Oxford MIPAS meeting#101
15 August 06

Present

Oxford: Anu Dudhia, Don Grainger, Jane Hurley, Chiara Piccolo, Joanne Walker, Claire Waymark,
IAA: Manuel Lopez-Puertas
RAL: Alison Waterfall

Instrument Status [Prev] [Next]

Currently getting towards the end of a month-long period (21Jul-21Aug) of measurements in support of AMMA campaign (W.Africa) - 3 orbits on, 4 orbits off, UTLS1 mode.

Current version of Mission Planning Document (2006 up to Aug25) [XLS] [HTML].
New Web Page listing reduced-resolution measurement modes
Envisat Web-Site

July Monthly Report (AD) [Prev] [Next]

MIPAS monthly report for July is now available

[Summary]. No major changes from previous month.
Full report downloadable from http://earth.esa.int/pcs/envisat/mipas/reports/monthly/

L1B Data (JH) [Prev] [Next]

L1B coverage maps showing locations and operating mode of RR L1B data since Jan 2005 - now updated to end of Jun 2006

ESRIN-circulated listing of all RR data archived up to 18JUL06: [XLS] [HTML]

L2 Data Anomalies (CP) [Prev] [Next]

Precision analyses (see below) have highlighted a couple of anomalies with the L2 data

pT covariance values are sometimes v.small and negative (eg MIP_NL__2PPDPA20040126_021251_000060262023_00390_09963_3263.N1) - this may be the same anomaly as identified in section 3.9.3 of the July monthly report
2002 data often missing near S.Pole, eg 25 Jul 02

HIRDLS Comparisons (CW) [Prev] [Next]

Using MORSE-retrievals of MIPAS data as validation for HIRDLS.

Comparing Zonal Mean MIPAS (top), HIRDLS (middle) and differences (bottom) for 28Jan05: pT looks very similar, O3 has some significant differences.

MIPAS Precision (CP) [Prev] [Next]

Investigating MIPAS L2 precision values by comparing scatter between retrieved profiles where orbital tangent tracks intersect with scatter predicted by retrieval SD

Limiting comparisons to 6hours time difference, 100km horizontal distance, this produces regular matches at two latitudes, near the poles.
Plots show ratio of observed/predicted scatter for each species in S.Polar (Black Triangle) and N.Polar (Red Square) region as a function of month (using 5 days/month), (a) [Whole profile] (b) [Stratosphere (ie 15km & above)] (c) [Troposphere (ie 6,9,12km)]
Removing troposphere, scatter is generally consistent with predicted errors apart from Temperature (larger) and HNO3 (smaller).

RR27 pT Retrieval (AD) [Prev] [Next]

New pT MW selection now complete: assuming that contaminating species (mainly O3, H2O) are known to within their retrieval errors rather than climatological uncertainty. This only includes one laser band MW and has no discontinuity at 21km.
10 selected MWs as follows:

Microwindow Wavenumber Range Altitude Range
PT__0351 769.9375 772.9375 7.5 54.0
PT__0352 719.3750 722.3750 31.0 70.0
PT__0353 759.8750 762.8750 9.0 46.0
PT__0354 944.2500 947.0625 6.0 25.0
PT__0355 755.0625 757.4375 9.0 43.0
PT__0356 739.1875 742.1875 25.0 70.0
PT__0357 766.8750 769.8750 7.5 54.0
PT__0358 715.2500 718.2500 19.5 58.0
PT__0359 763.8125 766.8125 7.5 27.0
PT__0360 691.5625 694.2500 27.0 54.0

First 5 MWs (351-355) sent to IFAC for testing with the ORM.

Cloud Parameters (JH) [Prev] [Next]

Microwindow	Wavenumber Range	Altitude Range
PT__0351	769.9375	772.9375	7.5	54.0
PT__0352	719.3750	722.3750	31.0	70.0
PT__0353	759.8750	762.8750	9.0	46.0
PT__0354	944.2500	947.0625	6.0	25.0
PT__0355	755.0625	757.4375	9.0	43.0
PT__0356	739.1875	742.1875	25.0	70.0
PT__0357	766.8750	769.8750	7.5	54.0
PT__0358	715.2500	718.2500	19.5	58.0
PT__0359	763.8125	766.8125	7.5	27.0
PT__0360	691.5625	694.2500	27.0	54.0

Investigating retrieval of cloud paramters from MIPAS spectra.

Is it reasonable to use spectra from two adjacent tangent heights to retrieve single set of cloud parameters? I.e. is there a significant overlap in the cloud volume sampled by both cases?
Will generate a plot to investigate this, although we can say for now that it is more valid with the RR27 scan pattern than FR17 (less satellite distance between scans plus 1.5km tangent height displacement instead of 3km).

GOME & ECMWF Comparisons (AW) [Prev]

Continuing with work for MIPAS O3 and pT validation papers using GOME and ECMWF data.

CF4 Retrievals (CP) [Prev]

Retrieving zonal mean CF4 using MORSE coupled with a kalman filter within latitude bins. CF4 is a very long-lived tracer. While its distribution in the troposphere and lower stratosphere is expected to be quite uniform, its distribution at higher altitudes is less well-known.

Zonal mean structure shows minima at mid-latitudes [Plot]
Comparison with equivalent CH4 and N2O fields suggests that this is real and associated with descent

Middle Atmosphere Mode (AD) [Next]

Started on microwindow selection for MA mode observations (29 sweeps from 18-102km @ 3km steps). Intention is to use these to retrieve mesospheric data taken Jan 10-15 2005.

