Oxford-RAL IASI Group Meetings

Meeting#07 (07Jul15)

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

RAL: Brian Kerridge, Diane Knappett, Richard Siddans

CH4 Retrievals (DK) [Prev] [Next]

Presentation at ESA ATMOS Conference in Heraklion, June 2015

SWIR XCH4 retrieval: 3.7um gives a mixture of reflected/emitted radiation. SWIR sees to bring CH4 values down, probably due to a priori contribution. Currently working merging IASI SWIR with T+H2O retrieval code.

IASI NRT web-site (CH) [Prev] [Next]

www.nrt-atmos.cems.rl.ac.uk

Demo of IASI NRT web-site for SO2, now live. Large amount of data missing from RAL reception of Eumetsat data. Planning on adding ash as well, although still problems with numerous false detections, and NH3 and CO.

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

Writing up paper on generation of RFM LUTs for 11 molecules. Factor 22 gain in speed, about 100 for CO2 (if chi-factor and line-mixing included). Spectrally compressed to 4% of full monochromatic size. [Plot] showing effect of spectral compression using irregular grid.

Volcanic Ash (EC) [Prev] [Next]

IASI ash retrieval as part of SCOPE project. Recent meeting in Madison comparing ash retrievals from 20 or so algorithms: plume altitude, optical depth, mass, from various volcanic eruptions. Useful correlative data provided from FAAM. IASI strength seems to be in detection of ash.

Volcanic Ash (LV) [Prev] [Next]

Looking at Oxford IASI and Oxford MODIS ORAC intercomparisons for volcanic ash and found significant differences in optical depth. For IASI retrievals found unreasonably low surface temperatures, while MODIS surface temperatures often much higher than a priori. Difference in optical depth results follows from difference in surface temperature. IASI surface temperature from ECMWF profile interpolated to 0 km, but should use ECMWF surface temperature.

MetOp AVHRR (AD)

Emma Velterop (Vac student) has been working on comparisons of spectrally averaged IASI radiances (simulating AVHRR channels 4,5) with spatially averaged AVHRR radiances, using information on colocated AVHRR radiances embedded in the IASI L1C file format.

RFM (AD) [Prev] [Next]

[Report] produced on current status of infrared absorption cross-section data (in particular relation to MIPAS work).

Completed RFM calculations of monochromatic optical depth spectra for each of the 83 RTTOV profiles. Noted that HDO is significant for IASI CH4 but not separated from H2O in current UKMO list of 14 molecules.

Ongoing RFM modifications to incorporate Collision-Induced Absorption data from HITRAN.

CCI+ (BJK)

Last week Copernicus workshop on climate change service at ECMWF. Yesterday a Climate Data Steering Group meeting at RAL, planning "CCI+", follow-on from phase 2 of current ESA CCI, considering new variables, eg precursors for O3.