Oxford MIPAS meeting#96
16 May 06

Present

• Oxford: Anu Dudhia, Alastair Burgess, Jane Hurley, Joanne Walker, Claire Waymark, Chiara Piccolo.

Instrument Status [Prev][Next]

April monthly report is here [Summary below] [Prev] [Next]

• Mission details are often available on the Envisat Web-Site including Instrument Availability.
• Latest version of Mission Planning Document covering 1 Jan 06 to 25 June 06: [.xls] [.html].
• Mission Planning Document with overpass list (Apr06-May06): [.xls] [.html].

L1 Data [Prev][Next]

There have been a couple of emaild from DPAC explaining that some RR L1B data has been incorrectly processed and has been removed from their servers.

L1B RR coverage maps may be found here.

HiRDLS Comparisons (CW, AB, CP, AD) [Prev][Next]

(AB) Generalised code to perform integrations of the MIPAS spectral regions corresponding to HIRDLS filter functions. Now investigating 'operational' species retrievals from RR MIPAS data for subsequent cross-validation with HIRDLS.

(CW) Looking a MIPAS/ HIRDLS height comaprisons and validation [Stratosphere only].

TES/MIPAS/ODIN/ACE Comparisons (CP) [Prev]

T Comparison against ACE has shown some problems (M. Ridolfi). Still have problems finding correct error covariances to make proper comparisons. [Next]

Progress in ODIN comparisons.

CF4 retrievals (CP) [Next]

Poster from the Atmospheric Chemistry meeting is here.

Poster shows correlations with N2O and with SF6, for calculating lifetimes.

Used smoothing constraints and obtained almost constant VMRs with height and latitude.

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

N2O5 re-selection completed. Anu is writing a short summary explaining which MWs one should use in the nominal case as there are a number that overlap due to different selection criteria.

Cloud Parameter Retrievals (JH) [Prev][Next]

Still investigating the reading of SEVIRI data.

Looking for a routine cloud top height product, probably from Envisat.

Poster from the Atmospheric Chemistry meeting is here.

NOx (JW) [Prev] [Next]

Poster from the Atmospheric Chemistry meeting is here.

Looking at using the new N2O5 MWs.

CFC (F11,F12) Retrievals & Trends (AB) [Prev] [Next]

Paper from the Atmospheric Chemistry meeting is here.

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

(AD) Found OM assignment bug in webpage creation. Hope to update pages in a few days.

Summary of the April monthly report (F.Niro, ESRIN)

• The MIPAS instrument performance during April 2006 improved considerably with respect to the previous month, indeed, apart from the ten anomalies due to the platform switch-off during 6 - 10 April and the MPS problem of 28 April, only seven IDU velocity errors were recorded for the reporting month.
• As already mentioned an ENVISAT PLSOL occurred the 6th April; as a result all the payload instrument were switched off and a critical recovery procedure was undertaken to put all the instruments back to operation. In particular for MIPAS the recovery procedure ended on the 10th April, and as a consequence, ten measurement segments were lost.
• The effect of the PLSOL on MIPAS performance was a passive decontamination of the instrument, in fact since the cooler was also switched off we had a warming up of the detector which yields to a removal of some ice. The effect of this ice decontamination was a reduction of the gain increase and of the noise level; furthermore we observed also a reduction of cooler compressor vibration and a general decrease of the IDU anomaly rate.
• The instrument was operating the entire month on UTLS-1 mode, in particular the following campaigns were carried out:   o During first two weeks of April 2006 in support of the SAUNA campaign; 4 orbits per day, both in ascending and  descending track over Sodankyla, Finland (67.37 °N, 26.63 °E).   o During last two weeks of April 2006 in support of the INTEX-B campaign; 4 orbits per day, both in ascending and descending track over Hawaii (19-28 April) and Anchorage-Alaska (5-14 May)
• The monitoring of the instrument temperatures is reported in this MR, the most important temperature fields remain stable, the deviations being always below 1K, nevertheless the CBB temperature was 6K higher at the moment of restart MIPAS after the PLSOL, this anomaly was quickly resolved in the following measurement segment (see § 2.3.1).
• The cooler performance was also closely monitored during this month. The cooler seems to perform really well, the vibration being well below the warning level of 8 mg, in particular as already cited the compressor vibrations were reduced by 1mg after the PLSOL (see § 2.3.3.1).
• The gain, spectral and line of sight calibrations were carried out nominally during the reporting period, including the dissemination of the related ADF (see § 2.4.2, § 2.4.3, § 2.4.4).
• A monitoring of the absolute gain increase since the last decontamination (June 2005) is presented in this MR besides the long term weekly increase. This monitoring will be updated from now on and will help the planning of the future decontamination activity, expected for mid May 2006; as already reported the PLSOL causes a sharp decrease of the gain accumulation rate which went down from 30% to about 7%. This decontamination, occurred by chance, probably will be enough to keep the gain increase acceptable for the next months; therefore the decontamination to be planned for the end of May is maybe not needed, unless the cooler performances have to be stabilized (see § 2.4.3).
• The level 1 quality monitoring of the OFL products created at D-PAC is on going for a sub set of data. The quality check of the considered L1 products has demonstrated an overall good quality of the D-PAC results. Nevertheless a major problem was observed few days ago on L1 data from 3 - 23 June 2005 and 29 July - 11 Aug 2005. These data have very poor radiometric calibration due probably to wrong gain calibration ADF generated just after the decontamination of June 2005. This problem is now under investigation and a message will be sent out to alert the scientific user community, thereafter these data will be deleted from D-PAC server and reprocessed with correct ADF (see § 2.4.6.1).
• A quality control of the entire set of L2 products processed at D-PAC with IPF 4.65 was completed, revealing an overall good quality of the products, nevertheless an anomaly was found for some orbits of 21 - 22 Aug 2004. After the investigation we found that the problem was due to a corruption in the band D spectrum. Indeed the processor flags all the sweep as corrupted even though only one single band is corrupted. This processor specification which seems really restrictive, in particular for the band D which is not used in the retrieval, should be probably revised in the next QWG (see § 2.5.3.1).