Oxford MIPAS meeting#9
02 Jul 02

Present

Oxford: Anu Dudhia, Don Grainger, Vivienne Payne, Chiara Piccolo
RAL: Victoria Jay
Leicester: John Remedios

Instrument Status [Prev] [Next]

See message at bottom of page

Software Updates [Prev] [Next]

New software in /home/crun/eodg/mipas

/L2/util - various routines from Reinhold Spang and Jolyon Reburn for reading MIPAS L2 data
/rec - REC analysis source code
/rec/util/l2res.pro - extract residuals from L2 data
/rec/util/avgres.pro - average residuals files
/L1B/util/l1bmap.pro - plot L1B scan locations on geographical map

Additional Species (VP) [Prev] [Next]

Using OPTIMO and BT1 spectra

CFC-11 and CFC-12 look OK, ClONO2 underestimates peak slightly, N2O5 may just be retrieving noise (may require wider microwindows to distinguish N2O5 features from continuum).
Results included in the AMIL2DA report.
Note that N2O5 `true' profile peaks at 30km, whereas MIPAS climatology for this latitude/season peaks at 40km - explanation?

Instrument Line Shape calibration (CP) [Prev] [Next]

Now using BOMEM-recommended procedure to interpolate reconstructed AILS between fitted reference points.

Note - no apparent trend in AILS shape with wavelength.
Still unresolved issues on whether to interpolate between bands (assume yes) and how to extrapolate at ends of A and D bands (currently using two extreme calibration points @933 and 2369cm-1 for any extrapolation).
Comparing with the ML2PP (which should be the shape that is used in the operational retrieval), Oxford AILS for MW O3__0013 (1039cm-1) - black curve - does indeed lie between the curves for the two local calibration frequencies (949cm-1,1073cm-1 - green,blue curves) whereas the ML2PP AILS - red curve - lies outside.
For MW O3__0001 (1122cm-1) the Oxford AILS is almost identical to the local reference curve (1129cm-1), while the ML2PP is outside both reference curves.
It looks like there is a problem with the ML2PP interpolation rather than the Oxford interpolation. Sven Bartha (Astrium) has suggested several reasons why this might occur and Alastair Burgess (ESTEC) has been asked to reproduce the results.

REC Analysis (AD) [Next]

Viewgraphs to be presented at 38th SAG meeting (July 4th)

Applied REC analysis to all residuals from orbit 504 (62 profiles x 17 sweeps x all microwindows)
Retrieved species have low residual signatures (as hoped)
Non-LTE and CO2 line mixing signatures not as large as expected (~1)
Possibly underestimating some minor species (ClONO2, COF2, CFC-12...)
1st derivative spectra show spectral shift -0.001 to +0.001cm-1 across bands A-D, also shift of approximation +0.001cm-1 from 68-6km.
Clearly a problem with microwindow CH4_0021 (Backup CH4 microwindow in the C band)

Profile Levels

Discussion on whether there is/should be a standard set of pressure/theta/sigma levels for comparing MIPAS results to other data sources. Check at SAG meeting if anything has been agreed.

email from Herb Nett to CalVal group, 02 Jul 02
... we are indeed somewhat behind the original (pre-launch) schedule with regard to specific calibration measurements IF1 ... IF16.

This was mainly due to a few 'payload switch-off' events (PLSOL) during May & June and due to some data recovery and dissemination problems in the past. See also earlier e-mail to mict on 11 June.

Good news are

MIPAS has been continously in measurement mode since last PLSOL recovery on 15 June
Mission planning activities are progressing well and we hope to complete most of the IF measurements by around mid next week (10 July). In particular it seems that the -critical- non-linearity measurement (IF4) has finally been successful (!!) after several attempts. Acquisition took place in orbits 1609-1668, 21 - 25 June
The most recent of several patches in the MIPAS ground processor s/w was successfully installed in Kiruna on 28 June. Since 29 June we have routine processing of MIPAS L1B (+ partly L2) data in the PDS.

The slightly less good news is that today I cannot confirm a date for the start of data distribution to the CalVal teams.

In summary, we plan stable operation of MIPAS in its nominal measurement scenario from approx. 11 July onwards and for the duration of the first correlative campaigns.

Oxford MIPAS meeting#9 02 Jul 02

Oxford MIPAS meeting#9
02 Jul 02