JMA Report 24 Mar 2009 Yoshihiko Tahara Incorrect RMA equation reported in the January meeting GSICS correction for MTSAT –Don’t we need standard GSICS correction? Brief report on AIRS and IASI accuracy evaluated by the spectral compensation technique (if time is available) JMA participants in JFY2009

Which Regression? Least squares (LS) –No error in X is assumed –Y = aX + b is not equivalent to X = a’Y + b’ Major Axis regression (MA) –Unit of X and Y should be the same –Y = aX + b is equivalent to X = a’Y + b’ Reduced Major Axis reg. (RMA) –X and Y are correlated –Y = aX + b is equivalent to X = a’Y + b’ –Easy to calculate from (written in only Japanese)

MTSAT IR Data Disseminated MTSAT Packet Data raw digital counts, blackbody and space observations, sensor temperatures MTSAT HRIT Data digital counts converted on a fixed Tb grid for each IR channel, with a Tb-count table linear to rad. (no calibration coefficient contained) Calibration Interpolation in radiance space Users can retrieve Tb easily from digital count looking at the Tb-count table What is GSICS correction for MTSAT convenient for users?

Current GSICS Correction for MTSAT IR I GEO = a I LEO + b is available on the JMA/MSC Web Why producing I GEO = a I LEO + b, now? –To compute Tb biases at 290, 250 and 220 K –Easy to compare with the results of GCC Inconvenience to users –Long way to get corrected TB data – I LEO = a’ I GEO + b’ is required for the correction –Sensor Planck functions for MTSAT are also required digital count Tb radiancecorrected radiance corrected Tb Tb-count table Planck functions for MTSAT IR I LEO = a’ I GEO + b’

Choices of GSICS Correction I GEO = a I LEO + b (no change) –Complicate to get corrected Tb count  Tb  rad.  corrected rad.  corrected Tb We got complaint from some researchers before. I LEO = a N GEO + b (corrected calibration equation) –Equation to get corrected radiance from digital count N GEO –Simpler digital count  corrected rad.  corrected TB Corrected TB-count table –The simplest digital count  corrected TB –Increase the volume Something else?

Define Standard GSICS Correction? To avoid confusion for users Standard expression? –I LEO = a N GEO + b (corrected calibration equation) All GPRCs may be applicable RMA regression keeps consistency with I GEO = a I LEO + b Standard LEO data usage? –Combine all LEOs (AIRS & IASI), Separate AIRS & IASI –Separate day & night, Separate LEO orbits Standard frequency to update the equation? –Every day, every week, every month, etc Standard period of data used to generate the equation? –One month, latest 30 days, latest 7 days, etc. Allow options for GPRCs –e.g.) Separate LEO orbits to correct MTSAT diurnal variation

larger AIRS noise AIRS erroneous channel (#276) Error trend in an AIRS detector module Normalized Standard Deviation Diff. (SD/Rad) between Observed and Estimated Radiances red: AIRS black: IASI larger IASI noise larger AIRS noise Blacklisted AIRS channels excluded

consistent red and black indicates biases associated with the spectral compensation method Mean TB Difference between Observation and Estimation red: AIRS black: IASI Blacklisted AIRS channels excluded large biases for AIRS #121 and #122 small biases for AIRS #133 and #134

JMA Participants in JFY2009 GSICS EP –Mr Toshiyuki Kurino (transition is planed) GRWG and GDWG –Ms Hiromi Owada for IR calibration (in GDWG & GRWG) –Mr Arata Okuyama for VIS calibration (in GRWG) –Mr Kenji Date (in GRWG) –Mr Ryuichiro Nakayama (in GDWG) Contact person for operation & product acceptance –Ms Hiromi Owada Leaving GSICS –Mr Yoshihiko Tahara –Mr Koji Kato Please update your address books!