Oxford MIPAS meeting#124 (14 Aug 07)

During the reporting month MIPAS performances were really satisfactory; indeed only 2 instrument anomalies were recorded due to IDU errors. MIPAS was unavailable from 16th to 17th July due to a planned OCM, furthermore a problem on the communication area (CCA) determines an instrument switch-off from 20th to 21st July (see 2.2.2).
The instrument planning for the reporting month is hereafter summarized (see 2.2.1):

- The duty cycle was raised up to 80%
- The scenario for summer time was planned it consists on the following sequence of measurements: 3 days NOM + 2 days NLC + 3 days NOM + 2 days off. Starting from 28th July the baseline scenario was resumed: 4 days NOM + 1 day MA + 3 days NOM + 2 days off
- In-flight calibration (IF6, IF9, IF10, IF11) were planned on 21st July
- Pointing test in nominal mode were planned on 21st July, they consist on a series of orbits in NOM mode with fixed azimuth angle at 75°, 80°, 90° 100° and 110°

All the planned measurements were acquired a part for the pointing tests that were partially lost due to the instrument switch-off.
The availability of the instrument was high (95.95 % of the planned time) owing to the good performances of the interferometer. The measurement segments not processed to level 0 due to failures at the ground segment were less than 0.5% of the planned measurement time (see 2.2.4).
The long term analysis of MIPAS L0 NRT availability shows the increased duty cycle since April 2006 and highlights the improved instrument performances (see 2.2.4.2).
The instrument temperatures are stable over the reporting month with variation in the range of 1K (see 2.3.1).
The cooler performs well during the reporting month; the vibrations were always below the warning level of 8 mg. The instrument switch-off occurred on 20th July determines a decrease of the compressor acceleration by about 1mg (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 decrease in line with the seasonal trend of the instrument temperature (see 0).
The monitoring of the spectral correction factor shows a slight decreasing trend; however the variations over almost two years of operations are really small (around 3 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 shows a steady increase of the gain with a constant rate and highlights the decontamination events throughout the mission. During the last year 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 -25mdeg. The seasonal variations of the pointing error are small and below the fixed threshold of 8mdeg. No results are available from the sideways LOS calibration measurements due to the very poor star signal acquired (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 fact the long term variation of the FCE statistical dispersion is highly correlated with the number of IDU errors (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 very 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:

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#124
14 Aug 07

July Monthly Report - Summary (F.Niro, ESRIN)

Oxford MIPAS meeting#124 14 Aug 07

July Monthly Report - Summary (F.Niro, ESRIN)

Oxford MIPAS meeting#124
14 Aug 07