Oxford MIPAS meeting#55
25 May 04

Present

Oxford: Alastair Burgess, Anu Dudhia, Don Grainger, Vivienne Payne, Chiara Piccolo, Analia Quijano
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.
Awaiting decision of Anomaly Review Board before reactivating [see email from Rob Koopman]

L2 OFL Data (AQ) [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]

Updates on anomalies identified at QWG#3

Offset of exactly 1 second between NRT and OFL L2 profiles
- Thought to have been fixed with v4.61, although it turns out only to have been fixed in the most recently processed v4.61 NRT data, earlier v4.61 still shows the discrepancy [Next]
- AB has now sent a report and an example to ESA

EGU, Nice 25-30 Apr 2004 (VJ) [Prev]

Envisat session include a large number of presentations from the IMK and IAA groups on MIPAS results, particularly on PSCs, non-LTE and denitrification

Also a number of MIPAS validation results, presumably all included in the ACVE-2 meeting.

Reduced Resolution (AD) [Next]

It has been recommended that MIPAS be operated at around 41% max OPD in future to minimise mechanical problems

Ongoing discussions as to whether this will mean L1B spectra on 0.06, 0.061 or 0.0625cm^-1 wavenumber grid.
Initial microwindow selection (for 0.06cm^-1 grid) suggests similar retrieval characteristics to off-line processing can be achieved with similar bandwidth: [TEM] [PRE] [CH4] [H2O] [HNO3] [N2O] [NO2] [O3] (Plots list information content in bits, and total bandwidth of all microwindows used, solid lines are total error and dotted lines are random error).
Bandwidth (proxy for CPU time) for 0.06cm^-1 always larger than for 0.025cm^-1 for similar information content, but this is only an initial microwindow selection without any consideration of CPU cost.

Isotopic Retrievals (VP,CP) [Prev] [Next]

MORSE now modified to retrieve isotopomeric ratios using look-up tables

(VP) Retrieving ratios for H2O and CH4. Examples (orbit 2081) [HDO], [delta HDO/H2O] - shows expected depletion, particularly in the lower stratosphere
(CP) Retrieving ratios for O3. Examples: [single profiles] (black is climatology) - Isotopes#2 (668) and #3 (686) show slight (~5%) enhancement, #4 (667) and #5 (676) too noisy for meaningful answer from a single profile.
Results to be presented at QOS, Kos, 01-08 Jun 2004.

Email from Rob Koopman (ESRIN) to MIPAS QWG, 13 May 2004

The regular MIPAS instrument operations are suspended since 26 March, following an increasing number of anomalies related to the behaviour of the instrument interferometer slides. A test plan, aiming at the identification of the possible causes of the anomalies, was executed during April. While the cause of the anomalies is not yet known in detail, the investigation team has reached the conclusion that the anomalies are located in the non-redundant part of the instrument. This preliminary conclusion implies that the MIPAS instrument cannot be anymore operated in its nominal mode.
Workaround solutions are now elaborated by the anomaly investigation team set-up by ESA together with the MIPAS instrument prime contractor, ASTRIUM GmbH. These solutions should allow operating the instrument in an alternative mode, without risks for the instrument itself or for the satellite. Alternative operations modes have been proposed and are currently under analysis. Once the alternative operation mode is selected and approved, a commissioning activity will be performed with the objective to calibrate and validate the resulting MIPAS Level 1 and Level 2 products. The commissioning activity will involve the MIPAS instrument teams, the product quality teams and the data validation scientists.
The above activities will last several months. Consequently the regular delivery of MIPAS products is not envisaged before next Autumn at the earliest.
Next MIPAS anomaly report will be provided around mid-June.

Oxford MIPAS meeting#55 25 May 04

Oxford MIPAS meeting#55
25 May 04