Characteristics of Stratospheric Water Vapor Revealed by SAGE II(version 6) and HALOE(version 19) Observations Covering 1994-1999

SAGE II (Stratospheric Aerosol and Gas Experiment II) and UARS/HALOE (Halogen Occultation Experiment) have provided multi-year data sets of stratospheric water vapor profiles with similar spatial sampling frequency and similar verical resolution. The purpose of this paper is to examine the characteristics of water vapor in the stratosphere revealed by SAGE II(version 6) and HALOE(version 19) using observations covering the overlapping period 1994-1999. An interim empirical correction for the systematic bias has been applied to the SAGE II data set before comparison. The proposed correction scheme is based on the relative differences between SAGE II version 6 and version 5.9 data sets for the period 1986-1990. Correction factors are assumed to vary with altitudes, latitudes and seasons but without temporal variations. Results will be presented to illustrate the consistent water vapor climatology in terms of seasonal zonal mean profiles, seasonal variations of the hygropause and the latitudinal variations at various pressure levels. Anticipated changes for the upcoming version 6.1 SAGE II water vapor data set will also be discussed.