Ozone monitoring with TIROS-N operational vertical sounders

The potential for using the TIROS-N operational vertical sounder (TOVS) on NOAA polar-orbiting weather satellites to monitor stratospheric ozone is examined. TOVS 9.7-mu m high resolution infrared sounder (HIRS) ozone channel is found to be particularly well suited for monitoring the lower stratospheric ozone layer. A 3 Dobson unit drop in lower stratospheric ozone produces a measurable (i.e., approximate to 0.2 degrees C) increase in HIRS 9.7-mu m brightness temperatures even in the vicinity of Antarctica. A two-layer physical retrieval algorithm is presented that uses the TOVS HIRS 9.7-mu m signal to determine lower stratospheric ozone and to estimate total ozone. Trend analysis of TOVS ozone confirms the fact that there have been significant losses of lower stratospheric ozone in the spring equinox extratropics of both hemispheres. Much of this loss persists into the summer solstice time period.