Observing the land with radiometer

the land parameters

such as soil moisture

soil roughness and vegetation layer

have great influences on the soil microwave emission.Calibration for the soil roughness parameters is very important for land surface parameters retrieval with radiometer.Soil roughness parameters（h and Q） vary with the observing frequency.In the past studies

h was considered to vary in the world and Q was considered to be a fixed value.Then

usually

h was assigned to zero and Q was derived over desert.In fact

both h and Q are affected by the land surface conditions and vary globally.This paper takes AMSR-E data as sample data and presents a new parameter Γ

which is computed from MPDI and independent on the soil moisture.Γ is dependent on soil roughness and vegetation water content

and it has the potential to calibrate the soil roughness parameters and estimate the vegetation water content

vegetation growth/variety.In this paper

Γ is used to calibrate soil roughness parameters over the desert in the north of Africa

and the calibration results are compared with the results from the past studies.