PRODUCT/VERSION: URAP 1998  O3_DAY BASELINE STANDARD

DATA SOURCE: MLS (Version 4), HALOE (Version 18), and SAGE-II (Version 5.96) 

TIME PERIOD FOR AVERAGING OF DATA: April 1992 to March 1993

ALTITUDE RANGE: 100 mb to 0.1 mb

LATITUDE RANGE: 80S to 80N

DESCRIPTION:

The monthly mean O3 values below 1 mb for HALOE and SAGE were first 
smoothed and interpolated by annual and semi-annual cycles (Wang et
al., 1996). Final O3 baseline is then derived by averaging all three
measurments. MLS O3 data from 183 and 205 GHz channels are used for
altitudes above and below 1 mb, respectively. Due to limitation of
satellite orbit from HALOE and SAGE, only MLS data is used to provide
O3 distribution poleward of 56 degree latitude. An adjustment factor
is then applied to MLS O3 data to remove a small discontinuiity at
this latitude. MLS O3 data is not used below 46 mb, and SAGE O3 data
is not used below 68 mb. Detailed description can be found in a paper
being submitted to JGR.

The chief features of the data are:   
(1) All three instruments give similar distributions with agreement better
    than 10% over almost the entire region.

(2) Diurnal cycle of ozone in upper stratosphere and lower mesosphere is 
    defined better than in past.

(3) Lower stratosphere distribution is well defined.

(4) The evolution of ozone hole can be found in Southern Hemisphere Polar
    region. 

WARNINGS:

(1) Bad (or missing) data values are set to 999.0 if there are any.

(2) Interpolation was necessary at some latitudes; these data are flagged
    negative.

REFERENCES:
Wang et al., J. Geophys. Res., vol, 101, pp. 12495-12514 (1996)

CONTACTS
Originator: Ray H.J. Wang, Derek Cunnold
URAP co-ordinator: John Remedios