The Halogen Occultation Experiment (HALOE) on NASA's Upper Atmosphere Research Satellite (UARS) investigates upper atmosphere chemistry, dynamics and radiative processes, particlarly stratospheric ozone ... destruction and chlorofluromethane impact on ozone.
HALOE is a solar occultation experiment designed to monitor the vertical distribution of HCl, HF, CH4, and NO by gas filter correlation radiometry and H2O, NO2, O3, and CO2 by broadband filter radiometry. The HALOE instrument typically views 15 sunrise and sunset events each day, scanning the solar disk from limb to limb during each event. The latitude/longitude location of the HALOE data varies with the spacecraft-Earth-Sun position. For a given day, the locations tend to be in two distinct latitude bands and to sweep across the full longitude range. Coverage across the full range of latitudes is achieved on a time period ranging from about two to six weeks depending on the time of year. The latitude coverage extends from 80 degrees north to 80 degrees south.
The HALOE level 3AT data consist of 13 granules per day. A data granule is one HALOE species or subtype per day. The following subtypes are available: 1) AEXTCH4 - aerosol extinction at 3.46 um (CH4 gas filter), 2) AEXTCO2 - aerosol extinction at 2.80 um (CO2 gas filter), 3) AEXTHCL - aerosol extinction at 3.40 um (HCL gas filter), 4) AEXTHF - aerosol extinction at 2.45 um (HF gas filter), 5) AEXTNO - aerosol extinction at 5.26 um (NO gas filter), 6) CH4 - methane, 7) H2O - water vapor, 8) HCL - hydrogen chloride, 9) HF - hydrogen fluoride, 10) NO - nitric oxide, 11) NO2 - nitrogen dioxide, 12) O3 - ozone, and 13) TEMP - atmospheric temperature. Aerosol extinction coefficients are measured in units of 1/km, chemical species are given in parts per million by volume (ppmv), and temperature is in units of degrees Kelvin.
Each of the 13 HALOE granules is accompanied by 2 additional parameter files, designated as level 3TP. The first parameter file, subtype LAT, contains the latitude values for each pressure level of each event for the day. The second parameter file, subtype LON, contains the longitude values. The level 3AT files only contain the latitude/longitude location corresponding to the 30 km retrieval point.
The HALOE level 3AT data product consist of profiles that have been interpolated both vertically and horizontally from the original profiles to standard surfaces and locations defined by the UARS project for all limb-viewing instruments. The level 3AT format is common to all UARS instruments to allow for intercomparison. The level 3AT data product consists of time-ordered profiles, and are spaced at intervals of 1 UARS minute (65.536 seconds), or about 495 km along the tangent track (horizontal resolution). The vertical resolution for the level 3AT HALOE profiles is defined by the UARS pressure levels (in mbars) given by:
P(i) = 1000 * 10**(-i/6) for i = 0, 1, 2, ...
which gives approximately 2.5 km increments between pressure surfaces.
Hervig, M. E., J. M. Russell III, L. L. Gordley, J. H. Park, and S. R. Drayson, Observations of Aerosol by the HALOE Experiment Onboard UARS: A Preliminary Validation, Geophys. Res. Lett., 20, No 12, ... 1291-1294, June 18, 1993
Luo, M., J. M. Russell III, R. I. Cicerone, and L. L. Gordley, Analysis of Selected Nitric Oxide Observations in the Lower Thermosphere by HALOE on UARS , Geophys. Res. Lett., 20, No. 12, 1307-1310, June 18, 1993
Mote, T. L., J. R. Holton, J. M. Russell III, and B. A. Boville, A Comparison of Observed (HALOE) and Modeled (CCM2) Methane and Stratospheric Water Vapor, Geophys. Res. Lett., 20, No. 14, 1419-1422, July 23, 1993
Pierce, R. B., W. L. Grose, J. M. Russell III, and A. F. Tuck, 1994: Evolution of Southern Hemisphere Spring Air Masses Observed by HALOE, Geophys. Res. Lett., February 1, 1994
Tuck, A. F., J. M. Russell III, and J. E. Harries, Stratospheric Dryness: Antiphased Desiccation Between Micronesia and Antarctica, Geophys. Res. Lett., 20, No 12, 1227-1230, June 18, 1993
Tuck, A. F., J. M. Russell III, S. J. Hovde, K. K. Kelly, C. R. Webster, and R. D. May, Intercomparison of HALOE and ER-2 Aircraft Data Collected During the Second Airborne Arctic Stratospheric Experiment AASE-II), Geophys. Res. Lett., 20, No. 12, 1243-1246, June 18, 1993
Reber, C. A., C. E. Trevathan, R. J. McNeal, and M. R. Luther, The Upper Atmosphere Research Satellite (UARS) Mission, J. Geophys. Res., 98, No. D6, 10,643-10,647, June 20, 1993
Russell, J. M. III, L. L. Gordley, J. H. Park, S. R. Drayson, D. H. Hesketh, R. I. Cicerone, A. F. Tuck, J. E. Frederick, J. E. Harries, and P. J. Crutzen, The Halogen Occultation Experiment, J. Geophys. Res., 98, No. D6, 10,777-10,797, June 20, 1993
Russell, J. M. III, A. F. Tuck, L. L. Gordley, J. H. Park, S. R. Drayson, J. E. Harries, R. I. Cicerone, and P. J. Crutzen, HALOE Antarctic Observations in the Spring of 1991, Geophys. Res. Lett., 20, No. 8, 719-722, April, 23, 1993
