Data Set Overview : All ALTITUDE data are packaged by periapsis number for each aerobraking orbit. ALTITUDE data are provided in a table labeled Pyyy.tab where 'yyy' is the three digit periapsis number.  Parameters : Altitude: Units : km Latitude: Units : degrees Longitude: Units : degrees Local Solar Time: Units : N/A Longitude of the Sun: Units : degrees Solar Zenith Angle: Units : degrees Density: Units : kg/km**3 Sigma Density: Units : kg/km**3 Scale Height: Units : km Sigma Scale Height: Units : km  Data : For each orbit, ALTITUDE data consist of an 15 by 10 array in the file folder Pyyy. Each row gives atmospheric characteristics at a constant altitude. When applicable, inbound and outbound legs are in separate rows. The altitude levels going from row 1 to row 11 are: periapsis, 1.26 nbar inbound, 1.26 nbar outbound, 100 km inbound, 100 km outbound, 110 km inbound, 110 km outbound, and so on to 150 km inbound, 150 km outbound. The columns from one to ten are separated as follows: altitude, latitude, longitude, local solar time, longitude of the sun, solar zenith angle, density, sigma density, scale height, and sigma scale height.  Processing : Density and density scale heights are provided at reference altitudes of periapsis, 1.26 nbar, 100, 110, 120, 130, 140 and 150 km. Except for periapsis, these are obtained by a least squares fit to the 39 point running mean data sets that span 5 km on either side of a reference altitude for both the inbound and outbound portions of the orbit. The values at periapsis are obtained by a similar fit to all data within 10km of the periapsis altitude. See [TOLSONETAL2007].  Coordinate System : Latitude and longitude are in the IAU Mars Centered Mars Equatorial System. Altitude is above the IAU reference ellipsoid with a:3396.19 km and f:0.005886.

Confidence Level Overview : Standard deviations on density and scale height are based on the formal covariance matrix for the linear regression of log density and altitude. Data noise is assumed to be the standard deviation of the fit.  Review : Comparisons were made with operational data sets. Deviations were within expectations.  Data Coverage and Quality : Data coverage during an aerobraking pass varied throughout the mission. The nominal pass assured that sufficient data were recovered above 250 km to calibrate the accelerometers both inbound and outbound.