Oxford MIPAS meeting#6
21 May 02

Present

Oxford: Anu Dudhia, Jonathon Green, Oliver O'Brien, Malcolm Parks, Mark Parrington, Vivienne Payne
RAL: Victoria Jay, Brian Kerridge, Jolyon Reburn

Instrument Status [Prev] [Next]

No news - assume everything is OK

Software Updates [Next]

Software in /home/crun/eodg/mipas

Lv2PP (24th April)
ILS (25th April)

Cloud Detection [Prev] [Next]

Cloud Detection in MIPAS Spectra (PDF file - 17th April). Vac project by Dominik Kasprzyk.

MW Selection MWMAKE (AD) [Next]

Now modified to allow `remasking', ie keep same MW boundaries but change around the internal masks if requirements change

MWMAKE User's Guide

L1B Data (AD) [Next]

Orbit 504 (from 5th April) now received from ESA by ftp.

Located in /home/crun/eodg/mipas/L1B/
Quick examination shows that spectra can be read from the file
Next: try and run Lv2PP to extract apodised MW spectra

Envisat CD simulated L1B data also located in /home/crun/eodg/mipas/L1B/

RAL S/W experiences (VJ)

Lv2PP (L1B to L1C conversion - written by CP) [Prev] [Next]

Attempted to modify code to run on Envisat CD data (53-8km in 16 scans instead of 68-6km in 17 scans)
Reads limb scans 1-3 OK but fails on 4th - reason unknown.

ILS (Extract AILS lineshapes - written by CP) [Next]

Successfully run Chiara's AILS program on Envisat CD L1B data
Plot (PDF file)
Subsequent email from Herb Nett suggests we should use the `re-centred' AILS shapes, ie with spectral shift removed

Lv2 Reading s/w (written by RS from U.Le) [Prev] [Next]

Works OK, but difficult to understand structure of Lv2 data, eg assigning continuum profiles.
Extracting residuals much easier.

RAL MW selection (MPn) [Prev] [Next]

Showed plots of O3 random error reduction as a function of altitude and wavenumber for 1040-1050cm-1 region.
Improved tropospheric errors at 1042cm-1 (and worse stratosperhic errors) - 1042cm-1 corresponds to a dip in the O3 band.

CO Retrievals (OO) [Prev] [Next]

MPhys project examining the feasibility of retrieving CO from MIPAS data

Upper troposphere random error of the order of 10%, but increases rapidly with altitude
Ignoring non-LTE effects leads to errors of the order of 10% in day-time up to 12km, then much larger. Only around 2% at nighttime
Looks as if useful retrievals can be performed at night ignoring non-LTE effects, and possibly for low altitudes in the day-time.

CO2 Retrievals (JG) [Prev] [Next]

MPhys project examining the feasibility of retrieving CO2 from MIPAS data

Using 700-800cm-1 region, joint T-p-CO2 retrieval shows CO2 retrieved to precision 2-3% at low altitudes
Also investigated independent T-p retrieval using the O2 continuum feature 1500-1600cm-1 - reasonable T-p at low altitudes only
Combining O2 T-p retrieval and T-p-CO2 retrieval gives a significant improvement in the CO2 precision: <1% (presumably to helping remove the p-CO2 ambiguity using only CO2 lines for both)

Isotope Retrievals (MPs) [Prev] [Next]

MPhys project examining the feasibility of retrieving minor isotope ratios from MIPAS data

Plots showing expected precision from H2O, N2O, CO2 and CH4 isotopes (still running O3 isotopes) of the order of 10% or better
No known mechanisms for changing N2O isotope ratio in the stratosphere

RAL Plans for MIPAS data (JR) [Prev] [Next] (Presentation - PDF file)

RAL activities fall into two categories

CalVal: intercomparisons of MIPAS, SCIAMACHY, AATSR and GOME
AMIL2DA: UTLS Retrievals from MIPAS (currently takes ~30minutes/iteration for a multi-species retrieval, excl p,T).

Oxford Retrieval (VP) [Prev] [Next]

Continuing to try and modify OPTIMO to read L1C data to reproduce blind test spectra results.

Thesis overview presentation (interview practice).

Oxford MIPAS meeting#6 21 May 02

Oxford MIPAS meeting#6
21 May 02