Abstract
One of the quantities of interest in a spaceborne weather radar is the rain rate or liquid water content as a function of height. In the presence of attenuation, however, the reconstruction of the profile is possible with usual methods only if the rain rate is uniform or if the relationships between the radar measurables and the rain characteristics are well known. Even with a dual-wavelength radar, estimates of attenuation between adjacent range gates tend to be noisy. In this paper we investigate a class of methods that are based on a measure of path attenuation which is used to constrain the Hitschfeld-Bordan solution. Methods of this type have been investigated for lidar, radar, and combined radar-radiometer applications; their function can be interpreted as allocating the attenuation in proportion to the strength of the measured reflectivity. Four estimates of rain rate are described and tested using data from a dual-wavelength airborne radar at 10 GHz and 35 GHz. When attenuation is significant, the estimates are generally more accurate than those without attenuation correction. This suggests that such methods can be used to extend the effective dynamic range of the radar to higher rain rates. Comparisons between the estimates also provide some diagnostic capability for the detection of radar calibration errors. Instabilities in the estimates can occur, however, in cases of low signal to noise ratios and in situations where partially melted hydrometeors contribute to the attenuation.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have