Final correction algorithms for HIRDLS version 7 data

ABSTRACT The High Resolution Dynamics Limb Sounder (HIRDLS) instrument is a 21 -channel limb scanning infrared radiometer, designed to make global measurements of temperature, ozone, water vapor, eight other gases and aer osols from 8 to as KLJKDVNPZLWKNPYHUWLFDOUHVROXWLRQ'XULQJODXQFKRQ1$6$¶6$XUDVDWHOOLWHDSLHFHRILQWHULRUOLQLQJmaterial became lodged in the foreoptics, reducing the effective aperture by 80 -95 %, and inserting another signal into the system. The HIRDLS team has worked for several years to develop corrections for these effects, and recover as many as possible of the planned capabilities. This talk describes the last and probably final set of algorithms to recover the planned species. Early work developed corrections for channels with large radiances allowing temperature and ozone to be retrieved. Subsequent work has concentrated on refining these to allow species such as nitric acid, chlorofluorocarbons 11 & 12, nitrogen dioxide, N2O 5, chlorine nitrate, nitrous oxide and water vapor to be recovered. Effort has gone into studying, then parameterizing in an adaptive way, the quasi -regular way the signal from the blockage varies with time during an orbit and during the mission. Several recent improvements are described. Results of these corrections show improvements in the retrieved products. Keywords: limb scanning, limb sounding, HIRDLS, stratosphere, stratospheric temperature, ozone, nitric acid, CFC11, CFC12, nitrogen dioxide