Oxford MIPAS meeting#64
26 Oct 04

Present

• Oxford: Alastair Burgess, Anu Dudhia, Don Grainger Vivienne Payne, Chiara Piccolo, Joanne Walker, Claire Waymark (D.Phil student)
• U.Bologna: Enzo Papandrea
• RAL: Martin Juckes

Instrument Status [Prev] [Next]

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

No news

L1 Data (CP) [Prev] [Next]

Reprocessed ("consolidated") ESA L1B data are starting to appear at BADC - see Message from BADC.

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

[Plots of profile locations]

• Reprocessed v4.62 now started to arrive (for days which have not been processed using v4.59 or 4.61), shown as yellow squares on the table of our local L2 archive
• v4.62 should fix the following problems
  1. Correct function of cloud-detection
  2. Error in profile count
  3. Negative variance values

H2O (VP) [Prev] [Next]

• Attempt to select microwindows which include the high altitude column uncertainty as part of the selection process (instead of being mapped in retrospectively) results in generally poor microwindows as all strong lines are excluded.
• Next plan is to try selecting H2O microwindows excluding the C band

MORSE (AD) [Prev] [Next]

MIPAS retrieval code being written at Oxford for public use, funded by NERC.

• Improved flexibility, eg allowing microwindows to be specified by a simple list, and multiple input files/directories
• Additional options added to allow output of covariance matrices and a priori

SF6 (AB) [Prev] [Next]

[Zonal mean plots] of retrievals of SF6 (using OPTIMO) show unrealistic minima at 9km at around +/-20deg N which appear to be related to temperature maxima. Under investigation

H2O2 (EP) [Prev] [Next]

Orbit 2081 retrieved (using MORSE)

• [H2O2]
• [O3]

Clear correlation with O3, as expected due to chemistry: (OH+O3) is a source of stratospheric H2O2, although values extend to higher altitudes than expected

Few other measurements of H2O2, so awaiting results from a run of the SLIMCAT model for comparison.

CH4 (VP) [Prev] [Next]

Trying to find origin of low tropical tropopause values.

• Using simulated data from an atmosphere at 1km resolution, MORSE shows some hint of an oscillation for the equatorial tropopause
• Next step: relax a priori to something which better simulates the ESA least-squares fit retrieval to see if oscillation resembles that of the ESA data
• (CP/EP) Will also run ORM with the same simulated data to check

CO2 (EP) [Prev] [Next]

Selecting microwindows for a joint retrieval of: pT+H2O+O3+CO2

• Previous attempt at selecting joint pT + CO2 microwindows showed accuracies only slightly better than 10% could be expected, due to difficulty in discrimination between pressure and CO2 Jacobians
• Including H2O and O3 seems to indicate accuracies of better than 5% may be achievable
• CO2 line mixing, horizontal gradients and spectroscopic database uncertainties have been excluded as error sources in this selection
• So far, selection restricted to A-band only (685-970) (for reasons of CPU time) but better results may be obtained if allowing selection to use all MIPAS bands

MIPAS Science Team Meeting#1 (AD) [Next]

Held at ESRIN, 6 Oct 2004.

Minutes (PDF) (from Claus Zehner, ESRIN).

O3 Isotopes (CP) [Prev] [Next]

Following a query from Gabi Stiller (IMK) it has been discovered that the error budgets for the O3 isotopic microwindow selection were a factor of 10 too small (due to isotopic jacobian perturbations of 10% rather than 1% being used in order to avoid numerical precision errors)

• Microwindows being reselected
• Following discussions with those retrieving O3 isotopic ratios from balloon experiments, selecting microwindows for a joint retrieval of the symmetric and antisymmetric isotopomers (eg 686, 668).

Assimilation (MJ) [Prev] [Next]

Previously assimilated CH4, O3 and H2O using an isentropic (2D) model

• Currently extending assimilation model to 3D to allow temperature to be included

CFC Retrievals [Next] [Next]

Recent visit from Lars Hoffman and Reinhold Spang (FZ Juelich) who have been performing their own retrievals of CFC-11 and CFC-12 from MIPAS data (Proc SPIE, 2004)

• Used ESA-retrieved pT plus a band-model (BANDPAK) as a fast forward model (allowing the entire MIPAS dataset to be processed) for the CFC retrieval
• Consequence of using a band model is that the continuum term has to be fitted in a separate microwindow
• Will use MWMAKE and MORSE to validate results

IMK/IAA Data Users' Meeting [Next]

Email from Thomas Clarmann

The 1st meeting of the users of IMK/IAA-generated MIPAS data will be held at Forschungszentrum Karlsruhe (Leopoldshafen) from 8-10 December 2004. The current planning is to start on 8 December around noon and to finish on 10 December around noon. This is hoped to save most of you additional travel days.

Email Thomas for further information (Thomas.Clarmann at imk.fzk.de)

ASSFTS-12 Meeting [Prev] [Next]

(Atmospheric Science from Space using Fourier Transform Spectrometry)

Meeting to be held May 18-20 2005 in Quebec.

Email from Peter Bernath

While the focus of the meeting is on satellite FTS's (past, present and future), the scope of the meeting encompasses balloon and airborne FTS measurements, particularly for calibration and validation purposes.

Email bernath at uwaterloo.ca if planning to attend (either "Yes" or "Maybe").

The consolidated MIPAS L1b data that we have received from ESA are now visible. The period of time covered is September 2002 to December 2003 but it seems to me that there are many gaps. I have contacted John Remedios in Leicester to ask him if he expected more data from ESA. If you can also comment on this, I would be very grateful.

Unfortunately, we had to store the data on a machine which is not accessible by ftp. We hope to be able to sort this problem out soon. For the moment, the data are viewable and downloadable from the web at the following address:

http://badc.nerc.ac.uk/cgi-bin/data_browser/data_browser/badc/envisat-mip1b/consolidated

You will be prompted to enter your BADC user ID and password. The "envisat-mip1b" directory has currently two subdirectories:
- "data" contains the near-real time L1b data.
- "consolidated" contains the processed L1b data that we received on tapes.
We will come up with more consistent directory names in the future but we preferred to leave them are they are for the time being, because a number of scripts use the current names.

I hope this will be at least a bit helpful and that we can improve the archive and fill the gaps (?) soon. Please do not hesitate to contact us again if you meet problems in downloading the data.