Interpretation of tilt measurements in the period range above that of the tides /

Translated from the German by K. Bennett Howe, International Translation Company.ADA074525 (from http://www.dtic.mil)."Terestrial Sciences Division Project 7600.""25 April 1979."Includes bibliographical references (pages 85-88).Mode of access: Internet

Magnetic disturbance statistics from a single station Q index applied to an actual OTH-B radar situation /

Due to the systematic diurnal motion of the auroral oval, the Q values of magnetic activity derived from a single station are not directly usable to determine the expected degree of auroral activity. To remove the diurnal effects from a single station data base, which leads in daytime to an under-estimation of the Q index, an empirical set of detrending factors was determined for the Sodankyla Q data base. These factors show that the probability that a given level of magnetic activity will be exceeded for a given duration is underestimated by up to a factor of 2 in the least sensitive daytime sector. The detrended data base has been analyzed to determine the probability that a given Q value is exceeded for a selected duration. This analysis has been done for durations up to 12 hr separately for the night and daytime detrended data bases. The results are very similar and confirm that the detrending has been successfully accomplished. Finally the individual and cumulative probabilities that a given Q is exceeded for a selected duration (periods from 0.25 to 24 hr) have been established for the fully detrended data base. To interpret the results in their effect on the Over-the-Horizon Experimental Radar System, the distribution of probabilities has been modulated with the dynamics of the auroral oval by use of the Starkov equation (1969). This permits the assessments of the probability that a fixed location in the radar coverage area is under the auroral oval.Research supported by the Air Force Geophysics Laboratory, Air Force Systems Command, United States Air Force, Hanscom AFB, Massachusetts.Space Physics Division Project 4643.ADA084808 (from http://www.dtic.mil)."18 December 1979."Includes bibliographical references.Due to the systematic diurnal motion of the auroral oval, the Q values of magnetic activity derived from a single station are not directly usable to determine the expected degree of auroral activity. To remove the diurnal effects from a single station data base, which leads in daytime to an under-estimation of the Q index, an empirical set of detrending factors was determined for the Sodankyla Q data base. These factors show that the probability that a given level of magnetic activity will be exceeded for a given duration is underestimated by up to a factor of 2 in the least sensitive daytime sector. The detrended data base has been analyzed to determine the probability that a given Q value is exceeded for a selected duration. This analysis has been done for durations up to 12 hr separately for the night and daytime detrended data bases. The results are very similar and confirm that the detrending has been successfully accomplished. Finally the individual and cumulative probabilities that a given Q is exceeded for a selected duration (periods from 0.25 to 24 hr) have been established for the fully detrended data base. To interpret the results in their effect on the Over-the-Horizon Experimental Radar System, the distribution of probabilities has been modulated with the dynamics of the auroral oval by use of the Starkov equation (1969). This permits the assessments of the probability that a fixed location in the radar coverage area is under the auroral oval.Mode of access: Internet

Hydrometeor data and analytical-theoretical investigations pertaining to the SAMS rain erosion program of the 1972-73 season at Wallops Island, Virginia : AFGL/SAMS Report No. 5 /

Radar, aircraft, and surface measurement information is presented concerning the liquid-water-content values and size distribution properties of the hydrometeors that existed along the trajectory paths of the four SAMS missiles that were fired into Wallops storm during the 1972-73 season."Meteorology Division Project 627A.""ADA051192 (from http://www.dtic.mil).""5 July 1977."Includes bibliographical references.Radar, aircraft, and surface measurement information is presented concerning the liquid-water-content values and size distribution properties of the hydrometeors that existed along the trajectory paths of the four SAMS missiles that were fired into Wallops storm during the 1972-73 season.Mode of access: Internet

Seismo-acoustic effects of sonic booms on archeological sites, Valentine Military Operations Area /