Noctilucent Clouds (MLP) [Next]

Attempting to detect the presence of NLC in MIPAS spectra by integrating radiance from 770-902cm-1

Detect radiance enhancements at correct altitude/latitude/season, but spectral signature not as expected

Also note that integrated radiance where no cloud is present is still almost always positive (a few nW, which is <10% NESR), not ~zero as might be expected. Radiometric Offset problem?

ACPD Papers [Next]

To try and promote the Atmospheric Chemistry and Physics Discussion concept, as well as keep up-to-date with current research, for each meeting a different person will introduce a paper selected from the ACPD website and pass it around for comments after which they will post our collective thoughts on the discussion web-site.

The chosen paper for this meeting, introduced by CP, is "Ground-based remote sensing of HDO/H2O ratio profiles: introduction and validation of an innovative retrieval approach" by M. Schneider et al., submitted 27.06.2006.
Next meeting's paper, to be introduced by CW, will probably be " Variability and trends in total and vertically resolved stratospheric ozone", by Brunner et al., submitted 12.07.2006 (unless she spots something of more interest in the meantime)

Summary of July Monthly Report (F. Niro, ESRIN)

The MIPAS instrument performs really well during the reporting month; in fact only 4 instrument anomalies were recorded (IDU velocity error). As a result of this new operation stability the MIPAS Science Team in agreement with industry and ESA decided to increase the duty cycle of the instrument by slightly change the mission planning; in particular starting from this month the following corrective actions were implemented for increasing the duty cycle:

Planning of 6 orbits/day during mission campaign instead of 4 orbits/day, increasing the duty cycle from typically 30% to 42%.
Reduce the frequency of the IDU re-initialization from once per orbit to one every three orbits during the 3 days-on/4 days-off operations

During July 2006 the instrument operated with a duty cycle of about 34%, this seems to disagree with respect to what stated in the previous bullet; nevertheless this low duty cycle is due to two planned long mission interruptions (11 days in total), these two periods were explicitly planned in order to have the instrument in the best condition for the kick-off of AMMA campaign.
The instrument operated during July with the following plan:

NOM modes were planned during 4 – 7 and 12 – 13 July
UTLS-1 mode were planned starting from 21 July in support to AMMA campaign with 6 orbits per day, both in ascending and descending track over Central-West Africa (20°N-20°S, 25°W-25°E)

We already pointed out that MIPAS performs really well during this month; in fact the instrument availability is equal to 98.6 % of the planned measurement time. The missing gaps due to PDS failure were very high (about 17% of the planned time) due to a major anomaly in the data acquisition and downlink. The anomaly was due to the HSM input module; as a result no MIPAS level0 could be generated from 27 July to 3 August 2006. The problem was resolved the 3rd August with a HSM module reset.
The monitoring of the instrument temperatures continued nominally this month. We observe an overall stability of all the devices temperatures, the variation over the entire month being less than 2K (see § 2.3.1).
The cooler performance was closely monitored on a daily and monthly basis. The cooler seems to perform really well, even though we observed some orbit-dependent spikes that reach the limit of 8 mg at their maxima. These spikes that start to appear during May 2006 seem to be reduced during the reporting month (see § 2.3.3.1).
The spectral correction factor long term monitoring of the RR mission (since Aug 2004) shows a stable situation since the variations are of the order of 3 ppm over almost two years of operations, a decreasing trend can be observed along the mission, this is nominal and is due to the aging of the laser metrology (see § 2.4.2).
The gain calibrations were carried out nominally during the reporting period on a weekly basis including the dissemination of the related ADF. The gain weekly increase remains stable, the maximum of gain increase in the band A between two consecutive disseminated gains remains below the acceptance criterion of 1% (see § 2.4.3.1).
The long term gain monitoring since the last decontamination (June 2005) is presented in this MR. This monitoring will help the planning of the future decontamination activity (to be expected at least twice per year). We can observe that the gain increase looks linear with time after the decontamination induced by the PLSOL of April. Nowadays the gain in the band A is about 17% higher (at its maximum) with respect to the first gain disseminated after the decontamination of June 2005 (see § 2.4.3.2).
The mispointing long term monitoring shows a steady situation; in fact during the last year the relative bias seems to be stable around a value of few mdeg. To be noted that the last disseminated LOS ADF was on March 2005 (see § 2.4.4).
The level 1 quality monitoring of the OFL products created at D-PAC is on going in parallel with the mission. The level 1b daily reports can be accessed at the following address:

http://earth.esa.int/pcs/envisat/mipas/reports/daily/Level_1_OFL/.

The long term monitoring of fringe count errors (FCE) for the RR mission is shown in this MR; this analysis is based on the L1b products generated OFL at D-PAC. This monitoring aims at the verification of the stability of FCE over time; furthermore this analysis is useful in order to verify if any correlation exists with the INT performances degradation. So far no correlation can be appreciated from this analysis.
A quality control of L2 RR OFL products processed with the latest IPF 4.65 (Aug – Sept 2004) was carried out at ESRIN, showing an overall good quality of the level 2 data. To see all the L2 OFL daily reports of RR mission follow the link below:

http://earth.esa.int/pcs/envisat/mipas/reports/daily/Level_2_OFL/

Oxford MIPAS meeting#101 15 August 06

Oxford MIPAS meeting#101
15 August 06