Retrievals of Stratospheric Retrievals of Stratospheric Ozone Density Profiles from Ozone Density Profiles from Odin/OSIRIS Limb-Scatter Odin/OSIRIS Limb-Scatter

MeasurementsMeasurements

C.S. HaleyC.S. HaleyYork UniversityYork University

S.V. PetelinaS.V. PetelinaUniversity of SaskatchewanUniversity of Saskatchewan

and the OSIRIS Teamand the OSIRIS Team

Step 1: Normalization of limb radiance profiles

ref

iin THλ,I

THλ,ITHλ,I with THi being the ith tangent height,

THref reference tangent height

Reduction of the impact of albedo on limb radiance profiles

Step 2: Combination of wavelengths

• Employ the Chappuis absorption bands of O3, and define the Chappuis retrieval vector yC(TH) by

inin

iniC

THnm,672lnITHnm,532lnI21

exp

THnm,602ITHy

Method

OS Limb Scan

xn+1 = x0 + SxKnT[KnSxKn

T + S] -1 (y - yn - Kn(x0-xn))

S = Sx - SxKT[KSxKT + S]-1 KSx

x0: ln of a priori O3 profile xn: ln of nth estimatey: ln of measured Chappuis retrieval vectoryn: ln of modelled Chappuis retrieval vector for xn

Sx: covariance matrix of a priori S: covariance matrix of measurement yK: Weighting function matrix

dunperturbeperturbed

dunperturbeperturbed

n3n3

mcmcmn

zOlnzOln

THlnyTHlnyK

Optimal Estimation

Forward model is LIMBTRAN [Griffioen and Oikarinen, 2000]

• Pseudo-spherical: SS treated in spherical shell atmosphere Diffuse radiance source functions calculated in 1-D plane parallel atmosphere applying the finite differences method.• Variation of SZA and along LOS.

OS and TOMS ozone column daily maps

25 February 2002

OS – POAM ComparisonsOS – POAM Comparisons

OS – POAM ComparisonsOS – POAM Comparisons

OS – POAM ComparisonsOS – POAM ComparisonsNovember 2001

OS – POAM ComparisonsOS – POAM ComparisonsFebruary 2002

OS – POAM ComparisonsOS – POAM ComparisonsDecember 2001

OS – POAM ComparisonsOS – POAM ComparisonsJune 2002

OS-SAGE ComparisonsOS-SAGE ComparisonsNovember 2001

OS-SAGE ComparisonsOS-SAGE ComparisonsFebruary 2002

OS-SAGE ComparisonsOS-SAGE ComparisonsJune 2002

OS-SAGE ComparisonsOS-SAGE ComparisonsJuly 2002

OS-sonde ComparisonsOS-sonde Comparisons

OS-sonde ComparisonsOS-sonde Comparisons

Ozone hole split in September 2002

Ozone hole split in September 2002

Ozone hole split in September 2002

Ozone hole split in September 2002

Ozone hole split in September 2002

Future WorkFuture Work

• Good agreement between OSIRIS, POAM III & SAGE II

• Data is now being used in some preliminary assimilation studies and to evaluate other retrieval methods (DOAS, BIN, MOP)

• Apparent tangent height registration issues that need to be addressed

• Addition of UV wavelengths required to improve upper stratosphere retrievals – in progress