Oxford MIPAS meeting#69
01 Feb 05

Present

Oxford: Alastair Burgess, Anu Dudhia, Don Grainger, Gareth Thomas, Claire Waymark, Iris Yiu
RAL: Jolyon Reburn, Martin Juckes
U.Bologna: Enzo Papandrea

Instrument Status [Prev] [Next]

Some details on the Envisat Web-Site including Instrument Availability web-site

Instrument should have completed January campaign testing out new modes at @0.0625cm^-1 resolution but no news received.
Major Aura validation campaign was also run during January
GOMOS switched off since 24th January due to a major anomaly with the steering front mechanism.

L1 Data [Prev] [Next]

[Listing of current BADC Archive of reprocessed L1B Data]

Bianca Dinelli (IFAC) has queried the existence of repeated files covering the same orbit (eg 9345, 9359) - apparently all processed with the same version of software. How do we know which is the "correct" one?
Note that these duplicates are indicated as "x2" "x3" etc in the above listing
Niels Bormann (ECMWF) asks if there is any simple method of identifying from the L1B data which scans are "nominal mode". Our best suggestion is to check the "NUM_SWEEPS_PER_SCAN" parameter in the SPH and see if it is equal to 17 (prior to 2005 operations).

L2 OFL Data [Prev] [Next]

[Plots of profile locations]

Recent v4.62 data for Oct 2002.
Note that "new" days are now being processed for this month, days for which the NRT data was never produced (NRT data only produced for 4 days in Oct'02)
Manuel Lopez-Puertas (IAA) has recently been sent the daily zonal mean files for that month's off-line data for his analysis of the solar storm impact.

Software Updates [Prev] [Next]

Version 5.3 of the Envisat CFI has been released (mainly useful for calculating observation geometries).

http://eop-cfi.esa.int

H2O2 (EP) [Prev] [Next]

Constructing H2O2 Seasonal Climatology from MIPAS 2003 measurements

Looking at averaging kernels reveals that the observed "peak" at around 10mb is not as distinct as first thought - very rapid loss of sensitivity at higher altitudes so that decay at high altitudes is largely determined by the a priori
Also, simulated data shows that even in the absence of any H2O2, the retrieved "null" profile shows some structure due to the parallel continuum retrieval

Pressure Retrieval (IY) [Prev] [Next]

M.Phys project attempting to retrieve tangent pressure directly from spectrum by ratio of suitably chosen microwindows.

Now including noise and variety of atmospheres/absorber uncertainties indicates RMS errors of a few % (comparable with pT retrieval) at mid altitudes but worse at higher and lower [Plot]
Next step is to compare results with pressures derived from pT retrieval
Only considering 1cm-1 microwindows for the moment, will eventually generalise to allow arbitrary widths.

TES Comparisons (CW) [Prev] [Next]

Looking at TES nadir spectra from 22 Aug 04 over the ocean

Nadir spectra are on a 0.06cm-1 grid, but grid is not aligned with starting wavenumber (923cm-1) - apparently due to TES using highly interpolated interferograms in order to register all the pixels on the same spectral grid
Visually, NESR looks to be about 100nW per pixel and apodisation with NB strong lineshape seems to give adequate agreement with simulated spectra
Next step is to attempt simple retrieval, starting with surface temperature

SF6 Retrievals (AB) [Prev] [Next]

Attempted retrieval using single, unmasked microwindow encompassing entire SF6 band to maximise S/N.

Results with simulated data show reduction in random error, as expected, especially if continuum is not retrieved simultaneously
Results with real data look unstable, though.

ASSFTS-12 Workshop [Prev] [Next]

Atmospheric Science from Space using Fourier Transform Spectrometry

Workshop to be held in Quebec, 18-20 May 2005
Reminder from Peter Bernath (U.Waterloo) for people to register
http://bernath.uwaterloo.ca/ASSFTS/

HiRDLS [Prev]

The HiRDLS instrument on the Aura satellite continues to suffer major problems thought to be due to a piece of insulation obscuring most of the field of view.

However, with much effort, Alyn Lambert (NCAR) managed to produce the first HiRDLS temperature profile last week.

Oxford MIPAS meeting#69 01 Feb 05

Oxford MIPAS meeting#69
01 Feb 05