Oxford MIPAS meeting#131
15 Jan 08
During the reporting month MIPAS performed really well; in fact only 2 instrument anomalies occurred due to IDU errors (see §2.2.2). • The instrument planning for the reporting month is hereafter summarized: o The duty cycle was set to 80% o The Baseline scenario was planned, it consists of the following measurements: 3 days NOM + 1 day MA + 1 day UA + 3 days NOM + 2 days off • A more detailed description of the instrument planning for the reporting month can be found in §2.2.1, see in particular Table 1. • The availability of the instrument was high (97.8 % of the planned time) due to the good performances of the interferometer. The measurement segments not processed to L0 due to failures in the PDS were about 0.6% of the planned measurement time (see § 2.2.4). • The long term analysis of L0 data availability shows the increased duty cycle since April 2006 and highlights the improved instrument performances in the last months (see §2.2.4.2). • In this report we present the long term availability of L1 consolidated data in the D-PAC server. We can see that the availability of L1 products with respect to the expected time is approaching 100% in the last months (see §2.2.5). • The instrument temperatures are stable over the reporting month, the variations being included in 1K (see § 2.3.1). • The cooler performs well during the reporting month; the vibrations were always 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 remain stable (see §2.3.4). • The monitoring of the spectral correction factor shows a slight decreasing trend; however 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 months 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 (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 period of the MIPAS mission (June 2005 February 2006), while in ENVISAT MIPAS Monthly Report: November 2007 issue 1 revision 0 - 15 Dec 2007 ENVI-SPPA-EOPG-TN-07-0078 page 5 the last months with the improved instrument performances no clear correlation can be highlighted (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 still really 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/
