Oxford MIPAS meeting#122 (17 Jul 07)

During June 2007 the MIPAS instrument performs really well, in fact only 3 instrument unavailabilities were recorded due to IDU errors. Furthermore the instrument was switched off the first week of the reporting month for a passive decontamination (see 2.2.2).
The instrument planning for the reporting month is hereafter summarized (see 2.2.1):
- A passive decontamination was planned from 29th May to 6th June.
- The baseline scenario for 60% duty cycle was planned, it consists in the following sequence of measurements: 1 day MA + 3 days NOM + 2 days off + 2 days NOM + 2 days off
- Around the 21st June the baseline planning for the solstice period with 60% duty cycle was planned, it consists in the following sequence of measurements: 1 day UA + 1 day MA + 3 days NOM + 2 days off + 1 day NOM + 2 days off
- The availability of the instrument was high (97.2 % 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).
- In this MR a long term statistics of the L0 products availability is presented and will be updated in the future reports. This statistics shows the increased duty cycle since April 2006 and highlights the improved instrument performances during the last year (see 2.2.4.2).
- The anomalous level 1 products of 18th April 2007 were reprocessed at D-PAC, the list of reprocessed data was provided to the QWG and it is reported in the Appendix E (see 3.5.7).
- The monitoring of the instrument temperatures shows that after the decontamination all the instrument temperatures were reduced by about 1K and their values remain stable over the reporting month (see 2.3.1).
- The cooler performs well during the reporting month; the vibrations were always below the warning level of 8 mg. After the passive decontamination we noticed a significant improvement of all the cooler parameters, namely a reduction and a stabilization of the compressor acceleration level and of the cooler temperatures (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 remain stable due to the reduction of the instrument temperature after the decontamination (see 2.3.4).
- The monitoring of the spectral correction factor shows a slight decreasing trend, the variations over almost two years of operations are really small (about 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 below the acceptance criterion of 1%/week a part from the effect of the decontamination that causes a gain decrease of about 6% (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. The decontamination at the beginning of June determines a decrease of the slope of the gain curve due to the improved cooler performances (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) for the RR mission is presented in the MR. This analysis shows that the width of the statistical distribution of the FCE can be used as a measure of the IDU 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 is reported in this MR. The presence of spikes in the scene IGM is detected by the L1 processor, these spikes are corrected in order to avoid artefacts in the spectrum. The number of detected spikes in channels A1, A2, B1 and B2 is varying with time with some peaks probably related to variation in the solar activity. The channels C and D (the detector most affected by spikes) didn’t show any trend so far. However the frequency of detected spikes is still 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#122
17 Jul 07

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

Oxford MIPAS meeting#122 17 Jul 07

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

Oxford MIPAS meeting#122
17 Jul 07