Data Set Overview
    =================
      The Ames Mars General Circulation Model is a three dimensional
      model based on the primitive equations of meteorology.  It
      includes the radiative effects of dust and carbon dioxide as
      well as other features such as large-scale topography (see
      [POLLACKETAL1990]; [BARNESETAL1993]; and [HABERLEETAL1993]).
 
      The model has 25 latitude bins (7.5 degree resolution), 40
      longitude bins (9.0 degree resolution) and 13 vertical layers.
      The spacing between each layer varies.  The following array
      defines the layer spacing from the tropopause to the surface in
      mbars:
 
        0.005779, 0.009511, 0.01568, 0.02585, 0.04263, 0.07025,
        0.1159, 0.1544, 0.1586, 0.1364, 0.1223, 0.09270, 0.05000.
 
      The model spins up from a resting isothermal state with the
      global temperature equal to 200K.  The spin up starts with hour
      equal to 0.  The model saves data every 1.5 hours for a total
      of 16 hour bins per day.
 
      Some other initial conditions that are set when the model spins
      up:
 
      INITIAL SURFACE PRESSURE      : 7.60 mbars
      TROPOPAUSE PRESSURE           : 0.06699 mbars
      DUST OPTICAL DEPTH            : 0.3 (for periods where Ls < 200)
      DUST OPTICAL DEPTH            : 1.0 (for periods where Ls > 200)
      ICE CLOUD OPTICAL DEPTH       : 0.00
      TIME STEP                     : 9.25 minutes
      RICHARDSON NUMBER TIME SCALE  : 200000000. seconds
      SCALE HEIGHT FOR DUST PROFILE : 0.03000
      TIME CONSTANT FOR RAYLEIGH
        FRICTION                    : 2.0000 days
 
      This data set is composed of 20 to 30 day averages of the data
      resulting from model runs simulating martian conditions for
      four Ls periods during 1977 (Ls 10-24, 94-103, 202-220, and
      267-286).
 
        Native start time  =  10.15 AREOCENTRIC LON, EARTH YEAR 1977
        Native stop time   = 286.09 AREOCENTRIC LON, EARTH YEAR 1977
 
      The lat-time data set contains the zonally averaged values for
      the surface temperature mean.  The data are given as a function
      of latitude and local time.  The calculations are done in the
      pi coordinate system; pi coordinates are located at the
      intersection points of a set of evenly spaced latitude circles
      and a set of evenly spaced longitude circles.
 
      The data set is in the following configuration (listed as field
      followed by description):
 
      LATITUDE
        Latitude, degrees
 
      TIME
        Local time, hr
 
      SURF_TEMP_MEAN
        Mean surface temperature, K

Confidence Level Overview
    =========================
      The Ames Mars General Circulation Model is a three dimensional
      computer model based upon the primitive equations of
      meteorology.  It includes the radiative effects of dust and
      carbon dioxide as well as other features such as large-scale
      topography.  Model results are dependent upon the selected
      initial conditions and spatial and temporal resolution of the
      model, and may not fully incorporate the effects of some
      physical processes represented by paramaterizations made by the
      model.