Tuesday, 11 February 2003: 8:45 AM
Global atmospheric temperatures: Error estimates of AMSU/MSU v. 5.0
Deep layer atmospheric temperatures derived from microwave emissions have been observed from satellites since 1979. Two types of instruments (the Microwave Sounding Unit or MSU, and Advanced MSU or AMSU) on eleven spacecraft have supplied data for the 24-year time series. Merging AMSU data of slightly different frequencies than the original MSU to continue a homogeneous time series will be examined. Additionally, a new, non-linear adjustment for the diurnal drift (i.e. east-west spacecraft drift) has been applied and will be demonstrated. Extensive comparisons with radiosonde-simulated deep layer temperatures will be shown. In general, the two independent systems reveal exceptional agreement on time and space scales from monthly variations at the gridpoint level to decadal trends of the global average. For globally-averaged tropospheric values for example, correlations of annual anomalies are at least 0.94 (depending on comparison dataset) and trends agree to within +/- 0.04 C/decade.