Accession Number:

ADA048851

Title:

The Semiannual Variation in the Upper Atmosphere (900-1200 km) at Solar Minimum.

Descriptive Note:

Technical memo. 1974-1976,

Corporate Author:

JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB

Personal Author(s):

• Eisner,A.
• Yionoulis,S. M.

Report Date:

1977-09-01

Pagination or Media Count:

37.0

Abstract:

A new method has been developed that uses satellite along-track position errors to obtain information on atmospheric densities at altitudes of 900 to 1200 km. The data based used was the daily tracking results from the Navy Navigation Satellite System NNSS. Densities derived from these data for the years 1974-76 show a pronounced semiannual variation, with the AprilOctober maxima exceeding the AugustJanuary minima by factors of 2 to 4. The variation is more pronounced than was previously reported, and double the best current modeled variation. The current resolution with this technique is estimated to be 1 x 10 to the -19th power gmcu cm, or about 10 of the total density at these altitudes. Author

Descriptors:

• *ATMOSPHERIC DENSITY
• SEASONAL VARIATIONS
• ERROR ANALYSIS
• RESONANCE
• NAVIGATION SATELLITES
• SOLAR ACTIVITY
• POLAR ORBIT TRAJECTORIES
• ATMOSPHERE MODELS
• UPPER ATMOSPHERE
• GEOPOTENTIAL
• SATELLITE TRACKING SYSTEMS

Subject Categories:

• Atmospheric Physics
• Geodesy
• Spacecraft Trajectories and Reentry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE