Oxford MIPAS meeting#53
20 Apr 04

Present

• Oxford: Alastair Burgess, Anu Dudhia, Don Grainger, Vivienne Payne
• RAL: Victoria Jay

Instrument Status [Prev] [Next]

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

• Unavailable since 26th March due to mechanical problems.

L2 OFL Data [Prev] [Next]

In /home/crun/mipas/L2/2PODPA/ [Plots of profile locations]

• L2 OFL (off-line) data continues to be processed, most recently for Mar/Apr 2003 and Mar 2004.
• Software version 4.61 in use since 17 Mar 2004

L2 Anomalies [Prev] [Next]

Four particular anomalies identified at QWG#3

Altitude shift in pointing >33km from 8-16 Feb 2004

Still under investigation

Offset of exactly 1 second between NRT and OFL L2 profiles

Appears to have been fixed with v4.61, ie no difference observed between NRT and OFL data processed with v4.61 software

Variations in species concentrations at low latitudes, notably a systematic offset between 25-27 Feb

See Message from Roberta Mantovani

Error in profile counts assigned to L2 residual spectra

Supposedly fixed in v4.61 but still incorrect (Roberta Mantovani has been sent an example)

RAL Retrievals (VJ) [Prev] [Next]

Still working on trying to retrieve Temperature and pointing using RAL retrieval code

NH3 Retrievals (AB) [Prev] [Next]

• Using OPTIMO plus sequential estimation to deal with low S/N.
• Retrievable NH3 only at 6km.
• Comparing [results] averaged over 1 month with [chemical model]
• Seems to reproduce high NH3 expected over N.Hemisphere land masses in summer, but not low values expected in south polar region

OCS Retrievals (AB) [Next]

• Using OPTIMO in normal mode (independent retrievals).
• [Results] for Aug 2003 at different altitudes show strange minimum around S. Polar vortex - if real, is this due to descent? chemistry?

S6 Mode (AD) [Prev] [Next]

S6 mode is 0.1cm^-1 spectral resolution, 2km vertical resolution, 100km horizontal resolution

• Microwindow selection completed for key species and minor species
• Currently generating look-up tables and irregular grids

EGU, Nice, 25-30 April 2004 [Prev] [Next]

Website: http://www.copernicus.org/EGU/ga/egu04/programme/overview.html

Oral Presentation

• Retrievals of UT/LS O3 and H2O from MIPAS Observations (V. Jay) [PDF File]

ACVE-2, Frascati, 3-7 May 2004 [Prev] [Next]

Website: http://www.congrex.nl/04m01/

Planned abstracts (due April 25th)

• Comparison of MIPAS dataset with climatology (V. Payne)
• Differences between MIPAS NRT and Off-line products (A. Burgess)
• Comparisons of MIPAS and GOME O3 (RAL)

Quadrennial Ozone Symposium, Kos 01-08 Jun 2004

Website: http://www.qos2004.gr/

Extended abstracts (due 20th April)

• Retrieved Ozone from two years of MIPAS measurements (C. Piccolo)
• Ozone isotopic ratios from MIPAS limb emission spectra (C. Piccolo)
• Analysis of water vapour and methane from the MIPAS satellite instrument (V. Payne)
• Retrievals of isotopic ratios of water vapour and methane from the MIPAS satellite instrument (V. Payne)
• Sounding Tropospheric Ozone from Space through Synergistic Use of Limb IR Emission and Nadir UV Backscatter Observations (RAL)

COSPAR, Paris, 18-25 Jul 2004

Website: http://www.copernicus.org/COSPAR/COSPAR.html

Submitted abstracts (due February 29th)

• Retrieval of Upper Tropospheric Ammonia from MIPAS/Envisat (A. Burgess)

Envisat & ERS Symposium, Salzburg 6-10 Sep 2004 [Next]

Website: http://www.congrex.nl/04a06/

Submitted abstracts (due April 15th)

• MIPAS Microwindows (A. Dudhia)
• Water vapour isotope measurements: comparisons between results from MIPAS and the Odin SMR (V. Payne)
• Analysis of water vapour and methane from the MIPAS satellite instrument (V. Payne)
• Retrieval of Sulphur-containing Atmospheric Constituents from MIPAS/Envisat (A. Burgess)
• Retrievals of O3 and H2O in the lower stratosphere and troposphere from Envisat (RAL)

I have analysed the gain calibration during February and the beginning of March.

For NRT processing only one gain has been disseminated in February with start validity 20040205 13:47:26 (orbit processed for gain generation: 10067, dated 20040202).

An instrument decontamination has been done from 2 February to 8 February, so the gain after the decontamination has not been updated for NRT processing.

For OFL processing the gain measurements have been processed later and the attached plot shows that excluding the strong gain decrease caused by the decontamination, the general trend is characterized by an increase below 1% per week for both February and the beginning of March.

My conclusions are:

• I don't see any correlation between gain calibration and temperature increase occurred from 27 to 29 February.
• The CH4 and N2O trend can be explained by the gain increase and by the fact that for NRT processing the gain has not been updated.
• I don't see any correlation between gain calibration and the jump observed at the beginning of March for CH4 and N2O.