HR: 13:50h
AN: A12C-01 INVITED     [PDF]
TI: The High Resolution Dynamics Limb Sounder (HIRDLS) Experiment on Aura
AU: * Gille, J C
EM: gille@ucar.edu
AF: U. of Colorado and NCAR, PO Box 3000, Boulder, CO 80307 United States
AU: Barnett, J J
EM: j.barnett1@physics.ox.ac.uk
AF: Oxford University Department of Physics, Clarendon Laboratory, Oxford, OX1 3PU United Kingdom
AB: Previous space-based observations have contributed much to our knowledge of the stratosphere in recent decades. These observations have been characterized by large horizontal or vertical scales, leaving a range of unobserved phenomena at smaller scales. This is especially true near the tropopause, where rapid vertical changes in temperature and composition have been unobserved on a global basis. This presentation will briefly review some of the current science questions, including troposphere-stratosphere exchange, both in the tropics and mid-latitudes, as well as filamentation at internal barriers in the atmosphere, and the requirements they place on the desired measurements. Accurate and precise observations of temperature, and a number of trace species having a range of atmospheric lifetimes as well as different source and sink regions are needed, with horizontal resolutions of a few degrees or less, and vertical resolutions of $\sim$ 1 km. The species chosen are O3, H2O, CH4, N2O, NO2, N2O5, HNO3, CFC11, CFC12, ClONO2, and aerosol properties. New requirements on the instrument include the ability to make measurements at multiple azimuths, using narrow fields of view, oversampling, multiple spectral intervals for some species, as well as high radiometric accuracy and precision, and careful calibration. The instrument description shows how these requirements are met. The HIRDLS instrument is a 21 channel limb-scanning infrared radiometer, based on a folded off-axis telescope and HgCdTe detectors cooled to 62 K. The 2-axis scan mirror is capable of making vertical scans across the limb over a wide range of azimuths from the orbital plane, resulting in complete global coverage of all species. The scan parameters are programmable from the ground, so observations may be tailored to specific geophysical situations. Finally, examples of retrievals of simulated radiances illustrate the expected precision and resolution of the data.
UR: http://www.eos.ucar.edu/hirdls/
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0340 Middle atmosphere--composition and chemistry
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 0394 Instruments and techniques
DE: 3334 Middle atmosphere dynamics (0341, 0342)
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting