Oxford MIPAS meeting#116
17 Apr 07

Present

Oxford: Anu Dudhia, Jane Hurley, Luis Millan-Valle, Claire Waymark

MIPAS currently in the middle of a 10day nominal operating sequence (1 day MA, 3 days NOM, 2 days off, 2 days NOM, 2 days off)

Mission Planning Document for 2007 [XLS] [HTML].
Currently defined measurement modes
Envisat Web-Site

March Monthly Report (JH) [Prev] [Next]

Full report obtainable from http://earth.esa.int/pcs/envisat/mipas/reports/monthly/

Summary below.

Precision Validation [Prev]

Paper now published in ACP http://www.atmos-chem-phys.net/7/1915/2007/acp-7-1915-2007.html

Cloud Parameters (JH) [Prev] [Next]

Scheme to retrieve Cloud Top Height, Cloud Top Temperature and Cloud optical thickness.

Running through a year's worth of (full resolution) data, retrieving 1 day in 10. Results for poster/paper at Envisat Symposium.
SVD analysis of simulated data: first extract the singular vectors that model the clear atmospheres, then see if further (orthogonal) vectors can be derived to model cloudy spectra.

Mesospheric Retrievals (LMV) [Prev] [Next]

Trying a linear least-squares fit retrieval for pT, O3 and H2O using entire MIPAS bands (screening out lines affected by non-LTE effects and gases other than CO2).

Works satisfactorily for 52/60/68km full resolution data for pT and O3, although H2O results differ significantly from ESA L2 product - results will be presented on poster/paper for Envisat Symposium
Problems attempting to apply analysis to reduced resolution data
- L1B data from Aug04 (RR17) has significant radiometric offset, which is not allowed for in current retrieval scheme
- Full MA mode data from Dec05 results in negative temperature retrievals - possibly also due to radiometric offsets.

MIPAS/TES Retrievals (CW) [Prev] [Next]

Aim is to combine MIPAS limb measurements of stratospheric O3 with TES nadir-viewing measurements to obtain more information on tropospheric O3 profile (basically how TES was supposed to work before their problems with limb-views)

Running joint p,T,O3,H2O,surface temperature nadir retrieval for TES for 28Jan05.
Results will be presented in poster/paper for Envisat Symposium.

Stratospheric Trends (AD) [Prev] [Next]

Running our local MIPAS processor MORSE on selected days throughout the MIPAS mission to try and estimate stratospheric trends.

The following days are being processed (BOLD font for days which are now completed)

Mode	Dates
FR17	09JUL02	23SEP02	23MAR03	22SEP03	21MAR04
RR17	17SEP04
RR27	28JAN05	21MAR05	16MAY05	10AUG05	12JAN06	13MAR06	25SEP06	14JUN06	04JAN07

Darwin Orbits (AD) [Next]

At the request of H.Sembhi from Leicester, also running MORSE for selected orbits coinciding with the field campaign based at Darwin during Nov/Dec 2005.

Orbits to be processed are:

Date	16NOV05	22NOV05	25NOV05	30NOV05	01DEC05	01DEC05	02DEC05	04DEC05	05DEC05
Orbit	19417	19503	19546	19610	19624	19632	19646	19667	19689

ACPD Papers [Prev] [Next]

Papers selected from the ACPD website for discussion

"Vertical profiles of lightning-produced NO2 enhancements in the upper troposphere observed by OSIRIS": C. Sioris et al. (published 11.04.2007, open until 06.06.2007); Introduced by AD.
"Global statistics of liquid water content and effective number density of water clouds over ocean derived from combined CALIPSO and MODIS measurements": Y. Hu et al. (published 28.03.2007, open until 23.05.2007); Comments being collected by JH.
"Retrieval of temperature profiles from CHAMP for climate monitoring: intercomparison with Envisat MIPAS and GOMOS and different atmospheric analyses": A. Gobiet et al. (published 27.02.2007, open until 24.04.2007); Comments being collected by CP.
"Validation of MIPAS-ENVISAT NO2 operational data": G. Wetzel et al. (published 02.03.2007, open until 27.04.2007); Comments being collected by CW.

Other papers with 'MIPAS' in the title in the Open Discussion phase, which may be adopted at a future meeting

" Validation of MIPAS HNO3 operational data": D. Y. Wang et al. (published 17.04.2007, open until 12.06.2007)
"Bias determination and precision validation of ozone profiles from MIPAS-Envisat retrieved with the IMK-IAA processor": T. Steck et al. (published 30.03.2007, open until 25.05.2007)

Summary of the March Monthly Report (F. Niro, ESRIN,

During March 2007 the MIPAS instrument performs extremely well, in fact we report only two instrument failures due to IDU errors. However the instrument was switched off during 16 – 18 March due to a Macro-Command (MCMD) transfer error. Furthermore a short unavailability (4min) was planned on 19th March in order to perform on-board time maintenance (see 2.2.2).

The instrument planning for the reporting month is hereafter summarized (see 2.2.1):

The instrument operates during 4 – 18 March in NOM mode in support to ECOWAR campaign; 3 orbits/day both ascending and descending tracks over Plateau Rosa (45.9°N, 7.7°E)
LOS sideways observations were planned for the first time over one full orbit on 8th and 27th March in order to investigate the roll mispointing
On 19th March special NOM mode observations with fixed azimuth angle were planned for testing purposes
Upper Atmosphere and Middle Atmosphere mode were planned during 22 – 23 March 2007 close to the Equinox. NOM operations were resumed on 24th March.

The instrument duty cycle during the reporting month was 49.29%, in line with the recommendation of Science Team and industry. The availability of the instrument was high (95.6% of the planned time) owing to the very good performance of the INT. The measurement segments not processed to L0 due to failures at the PDS were about 2.2% of the planned measurement time (see 2.2.4).

The monitoring of the instrument temperatures shows an increase of about 2K over the reporting month due to the seasonal variation of the instrument temperature. However a big jump of about 4K in the FCA temperature was detected after the MCMD transfer error of 16 March. This problem was already observed after a platform switch-off (see 2.3.1).

The cooler performs really well during this month, the vibrations were always well below the warning level of 8 mg. However we start to observe orbital dependent spikes in the compressor vibrations, these features are usually appearing in correspondence to the hottest period of the year (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 decontamination events. During the reporting month a slight increase of ADC max counts is observed linked to the seasonal variation (increase) of the instrument temperature (see 2.3.4).

The monitoring of the spectral correction factor shows a stable situation since the variations are of the order of 3 ppm over almost two years of operations, in particular the variations are due to noise (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% (see 2.4.3.1).

The analysis of the accumulated gain shows a steady increase of the gain with a constant rate and highlights the decontamination events throughout the mission. During the last months we observed a decreasing slope of the gain curve, showing that the detector is more and more ice-free (see 2.4.3.2).

The absolute mispointing error is stable around a value of -30mdeg. The seasonal variations of the pointing error are small and below the fixed threshold of 8mdeg (see 2.4.4).

The attempt to retrieve a roll mispointing from the sideways LOS measurements (planned on 8th and 27th of March) has failed since the number of measured stars was too few to retrieve any information. Sideways LOS will be routinely performed every two weeks from now on, therefore it is expected to have some information about roll mispointing in the future.

The long term monitoring of fringe count errors (FCE) for the RR mission was investigated this month. A statistical analysis was suggested during QWG#11 and it is reported in this MR, this analysis shows that the width of the statistical distribution of the FCE can be used as a measure of the INT performances. In fact the long term variation of the FCE statistical dispersion is highly correlated with the number of IDU velocity errors (see 2.4.5.1).

The long term monitoring of the detected spikes is reported in this MR. The presence of spikes on the scene IGM is detected by the L1 processor, these spikes are corrected in order to avoid artefacts in the spectrum. The number of spikes in channels A1, A2, B1 and B2 is increasing up to Dec 2006, while since Jan 2007 we observe a decrease. The channels C and D (the detector most affected by spikes) didn’t show any trend so far (see 2.4.5.2).

The level 0 NRT daily reports can be accessed at the following address:
http://earth.esa.int/pcs/envisat/mipas/reports/daily/Level_0_NRT/
The level 1b OFL daily reports can be accessed at the following address:
http://earth.esa.int/pcs/envisat/mipas/reports/daily/Level_1_OFL/

Oxford MIPAS meeting#116 17 Apr 07

Oxford MIPAS meeting#116
17 Apr 07