anu dudhia university of oxford - earth online - esa€¦ · oxford processor: c2h2, clo, h2o2,...
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Oxford Activities
Anu DudhiaUniversity of Oxford
MIPAS QWG#40IFAC 2-4 Nov 2015
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New Species
• Microwindows selected but not yet tested with Oxford processor: C2H2, ClO, H2O2, HCOOH, CFC-113, CFC-114, COCl2, CH3Cl, plus isotopologues HDO, CH3D, and 4 ozone variants.
• Note that LUTs for minor isotopologues will have to treat these as new molecules, with main isotopologues treated as contaminants.
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Look-Up Tables
• Major revision of code used to generate LUTs, incorporating new RFM, new MIPAS spectroscopic data
• New selection of heavy molecule cross-section data (see Tech Note from last QWG)
• Smoothing algorithm developed to reduce noise in cross-section data (pseudo-Kalman smoother)
• Work currently paused pending non-LTE investigations ...
Impact of new non-LTE calculations on current retrievals
Anu DudhiaUniversity of Oxford
MIPAS QWG#40IFAC 2-4 Nov 2015
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Non-LTE Calculations
• Non-LTE effects are modelled using vibrational temperatures supplied by IAA. These mostly affect day-time, high altitude and short wavelengths.
• Microwindow selection and error analysis allows for a single 'non-LTE' error representing the difference between non-LTE and LTE calculations.
• Original non-LTE error spectra were pre-launch, updated spectra were calculated in 2012 and a new set has recently been calculated.
• Question: do the new non-LTE calculations justify reselecting microwindows?
• The following plots show error-budget calculations for the major species with all three versions of non-LTE error spectra
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Temperature Errors
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H2O Errors
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O3 Errors
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HNO3 Errors
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CH4 Errors
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Conclusions
• For most species, new non-LTE spectra have little impact
• For CH4, N2O non-LTE error has decreased significantly (tbc)?
• For NO2, OR, error has increased at high altitude, but still less than random error
• Summary: no need to reselect microwindows