Diurnal change of Amazon rain forest σ0 observed by Ku-band spaceborne radar

A Ku-band precipitation radar on the Tropical Rainfall Measuring Mission satellite provides backscattering coefficients (σ⁰) of Earth surfaces. The data are used to investigate σ⁰ characteristics of rain forest, and they show unique dependence on incidence angles and little dependence on seasons. A diurnal cycle is found in σ⁰ of the Amazon rain forest, showing the maximum σ⁰ in the morning and the minimum in the evening. It is inferred that the diurnal cycle is caused by dew drops on the leaves in the forests, and discussion on the dew effects with a simple model follows.