RAL Retrievals (Reported by VJ)
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Richard Siddans making good progress on joint MIPAS/GOME retrievals
of O3 (using MIPAS to retrieve stratospheric component).
EGS poster being prepared.
REC Analysis (AD/VP)
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(AD) Performing REC analysis on 7 months ESA L2 data (Aug-Feb)
for MIPAS Cal/Val report.
Plots from report for H2O, NO2 and Spectral Shift
- H2O continues to be a problem: H2O signature in non-H2O microwindows
suggest atmospheric concentration should be even higher than
retrieved (retrieval already thought to be too high).
- NO2 also identified as anomalous by Astrid Bracher (U.Bremen) in
comparison with HALOE and SAGE II (allowing for SZA variationa).
Residuals in NO2 microwindows show clear diurnal signature - could
the retrieval be too tightly constrained to the initial guess profile?
(eg not enough iterations?)
- Spectral Shift problem corrected in Nov 13th update - slope in fit
of 1st derivative spectrum disappears from November onwards
(VP) Simulated full MIPAS spectrum for Orbit 2081 Profile#68
(AMIL2DA mid-lat nighttime case) using OPTIMO-retrieved profiles.
- Retrieved H2O at this altitude about 6ppmv (cf expected 5ppmv, so 20%
too high).
- Plot showing Least Squares Fit of H2O residual
signatures in each 10cm-1 interval shows no evident disagreement
- Fit coefficient of 1 corresponds to about 10% difference in VMR (eg +1
implies that retrieved VMR is underestimated by 10%) but most
spectral regions have residual H2O signatures smaller than this with no
obvious bias (unlike results noted above).
- Probably need to repeat this exercise for different altitudes and
latitudes.
