Oxford MIPAS meeting#13
27 Aug 02

Present

Oxford: Anu Dudhia, Vivienne Payne, Chiara Piccolo
RAL: Victoria Jay, Jolyon Reburn

Instrument Status [Prev] [Next]

Email from H.Nett (see below)

MIPAS cooler problem on 6 Aug caused instrument to go into standby mode.
Nominal mode resumed 22 Aug

Software Updates [Prev] [Next]

New software in /home/crun/eodg/mipas

/L2/util/ Level 2 utilities
- cdproc.pro - see below under L2 Data
/Lv2PP/lv2pp.pro Lv2 Pre-Processor - L1C output file format minor change to v1.2
- Radiance data now written free-format instead of 8F10.4 since radiances >10000 encountered with orbit 2081.

L2 Data [Prev] [Next]

Automated IDL procedure cdproc to process L2 CDs now in place (for Unix or Linux machines), from any directory:

Slot a CD into drive
IDL> /home/crun/eodg/mipas/L2/util/cdproc

Program should then generate a series of residuals (.res) files, 1 per species, a file yyyymmdd.dat containing profile location data, a file yyyymmddmap.jpg containing an image (see http://www.atm.ox.ac.uk/group/mipas/L2/ for examples of images).

OPTIMO Retrievals [Prev] [Next]

(VP) Investigating anomalously high (>10ppmv) H2O over S.Pole in 504 retrieval - using ESA pT profile with OPTIMO H2O still shows high levels.

Email received from Norbert Glatthor (IMK) noting anomalous O3 retrievals above equator.

Occupation Matrix Statistics [Prev] [Next]

(CP) Investigating occupation matrix frequency in ESA L2 data [Results]

OMs identified as part of residual extraction (l2pres.pro)
Nominal OMs (001-006) used 95% of the time
618 next most common for constituent retrievals. This is a nominal OM but with all measurements/retrievals below 21 km removed (originally intended as a cloud-contamination OM). Seem to be used when pT retrievals below 18km are unavailable.
Several unidentified OMs also detected for H2O and O3 - these seem to be nominal OMs with a single MW switched off at a single altitude. Provisionally allocated labels 700-704

CO Retrieval [Prev] [Next]

As a vacation project, Ben Fletcher has been investigating feasibility of CO retrievals from MIPAS data (following on from Oliver O'Brien's M.Phys project)

Selected microwindows for a joint CO/Vibrational temperature retrieval
(AD) MORSE adapted for a joint retrieval of CO & VT.
Applied results to AMIL2DA Blind Test spectra (high latitude day-time conditions so expect non-LTE contribution) [Plot] - solid line shows `true' CO profile, dotted line shows a priori, symbols are retrieved CO with random error bars
- Top left - Retrieve CO only, ignoring non-LTE effects
- Top right - Retrieve CO only, use AMIL2DA mid-lat daytime VT in forward model
- Middle left - Retrieve CO only, use AMIL2DA polar-summer VT in forward model
- Middle right - Retrieve CO & VT, ignoring other species
- Bottom left - Retrieve CO & VT, modelling other species (H2O and O3 mainly).
Also applied results to profiles #5 and #60 in orbit 504 (day/night conditions at 45degN) [Plot]
- Similar profiles retrieved (as might be expected since similar latitudes) although non-LTE conditions presumably very different.
Conclusion is that, surprisingly perhaps, there does seem to be sufficient information in the spectra to usefully retrieve both CO and a vibrational temperature profile.

email from Herb Nett 21 Aug 02:

MIPAS recovering from cooler anomaly

This note is on an anomaly encountered with the MIPAS Stirling coolers of which a couple of you may not have been informed yet.

The event occured on 6 Aug, 3:18 UTC, when the accelerometers measuring the cooler vibration levels indicated values higher than 10 mg for more than 5 minutes. Such an event causes MIPAS to autonomously switch into its save 'Standby/Refuse' mode, ie, coolers, slide mechanism, other equipment powered off.

Following an analysis of the event, involving also experts from Astrium and Rutherford Appleton Lab., and two functional tests on 16/17 August, a decision had been taken to start a full cool-down cycle on Sunday 4:50 UTC.

After a nominal cool-down period the operational temperature of 70 K of the focal plane subsystem was reached on Monday evening, 19 Aug.

A check of recorded house-keeping information confirmed that compressors, displacers and vibration cancellation system (VCS) were performing nominally.

Final vibration levels of compressors and displacers were 2.5 mg and 2.9 mg, fully in line with values achieved after the initial cool-down during SODAP.

The instrument is at this moment in Heater mode (equipment powered) and all on-board tables are being re-loaded, following a 'cold reset' of the instrument.

MIPAS will be commanded into Measurement mode early tomorrow morning (Thursday) and we expect it to re-start sending high quality interferograms from the first Kiruna visibility orbit onwards.

Oxford MIPAS meeting#13 27 Aug 02

Oxford MIPAS meeting#13
27 Aug 02