Accession Number : AD0726994

Title :   Synoptic and Climatological Density Profiles from Constant Pressure Surfaces for Ballistic Computations.

Descriptive Note : Air Force surveys in geophysics,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Sissenwine,Norman ; Cole,Allen E. ; Salmela,Henry A. ; Kantor,Arthur J.

Report Date : 04 MAR 1971

Pagination or Media Count : 39

Abstract : The influence of atmospheric density on ballistic trajectories of re-entry vehicles usually attains a maximum below 20 kilometers. The most direct and accurate means of estimating this influence is from profiles of density specified at uniform intervals of altitude (usually 2 km) from individual soundings for the time and over the area of re-entry. Unfortunately, vertical distances between levels on constant pressure charts, normally available for obtaining density profiles, are generally greater than 2 kilometers. Unless interpolation between these pressure surfaces for obtaining densities at the 2-km intervals is based on the actual density-altitude relation, the interpolated densities will be in error. Three often-used methods of interpolation are: (1) assumption of a linear decrease of density with altitude, (2) assumption of a linear decrease of the logarithm of density with altitude, and (3) assumption of a linear decrease of density multipliers with altitude, where a density multiplier at the altitude of a constant pressure surface represents the ratio of density to the Standard Atmosphere density at that altitude. The three methods with resultant errors are discussed and evaluated in this report. (Author)

Descriptors :   (*UPPER ATMOSPHERE, DENSITY), (*ATMOSPHERE ENTRY, *DESCENT TRAJECTORIES), BAROMETRIC PRESSURE, INTERPOLATION, ERRORS, TABLES(DATA), REENTRY VEHICLES

Subject Categories : Atmospheric Physics
      Armor

Distribution Statement : APPROVED FOR PUBLIC RELEASE