Oxford MIPAS meeting#144
19 Aug 08

Present

Oxford: Anu Dudhia, Jane Hurley, Joanne Walker, Claire Waymark

Instrument Status [Prev]

Operating continuously since 1st Dec 2007 in standard cycle of 8 days NOM, 1 day MA, 1 day UA.

31 Jul 08: Special calibration tests (IF9, IF16) scheduled but lost due to MCMD anomaly
14/15 Aug 08: most recent MA/UA observations

Recent interruptions in data [MIPAS Availability]

31 Jul 08: unavailable from 03:49 to 1st Aug 09:10 due to a "MCMD transfer acknowledgment error. This latter is a known anomaly that was recovered at ESOC" (see 2.2.2 in the July report)

General Information

Mission Planning Document for 2008 [XLS] [HTML].
MIPAS Mission Plan v4.3 (March 08) [DOC] [PDF]
Currently defined measurement modes
Envisat Web-Site

July Monthly Report [Prev]

July monthly report available on ESA web-site

[Summary]

L1B Data [Prev]

[L1B Data Coverage]

"Near Real Time" (NRT) data available on Kiruna or ESRIN ftp sites ~ hours after acquisition.

No current problems

"Off-line" (OFL) L1B data available on D-PAC ftp site approximately 2 weeks after acquisition.

Continued problems acquiring ftp connection from Oxford (unlike NRT data sites)

Oxford L2 Processing (AD) [Prev]

[Oxford L2 Data Coverage]

Running MORSE to retrieve our own L2 data (ESA species plus CFC-11,CFC-12,N2O5,ClONO2 and CO)

Processing all new "off-line" data currently with a lag of around 3 weeks (2 weeks for L1B data to appear, 1 week to process L2 locally) - most recent day 26th July
Processing of all data since start of mission now complete - reprocessing days in June/July 2007 with modified N2O5 microwindows to ensure uniformity with the rest of the data (v1.02) - older version has obvious bias, eg [10mb - red points from 2007]
Processing NRT data - same L2 algorithm but restricted to pT, H2O and O3. Usually available a couple of days after acquisition - most recent day 17th August. Now also processing MA and UA mode NRT data.

Antarctic Winter (AD) [Prev]

From the Oxford L2 [trend plots] for 65S-90S at 10mb

[Temperature] Gradually rising throughout August so far to around 195K but stil cooler than in previous years a few K lower than normal through most of July, but rose to 193 K on July 23rd, more in line with previous years.
[HNO3] had been below normal but seemed to be returning to usual levels towards the end of July
[CFC-11] Still anomalously high throughout July - probably related to problems with the tabulated absorption coefficients at low temperatures.
[O3] rising throughout July, as in most previous years

CO retrievals (JW) [Prev]

Revisiting joint (non-LTE) retrieval of CO + VT

Now assessing required accuracy of vibrational temperature retrieval to allow good CO retrieval

Cloud Detection (JH) [Prev]

Investigating different methods of cloud detection (in addition to current operational "cloud index")

5 different methods identified for
Now examining robustness of each methods to the change in MIPAS spectral resolution

TES Limb Retrievals (CW) [Prev]

Run MORSE to retrieve pT,H2O,O3 and HNO3 from TES limb-spectra (27Jun05) TES limb spectra are acquired in sets of 3 ("scans #4,#5,#6") with different spectral filters.

Only Scan#4 has the filters necessary for a good pT retrieval, so using Scan#4 retrieval as a priori pT for scans #5,#6
Looking at the engineering altitudes of the retrieved 10mb surface [Plot, blue=MIPAS, yellow=CIRA climatology, red=TES] TES altitudes seem to be 4-6km below climatology (cf MIPAS about 1km above), with an unusual feature around 50S (possibly a retrieval artifact since this appears in the same place on both ascending and descending orbits when the Aura satellite itself is at different locations)
Now checking whether the cloud detection (using the MIPAS Cloud Index with TES spectra) also shows a similar difference in cloud top height.

MA Mode Microwindows (AD) [Prev]

Original microwindows used for Oxford processing of MA and UA mode data were selected only for polar winter conditions, so likely to suffer from non-LTE problems under other conditions (investigated by LMV).

A new set of microwindows has now been selected

Based on all 5 model atmospheres, so allow for non-LTE errors under all conditions
Assume nominal mode microwindows are still used (at least those which contribute significantly above 18km - bottom of MA mode scan pattern), - these are effectively "supplementary" microwindows for MA and UA mode observations - so should be more consistent with nominal mode retrievals where altitude ranges overlap
[List] - MW numbers 03xx are current nominal mode MWs, 041x are supplementary MA mode MWs.

These will be used from 1st Aug 08 onwards in the Oxford L2 processing, and all past MA/UA mode data will be reprocessed to use same microwindows.

