Oxford MIPAS meeting#100
01 August 06

Present

Oxford: Anu Dudhia, Don Grainger, Chiara Piccolo, Joanne Walker, Claire Waymark,
IAA: Manuel Lopez-Puertas

Currently in the middle 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].

Software Updates (L1C) [Prev] [Next]

l1c.pro has been updated: new version 28JUL06

Fix bug in evaluating Cloud Index
Recognise the various special modes under Reduced Resolution operations

L1B Data (AD) [Prev] [Next]

L1B coverage maps showing locations and operating mode of RR L1B data since Jan 2005 - probably complete for 2005 but need updating for 2006.

ESRIN-circulated listing of all RR data archived up to 18JUL06: [XLS] [HTML]
Latest data is 28JUN06, so about 3 weeks behind "live" data.

EQUAL (AD) [Prev]

EQUAL is a project to validate Envisat (ie MIPAS, GOMOS and SCIAMACHY) Ozone and Temperature profiles using a network of lidars.

2005 Annual Report now published: http://earth.esa.int/pcs/envisat/calval_res/2005/
MIPAS validation results aren't included in the report but will appear in the pT and O3 MIPAS validation papers.

HiRDLS Comparisons (CW) [Prev] [Next]

Using HIRDLS v integrated MIPAS radiance profiles to estimate altitude offset between two instruments.

ACE/ODIN Comparisons (CP) [Prev] [Next]

Using ACE and ODIN measurements for validation of ESA MIPAS L2 data

Continuing to iterate with Ugo Cortesi to provide plots for O3 validation paper

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

pT microwindows for reduced resolution, 27 sweeps (PT__0331-335) have been observed to produce a spike in the temperature retrieval at the 21km nominal altitude (ie, 11th tangent point from bottom of scan) when using the IFAC processor - thought to be caused by the discontinuity between using the CO2 laser lines (>900cm-1) for low altitudes with longer wavelength MWs (<800cm-1) for higher altitudes.

Attempts to add new microwindows at longer wavelengths spanning 21km altitude (342,343) do not solve the problem - in fact may make things worse

Completely new pT MW selection being attempted, this time 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. Currently first 5 MWs found are

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

In the process of generating LUTs for these MWs before sending to IFAC for testing with the ORM.

N2O Anomaly Mar03 (AD) [Prev]

Anomalously high N2O concentrations reported in ESA MIPAS L2 data around 7-8 March and 13-15 March 2003

EO Helpdesk has issued the following warning:

Please be informed that we have detected an anomaly in the re-processed MIPAS Level 1b and Level 2 dataset.
The anomaly concerns 34 orbits in the period 08-15 March 2005 (see attached listings: [Level 1] [Level 2])
The investigations traced back the problem to the usage of an outdated auxiliary file.
Corrective actions are currently being carried out.
The products will be reprocessed and provided on the D-PAC ftp-server soon.

Impact of Reduced Resolution (JW) [Prev]

Simple theory predicts that, when the spectral resolution is reduced by factor M molecules with individual line features will have S/N degraded by root(M)

Simulations with CO spectral features show that degradation is actually not as bad as this
Reason is that CO lines are actually quite broad relative to the MIPAS AILS - (root(M) argument strictly applies to "delta-function" line shapes). [Plot]
Coupled with additional measurements at 1.5km, it should be possible to retrieve CO @ 3km vertical resolution with similar precision using 17FR and 27RR measurements (at least at low altitudes).

TES Retrievals (CP) [Prev] [Next]

Adapted MORSE to run TES limb retrievals using specially selected microwindows for joint pT+H2O+O3 retrieval, followed by HNO3

Processing 22Sep04, but no matching MIPAS data for that day for comparison (although some 17RR data for 16-17th Sep)
Some problems identifying cloudy/cloud-free scenes - using equivalent of MIPAS B-band Cloud Index but TES team use a different algorithm
Results for pT and O3 look reasonable.

Solar Proton Event (CW/MLP)

Plan on using MORSE to retrieve all available MIPAS data from Jan 05, including that taken in MA and UTLS1 modes, to try and capture evolution of atmosphere following SPE.

NO Retrieval (JW/MLP) [Prev] [Next]

Derive zonal mean NO for selected days by comparing day/night difference in retrieved NO2 & N2O5

[Plot - top IMK/IAA, bottom Oxford] Comparison with IMK/IAA non-LTE retrieval of NO looks reasonable
However, there seems to be a persistent hemispheric asymmetry - more NO in northern hemisphere at 40 km even at equinoces.
Comparison with HNO3 shows no particular asymmetry, and HNO3 peak is in any case at lower altitude, so cannot be explained by simple NOy partitioning.
Other explanations?

Non-LTE (MLP)

Working on modelling non-LTE emissions in MIPAS D-band for CO and N2O.

Oxford MIPAS meeting#100 01 August 06

Oxford MIPAS meeting#100
01 August 06