Oxford-RAL IASI Group Meetings

Meeting#04 (17Mar15)

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RAL: Brian Kerridge, Diane Knappett, Richard Siddans

Oxford: Elisa Carboni, Anu Dudhia, Catherine Hayer, James Preston (Masters student from Earth Sciences), Lucy Ventress, Tony Vincent


EUMETSAT studies (RS) [Prev] [Next]
Completed final presentations on EUMETSAT studies, draft final reports produced. Might be an extension to link the two studies, i.e., pass the retrieval of T,H2O, Surface emissivity data into the CH4 retrieval. 3 days of test data generated (can be processed overnight using around 50 nodes). Noted that EUMETSAT have a more definitive estimate of the IASI noise characteristics than the spectrally flat models commonly used. TV: Hilton et al, BAMS, 2012 [http://dx.doi.org/10.1175/BAMS-D-11-00027.1] note that IASI noise is very stable with time.

Oxford T Retrieval (TV) [Prev]
Working on temperature retrieval from IASI CO2 bands (jointly with H2O and O3), using ECMWF pressure levels. Using RFM forward model with LUTs - processing a few hundred pixels. Investigating how to handle surface pressure, which is intermediate between ECMWF pressure levels.
AMTD paper on pressure-level selection now in discussion phase [www.atmos-meas-tech-discuss.net/8/2591/2015/amtd-8-2591-2015.html]

Ash Retrieval (LV) [Prev] [Next]
Trying to get ash retrievals ready for SCOPE intercomparisons. Now using latitude-dependent covariance matrices, and running retrievals for specific volcanic eruptions. Next task is to convert data to required format - RAL can help with this (GT probably). Tried different two different types of ash, but only a limited selection of infrared ash spectra available.

SO2 Retrievals (EC) [Prev] [Next]
Fixed a couple of problems so improved CEMS/LOTUS processing of SO2 linear retrievals - 4 years now processed. Main problem is juggling of disk space, but also some unexplained retrieval failures. Iterative retrievals running at Oxford and about to transfer these to CEMS. Writing up SO2 paper.
(JP) Looking for low-level SO2 emission signatures in time-averaged IASI SO2 linear retrievals, 2008-9. Some clear volcanic signatures, also Beijing pollution. Looked at iterative retrievals over Ecuador volcanic arc - find persitent negative SO2 signal - connected to surface elevation/emissivity?

IASI NRT web-site (CH) [Prev] [Next]
Now has a working internal version (within Oxford) but no data displayed yet. IDL bug creating netCDF4 files using 'STRING' variables - particularly a problem for DJANGO which expects date/time information as string format. Also a problem that SO2 flag seems not to be working. Aiming for public release by Easter.

CH4 Retrievals (DK) [Prev] [Next]
Modifying RAL CH4 processor to use retrieved T+H2O+Sfc emissivity. Also incorporate IASI 3.7 μm CH4 measurements.

RFM (AD) [Prev] [Next]
Part of ongoing work with UKMO, creating database of RFM high resolution optical depth spectra for ECMWF set of 83 profiles, 450-3260 cm-1 @ 0.001 cm-1 resolution. Converted to netCDF format.