Seismo-acoustic recordings of sonic booms were made at two sites in the Valentine Military Operations Aras (MOA). Each location was selected as representative of a class of significant archeological sites found within the MOA. These studies indicate that sonic booms are unlikely to cause damage to the archeological finds. The expected motions are, at worst, 8 percent of the limits set by strict blasting codes and comparable to velocities that could be produced by local earthquakes which have occurred in the Valentine area. At these levels of motion, competent rock will be unaffected by the transmission of seismic waves. The predicted velocity levels are unlikely to initiate either fracture or spalling in rocks. However, it is possible that in rocks where natural meteorological action has initiated these erosive mechanisms the sonic boom induced motion accelerate the processes to some small, and probably insignificant, degree.Research supported by the Air Force Geophysics Laboratory, Air Force Systems Command, United States Air Force, Hanscom AFB, Massachusetts.Terrestrial Sciences Division Project 7600.ADA139581 (from http://www.dtic.mil)."9 November 1983."Includes bibliographical references (pages 35-36).Seismo-acoustic recordings of sonic booms were made at two sites in the Valentine Military Operations Aras (MOA). Each location was selected as representative of a class of significant archeological sites found within the MOA. These studies indicate that sonic booms are unlikely to cause damage to the archeological finds. The expected motions are, at worst, 8 percent of the limits set by strict blasting codes and comparable to velocities that could be produced by local earthquakes which have occurred in the Valentine area. At these levels of motion, competent rock will be unaffected by the transmission of seismic waves. The predicted velocity levels are unlikely to initiate either fracture or spalling in rocks. However, it is possible that in rocks where natural meteorological action has initiated these erosive mechanisms the sonic boom induced motion accelerate the processes to some small, and probably insignificant, degree.Mode of access: Internet

Variability of atmospheric density in the middle atmosphere /

An analysis of the time and space variability of density in the middle atmosphere has been developed in this report, affording a means to determine density changes that occur over distances out to 200 nmi and time periods of 1 to 72 hr. Spatial variations - The rms differences between densities at locations 50, 100, and 200 nmi apart are provided in Tables 4, 8 and 11 for low- and middle- latitude stations at altitudes from 20 through 60 km. These rms values are estimates of the day-to-day variability around the mean density gradients given in Table 5 for low latitudes and Tables 9 and 12 for middle latitudes. Time variations - The rms variability of density for time periods from 1 to 12 hr in tropical regions is given in Table 13 for altitudes up to 60 km. Estimates were derived using autocorrelation theory and an analysis of the diurnal variation of density, which is the dominant periodic cycle at low latitudes. Analyses of available density observations at several midlatitude locations for altitudes between 30 and 60 km provide reasonable estimates of the magnitude (and changes with season and latitude) of the variability of density with time for periods up to 72 hr. Variations of density at these latitudes are relatively small during summer and do not increase significantly with time. Rms variations remain between 1-1/2 and 4 percent for all periods up to 72 hr.Research supported by the Air Force Geophysics Laboratory, Air Force Systems Command, United States Air Force, Hanscom AFB, Massachusetts.Meteorology Division Project 6670."17 March 1983."Includes bibliographical references (page 24).An analysis of the time and space variability of density in the middle atmosphere has been developed in this report, affording a means to determine density changes that occur over distances out to 200 nmi and time periods of 1 to 72 hr. Spatial variations - The rms differences between densities at locations 50, 100, and 200 nmi apart are provided in Tables 4, 8 and 11 for low- and middle- latitude stations at altitudes from 20 through 60 km. These rms values are estimates of the day-to-day variability around the mean density gradients given in Table 5 for low latitudes and Tables 9 and 12 for middle latitudes. Time variations - The rms variability of density for time periods from 1 to 12 hr in tropical regions is given in Table 13 for altitudes up to 60 km. Estimates were derived using autocorrelation theory and an analysis of the diurnal variation of density, which is the dominant periodic cycle at low latitudes. Analyses of available density observations at several midlatitude locations for altitudes between 30 and 60 km provide reasonable estimates of the magnitude (and changes with season and latitude) of the variability of density with time for periods up to 72 hr. Variations of density at these latitudes are relatively small during summer and do not increase significantly with time. Rms variations remain between 1-1/2 and 4 percent for all periods up to 72 hr.Mode of access: Internet

