Oxford MIPAS meeting#77
21 Jun 05

Present

Oxford: Alastair Burgess, Anu Dudhia, Don Grainger, Chris Hepplewhite, Chiara Piccolo, Gareth Thomas, Claire Waymark.

Instrument Status [Prev] [Next]

Some details on the Envisat Web-Site including Instrument Availability web-site

Latest version of Mission Planning Document (from Marta de Laurentis) covering 1 Jan 05 to 11 Jul 05:

[MIPAS_Mission_Planning_2005_DRAFT.xls] (Excel spreadsheet)
[MIPAS_Mission_Planning_2005_DRAFT.html] (Converted to Web page)

Currently operating for 4-5 orbits per day with the nominal scan pattern to support the Teresina campaign (Brazil).

L2 OFL Data (CP) [Prev] [Next]

[Plots of profile locations]

v4.62 reprocessed data for late 2002 continues to arrive.
Starting to extract residuals for rerunning REC analyses (previously only performed on NRT data).

HiRDLS Comparisons (CW) [Prev] [Next]

Comparing integrated MIPAS and HiRDLS Radiances for 28th January 2005 in order to validate HiRDLS radiometric calibration.

Only 10 (rather than previously estimated 12) out of 21 HiRDLS Channels are completely covered by MIPAS bands so concentrate on these (others are longer wavelength or overlap the MIPAS band gaps).
Interpolate the HiRDLS filter responses to 0.0625cm-1 resolution for simple multiplication by MIPAS spectra.

2RR Microwindows (ie 0.0625cm-1 resln) (AD) [Prev] [Next]

Selecting microwindows for new nominal mode operations which employ floating altitude grid (lowest altitude 3-9km from pole-equator) and 1.5km spacing at lower altitudes

Microwindow selection, LUT & irregular grid generation completed for pT, CH4, N2O, NO2 and O3.
MW selection still in progress for H2O and HNO3
Three different selection criteria have been used, with up to 10 MWs selected for each:
- MW 300-310: Minimise Total Error (plotted in red)
- MW 311-320: Emphasis on reducing systematic component (green)
- MW 321-330: Emphasis on reducing total error below 21km (blue)
Original 0.025cm-1 off-line microwindows and error profiles also plotted in grey.
Plots generally show a significant improvement compared to the OFL data, but this improvement is concentrated at high altitude and simply attributable to using more microwindows (10 rather than 2 or 3).
However, useful accuracy appears attainable at 1.5km resolution at low altitude, probably using far fewer than 10 microwindows.

OCS (AB) [Prev] [Next]

Using MIPAS D-band microwindows to retrieve OCS

[Histogram plots] of OCS binned by altitude/lat/lon/season seem to show a secondary peak at low altitude over Africa and Indonesia, possibly indicative of biomass burning (but may also be related to cloud-contamination)
Unreasonable high antarctic winter OCS values appear not to be related to PSC contamination (ie no correlation with Cloud Index) but do seem to be related to using latitude-varying initial guess data - not yet established which field is causing the problem.

Data Assimilation (CP) [Prev] [Next]

DARC study to investigate method of removing a priori influence on retrieved O3 profiles by assimilating information rather than profiles.

DARC require detailed averaging kernels for every O3 OFL profile, so will generate these using the ORM for a few days to see if this makes any significant difference to the assimilation.
A better test might be to compare assimilations of MORSE profiles (ie optimal estimation, therefore with a more explicit a priori component) and their information, but MIPAS OFL data currently available.

Oxford MIPAS meeting#77 21 Jun 05

Oxford MIPAS meeting#77
21 Jun 05