Oxford-RAL IASI Group Meetings

Meeting#08 (08Aug15)

Oxford: Anu Dudhia, Elisa Carboni, Lucy Ventress, Tony Vincent

RAL: Brian Kerridge, Diane Knappett, Richard Siddans

CH4 Retrievals (DK) [Prev] [Next]

Merged version of processor now on CEMS, works for a test run. Aim to get it working for NRT data - but need to read ECMWF NRT data, eg to use PV for stratospheric N2O.

SWIR retrieval development to determine residual - appears to be a difference between the 4 IASI pixels for the short-wave detectors (ghost effect).

RFM Look-Up Tables (TV) [Prev] [Next]

Passed IASI LUTs to David Moore at U.Leicester for their retrievals, but U.Leicester don't appear to be getting the expected speed advantages.

Linear Retrieval (TV) [Next]

Working on unconstrained linear retrieval, based on RTTOV ensemble of 80 atmospheric profiles. Unlike the operational Oxford SO2 NRT retrieval, this attempts to retrieve all relevant parameters together using simple noise covariance. Trying to decide which of 80 spectra is most appropriate.

Currently using 2000-2300cm-1 region, retrieving OCS, CO and 13C/12C ratio.

Monthly mean OCS shows ocean sources south of equator, also over Yemen/Oman (potentially from diesel?) - should try to correlate with SO2 products. CO shows probably biomass burning near equator and possible pollution over Beijing. Not much evident signal in 13C/12C.

Volcanic Ash (EC) [Prev] [Next]

2 volcanic eruptions in past 2 weeks, but NRT web-page stuck on 11 August.

NRT Linear Retrievals (LV) [Prev] [Next]

Aiming to expand anomaly flagging for NRT web-site to include NH3, CO and OCS.

Currently uses single global gain matrix, but want to extend this to use latitude-specific matrices.

RFM (AD) [Prev] [Next]

Extended RFM to include HITRAN Collision Induced Absorption data, although recommendation is to use O2 and N2 continua in the infrared.

Note that new Hartmann-Tran lineshape available via HITRAN ( Tran, Ngo & Hartmann (2014), doi:10.1016/j.jqsrt.2013.06.015 )

T/H2O/O3 Retrievals (RS) [Prev] [Next]

Now has a year's worth of IASI/AMSU/MHS data from EUMETSAT for investigating joint T/humidity/O3 retrievals. Joanne Walker will be working on it.