This presentation is a progress report on our program to develop a trend-quality temperature data set for the middle and upper stratosphere by establishing data continuity between the Stratospheric Sounding Unit (SSU) and the Advanced Microwave Sounding Unit (AMSU) on the NOAA operational meteorological satellites. The AMSU instrument on the NOAA-15 polar orbiting environmental satellite became operational in June 1998, replacing the SSU for stratospheric temperature soundings. AMSU instruments are scheduled to operate on all NOAA polar satellites for at least the next 10 years. AMSU provides radiometric information from 12 channels, 6 of which have peak sensitivity in the stratosphere. The AMSU channel which peaks near 70 hPa in the lower stratosphere is the same as channel 4 on the Microwave Sounding Unit (MSU) instruments, which have been operating on NOAA polar satellites since 1979. The new AMSU stratospheric channels, not available on MSU instruments, have weighting functions that peak sharply near 1.5, 4, 8,15 and 30 hPa. SSU instruments have operated on 6 of the NOAA polar satellites since 1979, providing a continuous time series of data in three broad-peaked stratospheric channels, with maximum weighting near 1.5-, 5-, and 15- hPa. Using off-nadir measurements, additional channel information has been derived (by Nash, UK Meteorological Office) providing information at 0.5-, 2-, 6-, 20-, and 50- hPa.

Our goal is two-fold: 1. Through comparison of the separate SSU and AMSU data during overlap periods we will establish a cohesive brightness temperature data set for each instrument 2. Through statistical regression methods we will develop a method to simulate SSU brightness temperatures from the AMSU radiances

Utilizing this methodology, we will develop a “trend-quality” stratospheric temperature data set suitable for studies of ozone change/recovery and climate change.