. Additionally,the surface emissivity of the desert mostly composed of sand observably decreases with the desert depth.