The High Resolution Doppler Imager (HRDI) Level 3AT data product consists of daily, 65.536 second interval time-ordered vertical profiles of meridional and zonal wind components, temperature and volume emmission rate of O2.  The instrument measured Doppler shifts of spectral lines in the visible and near-IR between 400 and 800 nm.  HRDI was flown on NASA's Upper Atmosphere Research Satellite (UARS) and designed to measure winds and other parameters in the mesosphere and lower thermosphere by primarily observing the Doppler shift of emitted light, and in the stratosphere by observing the Doppler shift of atmospheric absorption features. Measurements were made in the mesosphere between 50 and 115 km, and in the stratosphere between 10 and 40 km at about 2.5 km resolution. Data were collected between latitude 40S and 76N and 76S and 40N, alternating each satellite yaw cycle of about 36 days. The HRDI Level 3AT data were processed with the version 11 algorithm.

The HRDI level 3AT product consists of 8 granules per day. A data granule is one HRDI species or subtype per day.  The following subtypes are available:

 1) MERWIN_A - meridional wind component on altitude grid  [m/s]
 2) MERWIN_P - meridional wind component on pressure grid  [m/s]
 3) ZONWIN_A - zonal wind component on altitude grid       [m/s]
 4) ZONWIN_P - zonal wind component on pressure grid       [m/s]
 5) TEMP_A - temperature on altitude grid                  [Kelvin]
 6) TEMP_P - temperature on pressure grid                  [Kelvin]
 7) VOLER_A - O2 volume emission rate on altitude grid     [cm-3]
 8) VOLER_P - O2 volume emission rate on pressre grid      [cm-3]

HRDI data are on the UARS standard altitude levels (in km) given by:

z(i) = 5*i                 for i<=12
z(i) = 60 + (i-12)*3       for 13 <= i <= 32
z(i) = 120 + (i-32)*5      for 33 <= i <= 88

as well as the UARS standard pressure levels (in mbars) given by:

P(i) =  1000 * 10**(-i/6)  for i = 0, 1, 2, ...

The data files are available in a binary record oriented format.