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1
artículo
We present a method for deriving horizontal velocities, vertical velocities, and in-beam incidence angles from radar interferometer data. All parameters are calculated from the slope and intercept of straight lines fitted in a least-squares sense to the variation of the signal phase as a function of radial velocity for each pair of receiving antennas. Advantages of the method are that the calculations are computationally fast and simple, and the analysis leads to relatively simple expressions for the uncertainty in the velocity measurements.
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documento de trabajo
In the period from 13 Sept to 20 Sept 1979, the 430 MHz radar system at the Arecibo Observatory was used to study profiles of vertical velocity in developing and mature thunderstorms during the afternoon hours. During the eight day period, five days produced significant convective activity. The great sensitivity of the Arecibo radar facility al­lowed vertical velocities to be measured up to an altitude of 20 km. Since the tropopause over Puerto Rico is at an altitude of approximately 14 km at that time of year, the lower part of the stratosphere was also observed during the period of cloud development. Many studies have been carried out using Doppler radars to probe the interior of convective cells (see Wilson and Miller, 1972 for an excellent review and bibliography; also Battan, 1973). This is particularly true of radars operating at shorter wavelengths of 3 or 10 cm whích are more s...
3
artículo
First results from the JULIA radar at Jicamarca are presented. These include coherent scatter observations of the equatorial electrojet and of 150-km echoes. Interferometry is used to measure the zonal drift rate of kilometer scale waves in the electrojet as functions of altitude. A technique for estimating the background zonal electric field from the interferome­try data is described. The electric field estimates can be calibrated against the Doppler speed of the 150-km echoes when the latter are present. The kilometer-scale wave drifts sometimes exhibit large-amplitude, periodic height variations with vertical wavelengths of about 10 km. These signatures are reminiscent of the wind pro­files measured with chemical release techniques in the lower thermosphere during the Guará campaign.
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ponencia
Diapositivas presentadas en: ISEA 12 - 12th International Symposium on Equatorial Aeronomy, May 18-24, 2008. Crete, Greece.
5
artículo
Sounding rocket experiments were conducted during the NASA EQUIS II campaign on Kwajalein Atoll designed to elucidate the electrodynamics and layer structure of the postsunset equatorial F region ionosphere prior to the onset of equatorial spread F (ESF). Experiments took place on 7 and 15 August 2004, each comprised of the launch of an instrumented and two chemical release sounding rockets. The instrumented rockets measured plasma number density, vector electric fields, and other parameters to an apogee of about 450 km. The chemical release rockets deployed trails of trimethyl aluminum (TMA) which yielded wind profile measurements. The Altair radar was used to monitor coherent and incoherent scatter in UHF and VHF bands. Electron density profiles were also measured with rocket beacons and an ionosonde. Strong plasma shear flow was evident in both experiments. Bottom-type scattering laye...