Accession Number : ADA186126

Title :   An Analysis of Apparent-Motion Vectors in, and the Structure of, A Mid-Latitude Sporadic E Layer Using a 2.66 MHZ Radar.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s) : Halderman, Timothy D

PDF Url : ADA186126

Report Date : Jan 1987

Pagination or Media Count : 103

Abstract : We used the 2.66 MHz Imaging Middle-Atmosphere Geophysical Radar (IMAGER) located at Boot Lake, Colorado, to collect data on midlatitude sporadic E layers found near 100 km. Analysis of the data shows apparent-motion vectors, in a 20 km altitude range in and near the layers, of 200-300 m/s on one occasion and 160 m/s on another. In each case, these motions were toward the west and south. We interpret these results as phase motions of internal gravity waves, or ripples, moving through the lower thermosphere, rather than bulk wind motions. Possible lower atmosphere source regions for these internal gravity waves are identified. The sporadic E layers appeared to consist of irregularly shaped patches with scale sizes being approximately 15km. The heights of the individual patches appeared to vary as much as 3 km while the mean height of the layer varied from 106 km to as low as 96 km. We also had a 5-point tilting-filter photometer available which enabled us to calculate apparent-motions at similar altitudes. The results showed motion toward the north at approximately 100 m/s, significantly different, in both direction and speed, than the results from the radar.

Descriptors :   *E REGION, *GRAVITY WAVES, *INTERNAL WAVES, *LOW ALTITUDE, *RIPPLES, *THERMOSPHERE, *WIND, ATMOSPHERES, COLORADO, HEIGHT, LAYERS, MEAN, MOTION, RADAR, SCALE, SHAPE, SIZES(DIMENSIONS), SOURCES, TEMPERATE REGIONS, THESES, RADAR IMAGES

Subject Categories : Meteorology
      Active & Passive Radar Detection & Equipment
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE