Pressure and Temperature Retrieval using Oxygen A Band in Solar Occultation Measurement with Improved Limb Atmospheric Spectrometer (ILAS)

Abstract

It has been well recognized that the temperature and pressure determination is important to the remote sensing of atmosphere. Currently, most limb viewing instruments, such as LIMS, IS AMS, and HALOE, have been using infrared CO2band for the pressure retrieval because of its uniform mixing ratio through troposphere to stratosphere. Molecular oxygen, which has well established spectrum and has extremely uniform mixing ratio in the atmosphere, could give better pressure information compared with the CO2. Matsuzaki et al.[1] have reported the rocket experiment to observe the oxygen A band, where they showed that the rotational spectrum could give the mean temperature of a slant path in a precision as low as 1.5 K. Considering the size of visible spectrometer, it is very valuable to build the IR solar occultation instrument with a visible spectrometer for the temperature and pressure retrieval, because the better pressure and temperature give more accurate vertical profilde of the target gases in the IR channel. This paper presents the pressure and temperature retrieval using Oxygen A band for a solar occultation measurement by Improved Limb Atmospheric Spectrometer(ILAS) aboard ADEOS spacecraft which will be launched in early 1995.