A comparative study of stratospheric temperatures between ILAS-II and other data

摘要

The successor of the Improved Limb Atmospheric Spectrometer (ILAS), ILAS-II, aboard the Advanced Earth Observing Satellite-II (ADEOS-II) measured atmospheric absorption spectra at a wavelength region from 753 nm to 784 nm, including the molecular oxygen (O2) A-band centered at 762 nm, with a FWHM spectral resolution of 0.06 nm. Temperature and pressure profiles between ~10 km and 80 km were retrieved from the solar occultation measurements of the O2 A-band spectra during the operational period of ADEOS-II in 2003. Based on the actual measured data during the smallest atmospheric variability, the repeatability of the measurement, which is a measure of the measurement precision, for temperature and pressure was estimated to be 1-2 K and 0.5-2%, respectively. Comparisons between ILAS-II and the U.K. Met. Office (UKMO) stratospheric analyses or the NASA's UARS/HALOE and TIMED/SABER temperature data are performed. Regardless of the good precision, it is found that the ILAS-II temperatures are systematically lower in the stratosphere and significantly higher in the lower mesosphere.