IMPROVEMENTS IN NIMBUS-7 LIMB INFRARED MONITOR OF THE STRATOSPHERE OZONE PROFILES AS OBTAINED WITH UPDATED SPECTRAL-LINE PARAMETERS AND RADIANCE ALGORITHMS

Ozone distributions from the Nimbus 7 Limb Infrared Monitor of the Str atosphere (LIMS) experiment of 1978-1979 are generally in good agreeme nt with other concurrent ozone measurements in, the middle and upper s tratosphere, but not at lower altitudes. LIMS ozone is too large below about the 15-hPa (or millibar) level, particularly at lower latitudes . A new LIMS ozone distribution is presented for 1 day of profiles, Ma y 5, 1979, obtained with an improved forward radiance algorithm and us ing the spectral line parameters for the 9- to 10-mu m region in the H ITRAN 92 compilation. However, we also divided our single day of retri eved ozone mixing ratio profiles by a suggested factor of 1.051, which makes them compatible with the ozone distributions from several of th e UARS experiments. Our revised distribution still agrees with the arc hived LIMS ozone to better than +/- 5% above about the 15-hPa level, b ut there is a significant decrease for the revised ozone in the lower stratosphere. That decrease approaches 25% at 50 hPa in the tropics. I n general, the revised LIMS ozone is now in accord with the comparison data sets for the stratosphere, except for the lowest levels (Umkehr layer 3 or 63-127 hPa), where the effects of interfering species and s mall biases in LIMS temperatures are most pronounced. It is concluded that the current 9- to 10-mu m ozone line list is adequate for obtaini ng good quality ozone mixing ratio profiles from satellite broadband l imb-infrared measurements.