An Investigation of Degradation Errors in Tiros IV Scanning Radiometer Data and the Determination of Correction Factors

摘要

The degradation errors in the TIROS IV scanning radiometer data of reflected solar radiation (channel 3) and emitted long-wave radiation (Channel 2) are discussed and correction factors are derived. For the reflected solar radiation measurements, a correction factor was obtained by comparisons with aircraft albedo measurements under cloudless conditions. The results for channel 3 are compared with ballon-flight measurements and other studies. For the channel 2 data, the correction factor was obtained from a comparison of daily average values of outgoing long-wave radiation with the average value on the first day after launch. Variations in the daily averages of outgoing long-wave radiation for the area bounded by 55 degrees N and 55 degrees S latitudes are compared with variations in the average values at individual points. The correction factors obtained for both channels give reasonable results when applied to individual grid points, but when the corrected values are summarized over the entire field of data they yield quasi-global averages which appear to be too low if radiative equilibrium is assumed. (Author)