Prior to EPIC leg1, it was discovered that the antenna pedastal and the INU were not in alignment. Grant Gray and Bob Bowie went to Seattle (where the ship was docked) to work on adjusting the INU in August 2001, several days before the ship left for San Francisco and San Diego. A summary of their work as well as an overview of Grant's attempt to perform a sphere calibration while the ship was en-route to San Francisco can be found here. A description of the procedure to collect and analyze the sphere calibration data can be found here.
During the EPIC campaign, Z-auto (internal calibration) and solar checks were used to monitor the C-band radar calibration and pointing angles.
After the completion of the experiment, comparisons of the C-band radar and the TRMM Precipitation Radar (PR) were performed by Carlos Morales and Manos Anagnostou, following the methodology of Anagnostou et al (2001). The TRMM PR has a calibration drift of less than 1 dB (Kozu et al., 2000; Kawanishi et al., 1998; 2000). For five TRMM overpasses used in the comparison, the results show very good agreement between the two radar and suggest no apparent bias in the C-band reflectivity values.