Oxford MIPAS meeting#89
24 Jan 06

Present

• Oxford: Anu Dudhia, Jane Hurley, Joanne Walker, Claire Waymark.
• RAL: Alison Waterfall.

Instrument Status [Prev] [Next]

Functioning normally as far as we know, currently switched on for 4-5 orbits per day.

• Some details on the Envisat Web-Site including Instrument Availability web-site
• Latest version of Mission Planning Document covering 1 Jan 06 to 05 Mar 06: [.xls] [.html].
  • 30JAN06-10FEB06 measurements in UTLS-1 mode in support of the CR-AVE campaign; 4 orbits per day, both in ascending and descending track over San Jose, Costa Rica (9�� 59' North, 84�� 04' West).
  • 11FEB06-05MAR06 MIPAS measurements in UTLS-1 mode in support to the ESABC campaign; 4 orbits per day, both in ascending and descending track over Kiruna.

L1 Data [Prev] [Next]

New L1B processor test data distributed from ESRIN (23JAN06) for the following orbits/dates [Coverage]

• 10600 10MAR04 0.025 Res 17 sweeps (reprocessed)
• 12788 10AUG04 0.0625 Res 17 sweeps (new data)
• 12963 22AUG04 0.0625 Res 17 sweeps (reprocessed)
• 14404 01DEC04 0.0625 Res 27 sweeps (reprocessed)
• 17540 08JUL05 0.0625 Res 27 sweeps (new data)

HiRDLS Comparisons (CW) [Prev] [Next]

Continuing to attempt to use MIPAS retrievals as input to RFM to simulate radiances in the 11/21 HIRDLS channels which are not fully overlapped by MIPAS bands.

Cloud Parameters (JH) [Prev] [Next]

Investigating change in information content of various cloud parameters that might be retrievable from MIPAS spectra at original 0.025 and new 0.0625 cm-1 resolutions.

Also preparing report on D-band cloud flag issues for next QWG.

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

Re-selecting MWs after Jacobian bug.

pT, H2O, CH4 and N2O completed so far (also N2O5).

NOx (JW) [Prev] [Next]

Plotted (NO2+2N2O5) (Night-Day) as estimate of day-time NO concentration.

Results look reasonable for the stratosphere, but still need to check for influence of a priori.

O3 validation with ECMWF (AW) [Prev]

Comparisons show good agreement at most latitudes: generally within 10%, discrepancy mostly due to a systematic difference in altitude of peak.

At high latitudes (65-90) agreement is noticeably worse. Assuming there is no reason/evidence for MIPAS to be worse at high latitudes, suspect this represents problems in the ECMWF O3 data.

L2 validation (AW/AD) [Prev] [Next]

More general validation issues

• It has been decreed that only MIPAS v4.61 should be used for validation, although this seems to be based on a single example where v4.61 and v4.62 data disagreed with v4.61 looking more plausible.
• According to Thorsten Fehr (ESA) there should be no difference between v4.61 and v4.62 processors, although presumably differences may arise from changes in input data, eg calibration.
• It is now known that L2 profile values are limited to 1E-10: 1E+10 [Prev] when the retrieval produces results outside this range, but there does not yet seem to be any clear policy for the validation papers whether these values should be included/excluded in the profile comparisons.
• Marco Ridolfi (Bologna) has sent the following regarding flagging data quality

  The current status of MIPAS Level 2 products flagging is the following:

  cloudy limb-views are filtered-out before the Level 2 analysis, therefore in the ESA Level 2 files you can find only cloud-free profile data points.

  It is in the ESA plans to include also the cloud-filtering flag in the output files but so far there is no cloud flag in the MIPAS Level 2 files.

  MIPAS Level 2 products come with two flags:

  1. quality_flag: set to -1 if the retreival failed set to 0 otherwise.
  2. conv_id:
     = 0 convergence reached
     = 1 too many macro-iterations
     = 2 too many micro-iterations
     = 3 allowed run-time exceeded
     = 4 failed (e.g. division by zero...)
     

  The validation activity should be limited to the profiles with quality_flag = 0 and conv_id = 0.

Atmospheric Science Conference 2006 [Prev]

http://earth.esa.int/atmos2006

To be held at ESRIN 18-12 May 2006

Poster abstracts on the following topics have been submitted from the Oxford group.

• Measurements of CF4 (CP)
• Enhanced HNO3 in the 2005 Arctic Stratosphere (CW)
• Retrieval of Cloud Top Height (JH)
• Trends in CFCs (AB)
• Measurements of NOx (JW)

AD Jan 06