Oxford MIPAS meeting#46
13 Jan 04

Present

Oxford: Alastair Burgess, Anu Dudhia, Vivienne Payne, Chiara Piccolo, Analia Quijano
RAL: Victoria Jay, Martin Juckes, Jolyon Reburn

Instrument Status [Prev] [Next] (Some details on the Envisat Web-Site and times taken from Instrument Availability web-site)

Unavailable 2003-12-09 16:08:33-19:30:00 Slide velocity anomaly
Unavailable 2003-12-18 06:04:46-11:35:00 ?
Unavailable 2003-12-18 14:44:28-18:09:00 ?
Unavailable 2003-12-25 02:20:48-11:13:00 Slide velocity anomaly
Unavailable 2004-01-06 13:36:00-18:09:00 Slide velocity anomaly
Unavailable 2004-01-09 14:27:28-18:18:00 ?
Unavailable 2004-01-11 06:51:40-12:20:00 ?
See email from Rob Koopman

From 10th Dec 03 a new algorithm was used which should remove the daily pitch jump (and the 3-4 day oscillation evident in MIPAS daily-mean pointing).

L1 Data (AB) [Prev] [Next]

Looking for L1B data from the off-line processor, but not with any success. It doesn't appear to be stored at BADC. Is there an ftp site?

L2 NRT Data [Prev] [Next]

In /home/crun/mipas/L2/NL/ [Plots of profile locations]

NRT Data received up until 12th January, plotted up until 31st December.
Software version 4.59 in use since 23 Jul 2003.
Problems in December (especially 18th-22nd) with AB and C bands caused loss of 30% of O3 and NO2 data for the month, while equivalent H2O retrievals switched to using B-band microwindows. See emails from Michael Hoepfner
Also recent problems with A band (no pT, therefore no other retrievals either)
Possibly also problems with incorrect auxiliary files being used in processing.

L2 OFL Data [Next]

In /home/crun/mipas/L2/2PODPA/

L2 OFL (off-line) data now received from 21 Oct - 20 Dec
One file per orbit, ie less fragmented than the NRT data.
Work in progress on modifying NRT diagnostics to cope with OFL data.(AQ)

Software Updates [Prev] [Next]

Software in /home/crun/eodg/mipas

/ILS/ Construct Apodised Instrument Line Shape. (CP)
Modified to apply linear spectral shift correction (based on coefficients derived from REC analysis of orbit 2081). Correction can be applied to AILS constructed either from the L1B parameters or from the `ideal' AILS.
/Lv2PP/ Lv2 Pre Processor (CP) [Next]
Set Cloud Index=0 for missing sweeps and, if A band is missing, derive from D band instead (using U.Le definitions of Cloud Index)
/rfm/ Reference Forward Model (AD)
v4.24 now released - a couple of bug fixes and 2 extra SO2 isotopes.

Auxiliary Data Updates (AD) [Prev] [Next]

New data in /home/crun/eodg/mipas

/OM/ Occupation Matrices
- /occ_6x/ OMs for MIPAS Off-line processing

Basic Envisat Atmospheric Toolbox (BEAT) (AB) [Next]

A set of routines for reading MIPAS, SCIAMACHY, GOMOS, GOME and TOMS data, eg using IDL interface and returning data as structures

See http://www.science-and-technology.nl/beat/

Now installed locally, requires extra line in IDL start-up command.
AB currently trying it out to read L1B data, but eventually we hope to convert all our L1/L2 access software to use these modules.

L1 Phase Error [Prev]

emails from Michael Hoepfner (IMK)

(7 Jan) I spotted again phase error problems (very likely) with mipas level-1 online spectra mainly on 2-Jan-2004, but also single ones on 1-Jan and 3-Jan (all in southern hemisphere). (See red/orange symbols in appended .pdf plots.)
(8 Jan) Plot of one limb-scan of orbit 9451 on December 21, 2003. Your suggestion was correct: missing of many data from 18-22 December is due to a phase problem of channel AB and C. Here, all tangent altitudes of channels AB and C seem to be affected, while the phase problem in November and January is related to distinct tangent altitudes, but to all channels. (see plot).

Minor Species (AB) [Prev] [Next]

GRL Paper on SF6 retrievals has been corrected and resubmitted [Next]
Currently looking at retrieval of NH3

Data Assimilation (MJ) [Prev] [Next]

Isentropic (2D) data assimilation code

CPU cost of data assimilation now proportional to the number of mesh points, but still increases non-linearly with time.
Will present results at EGS showing MIPAS O3, H2O and CH4 compared with other satellite instruments
Also looking at high H2O/low O3 features in upper stratosphere in polar autumn (eg Sep02)

RAL Retrievals (VJ) [Prev] [Next]

1D Joint retrievals of O3+H2O for orbit 2798 (12 Sep 02) now completed.

Observe some oscillatory features (as in the ESA NRT data) probably resulting from radiometric gain calibration differences in forward/reverse sweeps

Special Modes (VJ) [Prev] [Next]

S6 Special Mode (0.1cm-1 Resolution) data taken in July 2003

So far just a comparison of radiances with forward model calculations - radiances look reasonable

Isotopic Retrievals [Prev] [Next]

H2O & CH4 (VP)

Will look at MIPAS measurements and present results at the Quadrennial Ozone Symposium (Kos, 1-8 June 2004)

O3 (CP)

Literature suggests conflicting results as to whether there is any seasonal variation in concentrations of 686 and 668 isotopes
Spectroscopic data is being improved
Results from MIPAS will also be presented at QOS.

December Statistics [Prev] [Next]

Results for inclusion in MIPAS monthly report now collected.

Email from Rob Koopman (ESA) 9 Jan 04

In view of recent recurrences of erroneous behaviour of the MIPAS interferometer drive system (25 December and 6 January), the interferometer heaters will be switched on today (9 January 2004) for the duration of the winter. This will be the first use of these heaters during the nominal mission, and it is expected that their use will avoid the anomalies encountered last winter and during pre-flight testing at low interferometer temperatures. Note that this change only applies to the heaters of the interferometer unit; all other thermal subsystems (in particular the Sterling coolers) are operated without modification. Nevertheless moderate deviations of overall self emission are to be expected. An analysis will be performed over the next weeks to assess any product quality changes.

Oxford MIPAS meeting#46 13 Jan 04

Oxford MIPAS meeting#46
13 Jan 04