Oxford MIPAS meeting#142
15 Jul 08

Present

Oxford: Anu Dudhia, Luis Millan-Valle, Joanne Walker

Instrument Status [Prev] [Next]

Operating continuously since 1st Dec 2007 in standard cycle of 8 days NOM, 1 day MA, 1 day UA.

5-7 Jul 08: 3 full days of "Noctilucent Cloud" Mode observations (basically MA mode with extra scans around 80-85km)

Recent interruptions in data [MIPAS Availability]

15 Jul 2008 From 00:48 until 04:30 "This was an IDU error, triggered by the change of scenario and the subsequent re-initialization of the slides (start-up failure), the IDU anomaly was recovered at ESOC without any problems" - F. Niro (ESRIN), 15th July

General Information

Mission Planning Document for 2008 [XLS] [HTML].
MIPAS Mission Plan v4.3 (March 08) [DOC] [PDF]
Currently defined measurement modes
Envisat Web-Site

June Monthly Report [Prev] [Next]

June monthly report available on ESA web-site

[Summary]

Anomalous Scanning Aug06 [Prev]

It has just been noticed (during Oxford L2 processing) that in the NOM mode data taken from 6-8 Aug 2006 the tangent altitudes are around 15-20km below their correct heights.

It looks as if the altitude offset for the UTLS1 mode has been used with the NOM mode scan pattern
May be useful if anyone needs multispectral observations of the earth's surface!
Details in June 2008 monthly report, section 3.5.11.

L1B Data [Prev] [Next]

[L1B Data Coverage]

"Near Real Time" (NRT) data available on Kiruna or ESRIN ftp sites ~ hours after acquisition.

No apparent problems

"Off-line" (OFL) L1B data available on D-PAC ftp site approximately 2 weeks after acquisition.

Sporadically available from 26-29 June - missing many orbits that were available in NRT
Recent problems getting ftp connection (unlike NRT data sites)
D-PAC archive now being progressively compressed (gzip) from 2002 onwards but not yet apparent in recent L1B data

Oxford L2 Processing (AD) [Prev] [Next]

[Oxford L2 Data Coverage]

Running MORSE to retrieve our own L2 data (ESA species plus CFC-11,CFC-12,N2O5,ClONO2 and CO)

Processing all new "off-line" data currently with a lag of around 3 weeks (2 weeks for L1B data to appear, 1 week to process L2 locally) - most recent day 24th June
Processing all previous Aug data (2002-2007) in parallel to provide comparison with recent data and eventually providing a complete L2 dataset - most recent day completed for all years: 31st July
Processing NOM mode NRT data - same L2 algorithm but restricted to pT, H2O and O3. Usually available a couple of days after acquisition. - most recent day 13th July

Antarctic Winter (AD) [Prev] [Next]

From the Oxford L2 [trend plots] for 65S-90S at 10mb

[Temperature] seems to have stabilised at around 190K average since the end of June - a few K cooler than in previous years (185-190 K in 80S-90S region)
[HNO3] partly recovered from unusual drop in May but still lower than previous years and continuing to drop.
[CFC-11] Still high at the end of June rising in line with falling temperatures - if the values stabilise in subsequent days (following the levelling off of the temperature drop) this will be more evidence that this is related to the temperature dependence of the absorption coefficient tabulation.

Residual Spectra (JW) [Prev]

Plan to start updating the Monthly Mean Residual plots for the RR data (and in anticipation of new ESA L2 data)

Currently converting original IDL software to use low-level BEAT routines to extract residual spectra for each microwindow

Non-LTE Radiances (LMV) [Prev] [Next]

Writing up a Tech Note summarising differences between observed day/night differences in MIPAS MA mode spectra and the expected differences from the non-LTE models used for microwindow selection and error budget calculations.

Now extending analysis to other species (was just CO2)

ACPD Papers [Prev] [Next]

Papers selected from the ACPD website for discussion

"Comparison of CMAM simulations of carbon monoxide (CO), nitrous oxide (N2O), and methane (CH4) with observations from Odin/SMR, ACE-FTS, and Aura/MLS": J. J. Jin et al (published 09 Jul 2008, open until 03 Sep 2008); Introduced by AD.
"Mesospheric N2O enhancements as observed by MIPAS on Envisat during the polar winters in 2002-2004": B. Funke et al (published 03 Jun 2008, open until 29 Jul 2008); Comments being collected by LMV.
"Nitric acid in the stratosphere based on Odin observations from 2001 to 2007 - Part 1: A global climatology": J. Urban et al (published 26 May 2008, open until 21 Jul 2008); Comments being collected by JW.

Other MIPAS-related papers in the Open Discussion phase, which may be adopted at a future meeting

[none at present]

Summary of June Report

MIPAS is back to full-time mission (100% duty cycle) since 1st December 2007.

Since 3 March 2008 the auto-recovery procedure implemented at ESOC was dismissed and replaced with a manual procedure. As a result the re-initialization gap is no longer present in the MIPAS data.

The MIPAS level 1 NRT processing was restarted on 1st February 2008 at Kiruna and ESRIN stations, the products are available via ftp rolling archive.
A problem in old MIPAS measurements was recognized by Anu Dudhia (OU) and reported to ESRIN. The anomaly consisted in a wrong scan pattern used during 6 ? 8 August 2006. The problem was most likely due to the usage of an incomplete set of CTI, in particular the commanded altitude spacing and number of sweeps was the one of NOM, while the starting altitude was the one of UTLS-1. As a result the last 10 sweeps measured during these days have altitude below Earth surface and cannot be used for atmospheric studies (see ?3.5.11).
An anomaly was detected in one L1 product generated OFL at D-PAC center (orbit #33019). The problem was an anomalous high NESR level in band A. The problem was not observed in the corresponding NRT data, although they used the same set of auxiliary files. Investigations are on-going to understand the root cause of the problem (see ?3.5.12).
During the reporting month MIPAS performs extremely well; in fact no instrument anomaly was observed due to IDU error, however MIPAS was unavailable from 26 Jun 03:02 to 27 Jun 09:20 due to a known anomaly in the Communication Area (CCA). This anomaly was solved with manual intervention at ESOC. MIPAS was not available from 30 Jun 22:05 to 1st Jul 07:00 for a planned Orbit Control Manoeuvre (OCM).
Special Planning was commanded from 28 May 2008 to 30 June 2008 in support to the Teresina Campaign. The rationale of the planning is to have as much as possible MIPAS in NOM mode over the campaign area (Brazil), therefore the UA and MA mode were irregularly planned, furthermore special sideways NOM scans were placed over the launch site. A more detailed description of the instrument planning for the reporting month can be found in ?2.2.1.
MIPAS weekly statistics since 2005 show the improvement of the instrument performances and the increase of duty cycle in the last months. The availability of L1 NRT products is also presented in this paragraph (see ? 2.2.4).
The availability of L1 OFL products with respect to the expected time is stable around a value of 95% in the last months (see ?2.2.5).
The instrument temperatures slightly decrease during the reporting month in line with the seasonal trend (see ? 2.3.1).
The cooler performs well during the reporting month; the vibrations were 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 start to decrease following the variation of the instrument temperature (see ?2.3.4).
The monitoring of the spectral correction factor shows a slight decreasing trend; nevertheless 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 year 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. Less and less stars are available in the last months for the LOS calibration, as a result the mispointing estimation is becoming less precise (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 periods of the MIPAS mission (June 2005 and February 2006), while during the last months no clear correlation can be found (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:

Oxford MIPAS meeting#142 15 Jul 08

Oxford MIPAS meeting#142
15 Jul 08