SMART-R/S-Pol Reflectivity Comparisons and Attenuation Corrections during DYNAMO

Two radars were operated in close proximity on the Addu Atoll during the DYNAMO field experiment: the Texas A&M SMART-R C-band system and the NCAR/NSF S-PolKa radar. The two radars varied considerably in wavelength, update frequency, beam width, and other characteristics. As with any project using multiple radars, the issue of radar inter-comparison and calibration accuracy needs to be considered. Of particular interest is the re-evaluation of C-band attenuation in the tropical atmosphere. The near co-location of the S-band radar with the C-band permits good comparison of reflectivity, and, since the S-band is largely non-attenuated, provides an opportunity to determine the coefficients for the attenuation-rain rate equation, based upon multi-case minimization of error between the two radars.

Results are first presented for a reflectivity comparison using the GATE (1976) experiment attenuation equation. Afterward, these results are compared to determinations using the same form of the equation, but with the new coefficients. It is proposed that the adjusted coefficients can then be used to adjust the reflectivity of the other C-band radars used during DYNAMO.