Oxford MIPAS meeting#140
03 Jun 08

Present

Oxford: Anu Dudhia, Jane Hurley, Luis Millan-Valle, Joanne Walker, Claire Waymark
RAL: Alison Waterfall

Instrument Status [Prev] [Next]

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

During Teresina campaign (28May-30Jun), aim to keep MIPAS in Nominal mode for days when orbit overpasses launch area (Brazil), so MA and UA mode observations are irregularly scheduled

Recent interruptions in data [ESA web-page]

From 21:27:56 13 May to 06:30:00 15 May - SPE (Signal Processing Electronics) Anomaly - known problem, not serious.

Anomalous Scanning

15th May included special "Volcanic Eruption" observation mode planned for 15th May to coincide with Chaiten, Chile but scanning for the remainder of the day was anomalous: UA scan pattern (172-42km in 35 steps) but with upper altitude set to NOM scan pattern (~70km) - effect is that scanning was from +70 to -60km (might actually be useful if anyone is interested in MIPAS spectra pointing at the earth's surface/cloud layer).

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

April Monthly Report [Prev] [Next]

April monthly report available on ESA web-site

[Summary]

L1B Data [Prev] [Next]

[L1B Data Coverage]

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

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

Only partial OFL data available for 7-9 May (following MIPAS switch-on) although full NRT data was produced. However (2nd June) remaining OFL data for 7-9 May now available.

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

[Oxford L2 Data Coverage]

Running MORSE to retrieve our own L2 data

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 30th Aprile
Processing all previous Apr/May/Jun 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: 15th May
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 30th May

QBO Signal in MIPAS N2O (AD)

N2O (and CH4) spring data at low latitudes shows clear separation into two values, alternating each year

[1mb,Equ] 2003,2005,2007 low values compared with 2004,2006,2008
[10mb, 20-65N] 2003,2005,2007 high values compared with 2004,2006,2008.

Presumably linked to QBO/SAO variations in atmospheric circulation

Cloud Retrievals (JH) [Prev] [Next]

Looking for techniques to distinguish between water and ice spectra for clouds with the same macrophysical parameters (Cloud top height, cloud top temperature and extinction)

Using Mie code, determined spectral regions where ice/water extinction coefficients are same/different
Next: try simple cloud-index type test looking at radiance ratios in different microwindows (from IMK Cloud Spectral DataBase) to see if ice/water can be separated
After: retrieve macrophysical parameters and look at retrieved extinctions in different microwindows - should be better than simple CI test using radiances in the since cloud-top height and cloud-top temperature variations are removed.

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

Compare day/night radiances from MIPAS MA mode with day/night differences calculated by RFM using current non-LTE model vibrational temperatures to identify deficiencies in non-LTE modelling

[Plot] shows CO2 transitions in A,AB,D bands (rows), with the left panels showing the individual spectral lines and the right panels showing the measured day/ngt ratios from 5 different days compared with the model (solid line) - all for mid-latitude conditions.
Full results will be written up as a Tech Note.

TES Limb Retrievals (CW) [Prev] [Next]

Attempting to use MORSE to retrieve pT,H2O,O3 and HNO3 from TES limb-spectra.

Now running MORSE to retrieve TES limb-data

NOy v N2O (JW) [Prev]

Using MORSE retrievals of NOy (HNO3, N2O5, NO2 - nighttime so can ignore NO) and N2O to construct correlation plots

[Plot] of NOy v N2O for

Major feature is a slope with gradient approximately -0.1 confirming that approximately 10% of N2O decomposes to produce NOy (remaining 90% produces N2).

Where slope breaks down (low values of N2O) - corresponds to polar vortex where denitrification and other processes dominate.

RAL Work (AW) [Prev]

Not much recent work with MIPAS data but starting to acquire, and read, IASI spectra from Eumetsat.

ACPD Papers [Prev] [Next]

Papers selected from the ACPD website for discussion

"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); Introduced by JW.
"How small is a small cloud?": I. Koren et al (published 28 Mar 2008, open until 23 May 2008); Comments submitted by JH. Discussion now closed
"4D-Var Assimilation of MIPAS chemical observations: ozone and nitrogen dioxide analyses": Q. Errera et al (published 22 Apr 2008, open until 18 Jun 2008); Comments being collected by LMV.
"Odin/OSIRIS observations of stratospheric NO3 through sunrise and sunset": C. A. McLinden and C. S. Haley (publihed 20 Mar 2008, open until 15 May 2008).; Comments were being collected by JW but discussion closed before anything was submitted.

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

"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 ?)
"Vertical profile of peroxyacetyl nitrate (PAN) from MIPAS-STR measurements over Brazil in February 2005 and the role of PAN in the UT tropical NOy partitioning": C. Keim et al. (published 09 Apr 2008, open until 04 Jun 2008)

Summary of April 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, a manual procedure will be used from now on in case of instrument anomaly. 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 the ftp rolling archive.
During the reporting month MIPAS performed very well, in fact only one IDU error was recorded, but the instrument was not available during 21 ? 22 April due to a planned OCM and from 30 April to 7 May due to the planned passive decontamination (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. Special in-flight calibrations (IF-16) were performed on 29 April just before the decontamination; similarly an IF-16 is planned for the 7 May just after the decontamination as required by the QWG. A more detailed description of the instrument planning for the reporting month can be found in ?2.2.1.
MIPAS weekly statistics are presented in this report for the whole RR mission. These weekly statistics 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).
During this month we noticed some anomalous L1 NRT products, in these products the field ?NUM_SWEEPS_PER_SCAN? in the SPH is wrongly filled with ?28? while the considered orbits are nominal (27 sweeps). The analysis has shown that the problem is related with IPF 4.67 and it will be corrected with the upcoming IPF 5.00, therefore no NCR is open at the moment. The corresponding OFL data are not affected by this problem (see $3.5.9).
The instrument temperatures slightly increase (1 ? 2 K) during the reporting month in line with the seasonal trend, in fact we are approaching the warmest period of the year for MIPAS (May-June) (see ? 2.3.1).
The cooler performs well during the reporting month; the vibrations were well below the warning level of 8 mg. However in the last month we observe an increase of the cooler vibrations due to the warmer instrument environment during this period of the year (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 increase 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. In the last weeks the slope of the curve increases slightly, this is nominal since we are approaching May, when the detector is more ice-contaminated. This situation will be solved with the planned decontamination of beginning of May (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:

http://earth.esa.int/pcs/envisat/mipas/reports/daily/Level_0_NRT/

The level 1b NRT daily reports can be accessed at the following address:

http://earth.esa.int/pcs/envisat/mipas/reports/daily/Level_1_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/

----------------------------------------------

************************************
Fabrizio Niro
- SERCO Spa -
Via Sciadonna 24,
00044 Frascati (RM), Italy
Tel: +39-06-94294311
fax: +39-06-9419426
e-mail : fniro@serco.it
************************************

Oxford MIPAS meeting#140 03 Jun 08

Oxford MIPAS meeting#140
03 Jun 08