NIMBUS 3 “SIRS” PRESSURE HEIGHT PROFILES AS COMPARED TO RADIOSONDES

Abstract

Tropospheric height and thickness values derived from Nimbus 3 Satellite Infra-Red Spectrometer (SIRS) sounding data are compared with nearby radiosonde data to determine (a) the accuracy and compatibility of SIRS data relative to the radiosonde and (b) the utility of SIRS data relative to the radiosonde, for objective analysis. The study shows that both the relative accuracy and the utility of the SIRS data are strongly dependent on cloud conditions, pressure level, and instrument status. SIRS thickness values in the upper troposphere compare well with radiosonde data. Loss of the 714 cm?1 channel in November 1969 greatly reduced the quality of the SIRS data, especially at lower levels; but prior to the loss, clear-air soundings show approximate parity with radiosonde observations.