Oxford MIPAS meeting#51
23 Mar 04

Present

Oxford: Alastair Burges, Anu Dudhia, Tom Ibbotson, 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 from 13th-15th Mar (reason unknown).
Plan 3 orbits of operation (10812-10815) on 25th March running interferometer at 95% resolution (ie 95% normal mirror movement). Initially to test out software in this mode, eventually to run for a longer period to investigate ongoing interferometer problems.

L2 NRT Data (AQ) [Prev] [Next]

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

NRT Data received up until 19th Mar, plotted up until 16th March.
Software version 4.61 in use since 17 Mar 2004 (although some Kiruna data for 10 Mar was also processed with v4.61) - see email from Rob Koopman.
Daily zonal mean traces at 39km showing a gradual increase in low latitude CH4 and H2O - approximately 10% since beginning of March.

L2 OFL Data (AQ) [Prev] [Next]

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

Now started to receive L2 OFL (off-line) data covering Aug - Sep 2002, processed using v4.61
Some unidentified OMs being detected in 2002 data - not yet determined whether this is the same problem as experienced with the NRT data (due to the preprocessor modifying OMs) or a bug in our software identifying OMs.
Comparisons with L2 NRT data show a difference of exactly 1 second in profile times - explanation?

O3 Retrievals (CP) [Prev]

Comparing ozone sonde measurements with colocated MIPAS retrievals

So far identified 8 out of 38 matches where there is an unexplained discrepancy in the results

H2O & CH4 Isotopic Retrievals (VP) [Prev] [Next]

Using local retrieval code MORSE to retrieve isotopic concentrations

Verified that MORSE works correctly with simulated data
Single profile results with real data show expected decrease in HDO at the tropopause, but no clear signal in H2 18O
[Plots] of results for Orbit 2081, scan#13 - dashed line shows a priori, solid red line main isotope.
Obtained poster from Jo Urban presented at the COST meeting showing H2O isotope results from ODIN/SMR.

COST 723 Workshop (Noordwijk, 11-13 March) (VJ)

Data Exploitation and Modeling for the Upper Troposphere and Lower Stratosphere

Most presentations involving data assimilation used MIPAS data.
Many presentations are on the web-page: http://www.cost723.org/meetings/ws1/contributions.htm

BEAT Software (TI) [Prev] [Next]

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

Tom Ibbotson (vacation student) has been attempting to modify our IDL L2 reading software to use BEAT-I modules

Main problem is that standard BEAT_FETCH functions only return single profiles/scans at a time, whereas we've been using IDL functions which load the entire file
Sidney Cadot (S&L) has been providing assistance and has (informally) supplied a more general L2 function which loads the entire file, but there appear to be several bugs.

Error Analyses [Prev]

MIPAS error analyses generated by the microwindow selection program

Results for L2 Off-Line products have now been added: http://www.atm.ox.ac.uk/group/mipas/err/

OMs for Minor Species [Prev] [Next]

Occupation matrices and error analyses have been generated for the minor species, included in anonymous ftp site

ftp.atm.ox.ac.uk
directory: /pub/user/dudhia/microwindows

I have selected 3 OMs for each species, eg OM_C2H6000.DAT, OM_C2H6001.DAT and OM_C2H6002.DAT. The 000 are most conservative, ie should be well-behaved and the 002 are the most speculative.

Seletion criteria:

000: maximum error 50%, minimum information per MW 0.5 bits
001: maximum error 75%, minimum information per MW 0.25 bits
002: maximum error 90%, minimum information per MW 0.1 bits

(these maximum error estimates assume an a priori uncertainty of 100%). Here is a summary of the altitude range and number microwindows for each species and OM. Where no atmosphere is specified, assume mid-latitude day-time conditions.

	'000'	'001'	'002'
C2H6	6-18km (4)	6-21km (7)	6-21km (8)
CCL4	9km (2)	9-15km (3)	6-15km (7)
CLO	18-21km (3)	15-21km (5)	15-21km (9)	'polar winter' atmosphere
CLONO2	15-39km (4)	12-42km (6)	9-42km (7)	'nighttime' atmosphere
CO	6-52km (6)	6-68km (6)	6-68km (6)	'nighttime' atmosphere
COF2	15-36km (4)	15-42km (7)	15-42km (10)
F11	6-24km (4)	6-27km (5)	6-27km (6)
F12	6-36km (4)	6-36km (5)	6-39km (6)
F14	9-52km (4)	9-60km (6)	9-60km (7)
F22	6-27km (5)	6-33km (6)	6-33km (7)
H2O2	6-30km (5)	6-33km (7)	6-33km (10)
HCN	9-33km (5)	9-42km (8)	9-42km (9)
HOCL	18-30km (5)	18-30km (6)	18-33km (6)	'polar winter' atmosphere
N2O5	15-36km (4)	15-39km (5)	15-39km (5)	'nighttime' atmosphere
NH3	6-21km (3)	6-21km (7)	6-24km (8)
OCS	6-24km (6)	6-24km (10)	6-24km (10)
SF6	6-24km (3)	6-30km (4)	6-30km (5)
SO2	12-21km (5)	12-21km (6)	12-21km (9)

For SO2 and NH3 the results are probably too optimistic, since Alastair's work suggests that the actual atmospheric concentrations seem to be much lower than those assumed in the mid-latitude day-time profile.

Email from Rob Koopman (ESRIN) Fri, 19 Mar 2004
Subject: Activation of MIPAS IPF 4.61 in operational processing chains

The MIPAS data processor 4.61 has been installed at all processing centres.

Improvements: The algorithms for this processor have not changed, but a number of coding errors (in particular incorrect cloud detection, corruption of level 1 spectra, inconsistencies between pT and trace gas retrievals) have been resolved. Minor discrepancies remain in level1B ILS retrieval and cloud detection in sliced products, and will be addressed in the next release. They do not affect generation of level 2 products in Off-Line mode. Also a minor processor configuration change has been performed, and the ADFs are available as usual on the envisat web site.

Activation:

In the Near-Real-Time Level 1B and Level 2 production, this update is active with immediate effect on products from 17 March onwards.
In the off-line consolidated level 1B production at the LRAC, this update has become effective as of today, whilst processing products from the end of February.
Although the IPF 4.61 is also operational since 15 March at the DPAC, Level-1-to-2 processing has been suspended there and will resume upon the arrival of IPF4.61 level 1B products from the LRAC.

The DPAC resources thus liberated have been temporarily added to the reprocessing chain. On 17 March, the DPAC has begun to process the MIPAS validation data set from level 0 to 2, with reconstructed calibration history, in off-line configuration. Information on the atmospheric validation data sets will be provided in a separate message.

Oxford MIPAS meeting#51 23 Mar 04

Oxford MIPAS meeting#51
23 Mar 04