A modern thermo-kinetic warm fog dispersal system /

An extensive investigation has been made to arrive at optimum specifications for a thermo-kinetic warm fog dispersal system. This study included passive heat tests, sub-scale heat/momentum tests, and tests with a single full-scale runway combustor and an approach zone combustor. These tests were augmented with extensive analytical modeling of buoyant jets under coflowing and counterflowing wind conditions. The landing category and the operational requirements within each category are the primary factors affecting the size of the thermal fog dispersal system (TFDS). A Cat 2 TFDS employs 22 percent fewer combustors and uses 50 percent less fuel than a Cat 1 TFDS. The combustor specification and orientation are presented for both Cat 1 and Cat 2 systems. (Author).Research supported by the Air Force Geophysics Laboratory, Air Force Systems Command, United States Air Force, Hanscom AFB, Massachusetts.Meteorology Division Project 2093."14 November 1978."Includes bibliographical references (pages 27-28).An extensive investigation has been made to arrive at optimum specifications for a thermo-kinetic warm fog dispersal system. This study included passive heat tests, sub-scale heat/momentum tests, and tests with a single full-scale runway combustor and an approach zone combustor. These tests were augmented with extensive analytical modeling of buoyant jets under coflowing and counterflowing wind conditions. The landing category and the operational requirements within each category are the primary factors affecting the size of the thermal fog dispersal system (TFDS). A Cat 2 TFDS employs 22 percent fewer combustors and uses 50 percent less fuel than a Cat 1 TFDS. The combustor specification and orientation are presented for both Cat 1 and Cat 2 systems. (Author).Mode of access: Internet

Daily magnetograms for 1982 from the AFGL network /

Research supported by the Air Force Geophysics Laboratory, United States Air Force, Hanscom AFB, Massachusetts.Space Physics Division Project 7601."1 March 1985."Mode of access: Internet

Considerations relative to adapting TRANSIT observations to predicting radar range correction /

Uncertainties in the output data of SPACE TRACK radars caused by the variability of the ionosphere may be reduced 25 to 50 percent through the use of predictions of monthly median effects supplied by AWS/GWC. For some ADCOM missions this degree of correction is inadequate and a further reduction in error is necessary. This may be gained by using local measurements of ionospheric parameters, such as total electron content which may be obtained from TRANSIT satellite passes, to adapt the model ionosphere. An algorithm is proposed which uses data from sequential TRANSIT passes over a limited portion of the field of view of each ADCOM radar, to adapt the AWS/GWC prediction for the entire field of view. From the available TRANSIT data, it is estimated that the rms refraction error may be reduced by a factor of 3 to 4 by this technique. The principle problem which must be addressed by an adaptive technique is the inherent temporal and spatial variability of the ionosphere. The expected day-to-day variability is about 20 to 25 percent of the monthly median over a solar cycle for stations from the equator to auroral latitudes. In using TRANSIT data to adapt a local estimate of the ionospheric refraction correction, it is suggested that: 1. The adaptive techniques proposed, using TRANSIT data, should be tested against archive data. 2. Techniques using other sensors of the ionosphere, such as measurements of total electron content to synchronous satellites, should be developed and tested against archive data, and the results should be compared with the technique using TRANSIT data before a final method of correction is adapted. (Author)."Space Physics Division Project ADXP."ADA038238 (from http://www.dtic.mil)."12 January 1977."Includes bibliographical references (pages 41-42).Uncertainties in the output data of SPACE TRACK radars caused by the variability of the ionosphere may be reduced 25 to 50 percent through the use of predictions of monthly median effects supplied by AWS/GWC. For some ADCOM missions this degree of correction is inadequate and a further reduction in error is necessary. This may be gained by using local measurements of ionospheric parameters, such as total electron content which may be obtained from TRANSIT satellite passes, to adapt the model ionosphere. An algorithm is proposed which uses data from sequential TRANSIT passes over a limited portion of the field of view of each ADCOM radar, to adapt the AWS/GWC prediction for the entire field of view. From the available TRANSIT data, it is estimated that the rms refraction error may be reduced by a factor of 3 to 4 by this technique. The principle problem which must be addressed by an adaptive technique is the inherent temporal and spatial variability of the ionosphere. The expected day-to-day variability is about 20 to 25 percent of the monthly median over a solar cycle for stations from the equator to auroral latitudes. In using TRANSIT data to adapt a local estimate of the ionospheric refraction correction, it is suggested that: 1. The adaptive techniques proposed, using TRANSIT data, should be tested against archive data. 2. Techniques using other sensors of the ionosphere, such as measurements of total electron content to synchronous satellites, should be developed and tested against archive data, and the results should be compared with the technique using TRANSIT data before a final method of correction is adapted. (Author).Mode of access: Internet