ACPD Papers [Prev]

Papers selected from the ACPD website for discussion

"Detection of ship tracks in ATSR2 satellite imagery": E. Campmany et al (published 01 Aug 2008, open until 26 Sep 2008); Introduced by JW
"Cloud's center of gravity - a compact approach to analyze convective cloud development": I. Koren et al (published 23 Jul 2008, open until 17 Sep 2008); Comments being collected by JH.
"Comparison of CMAM simulations of carbon monoxide (CO), nitrous oxide (N2O), and methane (CH4) with observations from Odin/SMR, ACE-FTS, and Aura/MLS": J. J. Jin et al (published 09 Jul 2008, open until 03 Sep 2008); Comments being collected by AD.

Other MIPAS-related papers in the Open Discussion phase, which may be adopted at a future meeting

"Atmospheric tracers during the 2003-2004 stratospheric warming event and impact of ozone intrusions in the troposphere": Y. Liu et al (published 17 Jul 2008, open until 11 Sep 2008)

Summary of the July Report

(F.Niro, 4 Aug 08)

MIPAS is back to full-time mission (100% duty cycle) since 1^st December 2007.
Since 3 March 2008 the auto-recovery procedure implemented at ESOC was dismissed and replaced with a manual procedure. As a result the re-initialization gap is no longer present in the MIPAS data.
The MIPAS level 1 NRT processing was restarted on 1^st February 2008 at Kiruna and ESRIN stations, the products are available via ftp rolling archive.
During the reporting month MIPAS performs well; in fact only one instrument anomaly was observed due to IDU error, however MIPAS was unavailable from 30 Jun 22:05 to 1^st Jul 07:00 due to a planned Orbit Control Manoeuvre (OCM). Furthermore the instrument was unavailable from 31 July 03:49 to 1^st Aug 09:10 due to a MCMD transfer acknowledgment error. This latter is a known anomaly that was recovered at ESOC (see ?2.2.2).
Special Planning was commanded until 4 July 2008 in support to the Teresina Campaign. During 5 – 31 July the nominal MIPAS scenario was planned consisting in 8 days of NOM, one day of UA and one day of MA mode. During 31 July special in-flight calibration were planned (IF9, IF6 and IF11), but these measurements were lost due to the MCMD transfer acknowledgement error (see previous paragraph). A more detailed description of the instrument planning for the reporting month can be found in ?2.2.1.
MIPAS weekly statistics since 2005 show the improvement of the instrument performances and the increase of duty cycle in the last year. The availability of L1 NRT products is also presented in this paragraph (see ? 2.2.4).
The availability of L1 OFL products with respect to the expected time is stable around 95% in the last months (see ?2.2.5).
The instrument temperatures slightly decrease during the reporting month in line with the seasonal trend (see ? 2.3.1).
The cooler performs well during the reporting month; the vibrations were well below the warning level of 8 mg (see ? 2.3.3).
The long term trend of ADC max counts in channel A1 shows a strong correlation with the instrument self-emission and with the detector ice contamination. During the reporting month the ADC counts start to decrease following the variation of the instrument temperature (see ?2.3.4).
The monitoring of the spectral correction factor shows a slightly decreasing trend; nevertheless the variations over more than two years of operations are really small ( 2 ppm). The observed spreading of the points is due to the noise in the determination of this parameter (see ? 2.4.2).
The gain weekly increase during the reporting month is nominal, the maximum of gain increase in all the MIPAS bands remains well below the acceptance criterion of 1%/week (see ? 2.4.3.1).
The analysis of the accumulated gain allows monitoring the level of detector ice contamination. During the last year we observed a decreasing slope of the gain curve, showing that the detector is more and more “ice-free”. This is due to the better performances of the cooler obtained with more frequent decontamination (see ?2.4.3.2).
The absolute mispointing is stable around a value of -25mdeg. The seasonal variations of the pointing error are small and below the fixed threshold of 8mdeg. Less and less stars are available in the last months for the LOS calibration, as a result the mispointing estimation is less precise now with respect to the beginning of mission (see ?2.4.4).
The long term monitoring of fringe count errors (FCE) shows that the width of the statistical distribution of the FCE can be used as a measure of the INT performances. In particular we observed that the FCE can be correlated with the number of IDU errors. This correlation is evident during the bad periods of the MIPAS mission (June 2005 and February 2006), while during the last months no clear correlation can be found (see ? 2.4.5.1).
The long term monitoring of the detected spikes shows that the number of detected spikes in channels A1, A2, B1 and B2 is varying with time with some peaks probably related to variation of the solar activity. The channels C and D (the detector most affected by spikes) didn’t show any trend so far. From this analysis we can conclude that the number of detected spikes is too small to impact the L1b products quality (see ? 2.4.5.2).
The level 0 NRT daily reports can be accessed at the following address:

Oxford MIPAS meeting#144 19 Aug 08

Summary of the July Report

Oxford MIPAS meeting#144
19 Aug 08