Oxford MIPAS meeting#132
29 Jan 08

Present

Oxford: Anu Dudhia, Jane Hurley, Claire Waymark, 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.

Currently starting new NOM sequence

Mission Planning Document for 2008 [XLS] [HTML].
Currently defined measurement modes
Envisat Web-Site

December Monthly Report [Prev] [Next]

December monthly report available on ESA web-site

[Summary] (received 16 January)

L1B Data (JH) [Prev] [Next]

[L1B Data Coverage] - updated as far as to Dec 31st

L1B data available on ESA server approximately 2 weeks after acquisition

There has been a 1 week interruption in new L1B data appearing on the ESA ftp site, but (today) it seems to have resumed from where it left off (orbit 30607, 7Jan08)
At the recent QWG Meeting it was mentioned that 'near-real-time' L1B data would also soon be available.

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

Running MORSE to retrieve our own L2 data

[Oxford L2 Data Coverage] - most recent day: 07 Jan 08

[Recent & Long-Term Trends] - most recent month: Dec 07

Processing all new data currently with a lag of around 2½ weeks (2 weeks for L1B data to appear, ~2-3 days process L2 locally) - although now an extra week behind due to interruption in L1B availability.
Processing all previous Dec/Jan/Feb data (2002-2006) in parallel to provide comparison with recent data

Polar Stratospheric Clouds (JH) [Prev]

Trying to use SVD/macroscopic parameter retrieval to distinguish different types of PSC

Distinguishing type Ia PSCs (with "NAT bump") relatively straightforward using SVD, but equally straightforward using IMK Cloud-index method.
Distinguishing type Ib and II more difficult - IMK use cloud-index, which basically seems to be an optical thickness criterion, however macroscopic retrieval parameters Cloud Top Temperature and Cloud Optical Thickness should provide a better discrimination (assuming that Type II (ice) PSCs are colder and thicker)

CO Retrievals (JW) [Prev] [Next]

Investigating how to incorporate non-LTE effects into a practical (i.e. operational) scheme to retrieve CO

Currently attempting to tune the vibrational temperature a priori covariance to provide better constraint on joint CO-VT retrieval
Writing up results as an ACPD paper

MIPAS - TES Radiance Comparisons (CW) [Prev] [Next]

Comparing MIPAS and TES limb-viewing radiances from 28 Jan 2005 (one of the few days when TES and MIPAS were both taking limb-view observations)

Still rewriting code to handle new-format TES data

2007/8 Arctic Winter (AD) [Prev] [Next]

From the [Recent Trend] plots of Oxford L2 data for Oct/Nov/Dec/Jan 10mb, averaged from 65N to 90N for 2007 (black) compared to recent years:

[Temperature] after a slight warming at the end of December, unusually cold temperatures have been maintained through the start of January (<200K, cf 220-230K in previous years)
[NO2] and [N2O5] concentrations about half that of previous years
[ClONO2] & [HNO3] higher than normal, consistent with expected temperature dependence of partitioning of odd-nitrogen between active and reservoir species
Since the beginning of January [O3] has been slightly lower than previous years (although due to previous years O3 increasing at this time rather than this winter's O3 decreasing)
Passive tracers such as [CH4] and [N2O] are unusually low, and [H2O] unusually high, suggesting strong descent (also consistent with cold temperatures).

MIPAS QWG-15 Meeting (AD/JH) [Prev] [Next]

ESRIN, 23-25 Jan 2008

[Official minutes] (26Feb08)

[Notes] from JH
[AD Presentation] L2 Improvements
[AD Presentation] Recent MIPAS Data
[JH Presentation] Optimising CI microwindows & cloud macroscopic parameter retrieval

ACPD Papers [Prev] [Next]

Papers selected from the ACPD website for discussion

"Modelling of cirrus clouds - Part 1: Model description and validation": P. Spichtinger and K. M. Gierens (published 11 Jan 2008, open until 07 Mar 2008); Introduced by JH
"Measurement of the water vapour vertical profile and of the Earth's outgoing far infrared flux": L. Palchetti et al. (published 10 Dec 2007, open until 04 Feb 2008); Comments being collected by LMV.
"Inversion analysis of carbon monoxide emissions using data from the TES and MOPITT satellite instruments": D. B. A. Jones et al (published 05 Dec 2007, open until 30 Jan 2008); Comments being collected by JW.
"Dependence of cloud fraction and cloud top height on surface temperature derived from spectrally resolved UV/vis satellite observations": T. Wagner et al. (published 23 Nov 2007, discussion now closed); Comments submitted by JH (although may not have appeared on web-site)

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

"Technical Note: Continuity of MIPAS-ENVISAT ozone data quality from full- to reduced-spectral-resolution operation mode": S. Ceccherini et al. (published 16 Jan 2008, open until 12 Mar 2008).
"Validation and data characteristics of methane and nitrous oxide profiles observed by MIPAS and processed with Version 4.61 algorithm": S. Payan et al. (published 17 Dec 2007, open until 11 Feb 2008).

Summary of MIPAS December Report (F.Niro, ESRIN)

MIPAS is back to full-time mission since almost three years of non continuous operations. The duty cycle was raised to 100% starting from 1st December 2007 as a result of the very stable performances of the interferometer. The actual duty cycle for the reporting month is around 82% due to two platform switch-off planned for an OCM and a memory maintenance activity.
During this first month of full-time operations MIPAS performed well, even though a slight increase of IDU start-up failures were observed. This increase was expected due to the increase of time in operation; however the number of anomalies for the reporting month (4) is still acceptable. The IDU performances will be closely monitored in the next months in order to verify the response of the system to this enhanced duty cycle (see ?2.2.2).
The Baseline scenario for 100% duty cycle was planned; it consists of the following schema: 8 days NOM + 1 day MA + 1 day UA, furthermore special Aircraft Emission modes were planned starting from 31st December. A more detailed description of the instrument planning for the reporting month can be found in ?2.2.1.
The availability of the instrument was slightly lower than previous month (91.4% of the planned time) due to the increased number of IDU anomalies (4) and the ICU format header error. The measurement segments not processed to L0 due to failures in the PDS were about 2.2% 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 year (see ?2.2.4.2).
The availability of L1 D-PAC products with respect to the expected time is approaching 100% in the last months (see ?2.2.5).
The instrument temperatures are stable during the reporting month, the variations are in the range of 1 ? 2 K (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 slightly 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. The gain factor decreases by about 0.5% after the platform switch off occurred during 3 ? 5 December (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. 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 period of the MIPAS mission (June 2005 February 2006), while in the last months, with the improved instrument performances, 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:

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#132 29 Jan 08

Summary of MIPAS December Report (F.Niro, ESRIN)

Oxford MIPAS meeting#132
29 Jan 08