The diurnal variation of turbopause height /

Utilizing chemical release observations, and recently reported turbopause heights based upon mass spectrometer measurements of the Ar/N2 ratio, the diurnal variability of turbopause height is determined. Separation of the data, on a seasonal basis, shows that there is a strong winter diurnal variability with turbulence carrying to its highest altitude (approximately 115 km) between sunset and midnight, and minimizing at the noon hour. The spring data shows a similar variability, but at an overall lower altitude than that of winter, and a possible latitudinal difference, while the fall results demonstrate no real diurnal variation, and an average turbopause height at approximately 106 km.Research supported by the Air Force Geophysics Laboratory, Air Force Systems Command, United States Air Force, Hanscom AFB, Massachusetts.Aeronomy Division Project 6690.ADA099340 (from http://www.dtic.mil)."3 November 1980."Includes bibliographical references (page 11).Utilizing chemical release observations, and recently reported turbopause heights based upon mass spectrometer measurements of the Ar/N2 ratio, the diurnal variability of turbopause height is determined. Separation of the data, on a seasonal basis, shows that there is a strong winter diurnal variability with turbulence carrying to its highest altitude (approximately 115 km) between sunset and midnight, and minimizing at the noon hour. The spring data shows a similar variability, but at an overall lower altitude than that of winter, and a possible latitudinal difference, while the fall results demonstrate no real diurnal variation, and an average turbopause height at approximately 106 km.Mode of access: Internet

SCATHA satellite instrumentation report : thermal plasma analyzer : rapid scan particle detector : electron beam system : positive ion beam system /

The Air Force Geophysics Laboratory will furnish four experiments for the synchronous research satellite SCATHA (Spacecraft Charging at High Altitudes) scheduled for launch in 1978. These instruments include: (1) Boom and surface mounted gridded probes to measure the thermal (0 to 100 eV) plasma environment and the structure of the satellite photo-sheath; (2) A combination of electrostatic analyzers and solid state spectrometers to measure the plasma particle fluxes (50 eV to 10 MeV) responsible for the spacecraft charging phenomena and transient charging effects; (3) An electron beam system able to eject electrons with from 50 eV to 3 keV in energy to attempt to correct for charging caused by environmental electrons; (4) An ion beam system able to eject ionized xenon with 1 keV and 2.5 keV energies, to attempt to duplicate charging caused by environmental electrons. These instruments will be part of the total SCATHA instrumentation which consists of engineering and environmental definition experiments. Acting in concert, these instruments will test charge neutralizing procedures and provide data to specify design criteria for future synchronous satellites.Research supported by the Air Force Geophysics Laboratory, Air Force Systems Command, United States Air Force, Hanscom AFB, Massachusetts.Space Physics Division Project ILIR.ADA035506 (from http://www.dtic.mil)."10 September 1976."The Air Force Geophysics Laboratory will furnish four experiments for the synchronous research satellite SCATHA (Spacecraft Charging at High Altitudes) scheduled for launch in 1978. These instruments include: (1) Boom and surface mounted gridded probes to measure the thermal (0 to 100 eV) plasma environment and the structure of the satellite photo-sheath; (2) A combination of electrostatic analyzers and solid state spectrometers to measure the plasma particle fluxes (50 eV to 10 MeV) responsible for the spacecraft charging phenomena and transient charging effects; (3) An electron beam system able to eject electrons with from 50 eV to 3 keV in energy to attempt to correct for charging caused by environmental electrons; (4) An ion beam system able to eject ionized xenon with 1 keV and 2.5 keV energies, to attempt to duplicate charging caused by environmental electrons. These instruments will be part of the total SCATHA instrumentation which consists of engineering and environmental definition experiments. Acting in concert, these instruments will test charge neutralizing procedures and provide data to specify design criteria for future synchronous satellites.Mode of access: Internet