Figure 1. The SSM/I scan geometry, reproduced from Hollinger [1989]. For the 85 GHz channels there are two scans (Scan A and Scan B) for every one scan of the 37, 22, and 19 GHz channels. With twice the number of scans and twice the sampling rate, the 85 GHz channels have four pixels for each pixel in the 37, 22, and 19 GHZ channels.