Paul C. Yuen

A tsunami warning system using an ionospheric technique

Earthquakes generate Rayleigh waves which travel along the surface of the earth about 20 times faster than the potentially destructive tsunami (if one is also generated) and reach distant points several hours before the tsunami. The Rayleigh wave excites an upward-propagating acoustic wave which, because of the exponential decrease in air density with height, increases to a large amplitude at ionospheric heights and produces ionization density changes in the ionosphere proportional to the amplitude and form of the wave. HF radio signals reflected from the ionosphere are Doppler-shifted by these motions and can be processed to produce a record which is a faithful reproduction of the Rayleigh wave. By analyzing the ionospheric record and tracing the Rayleigh wave back to the earthquakes epicenter, the characteristics of the earthquake can be determined. This information can then be used to deduce the probability that the earthquake generated a tsunami Instrumentation for a tsunami warning system based on this method is simple and inexpensive.

SEASONAL VARIATIONS IN IONOSPHERIC TOTAL ELECTRON CONTENT.

Abstract Total ionospheric electron content has been measured continuously since September 1964 by observing the Faraday rotation of a linearly-polarized wave received from the geostationary satellite Syncom III. Results of one years observation at the University of Hawaii (20° N) are presented in the form of monthly mean curves. The seasonal trend observed is that the largest diurnal peaks in daytime content tend to occur during the equinoxes and the smallest diurnal peaks tend to occur during the solstices. The winter night-time content remains nearly constant at about 0.3 × 10 17 electrons m 2 . During the summer months, however, the night-time content is about twice that of winter nights, and the decay rate is greater. Although daytime variations in electron content resemble those of N peak , significant differences are observed. These are illustrated by curves of slab thickness vs. time. In general, the slab thickness curves exhibit strong seasonal dependence. However, the late afternoon values are nearly the same throughout the year. In the winter, large pre-dawn and post-sunset peaks occur in the slab thickness curves. In the summer months a mid-morning peak is observed.

The ionospheric effects of geomagnetic sudden commencements as measured with an HF Doppler sounder at Hawaii

Abstract The effects of sudden commencements on the frequency shifts of an HF Doppler sounder have been investigated during the period from January 1967 to June 1970 using the Doppler frequency data obtained at the University of Hawaii and geomagnetic data obtained at Honolulu. It was found that if the ionospheric conditions are such that an F-layer reflected wave can be received, almost all the SCs cause Doppler frequency shifts. The effects can be classified into four types: SCF(+−), SCF(−), SCF(−+), and SCF(+). The amplitude of the positive spike scaled from SCF(+−) shows a linear frequency dependence and a positive correlation with the amplitude of the major impulse of the SC. A linear correlation also exists between the amplitude of the positive spike and the maximum negative frequency shift which follows it.

Heating of the low-latitude upper atmosphere caused by the decaying magnetic storm ring current

Abstract This study investigates the charge-exchange mechanism by which part of the energy contained in the magnetic storm ring current is injected into the low-latitude upper atmosphere and contributes to the energy balance in this region. The resulting temperature perturbation is estimated for a specific magnetic storm event and compared with that deduced from satellite drag data. It is found that the charge-exchange mechanism gives the correct temporal behavior of the magnetic storm associated changes in the upper-atmospheric temperature but cannot account for the magnitude of the observed temperature perturbation. An upper bound to the contribution of this mechanism to the low-latitude geomagnetic activity effect is estimated to be 30 per cent during a large magnetic storm.

Electron content power spectral estimates: Periods of 2 days to 12 year

Abstract The power spectra of the daily peak electron content measured at Hawaii are estimated via covariance estimations, bivariate autoregressive estimations and fast Fourier transforms for a year of data close to minimum solar activity (1965) and a year of data close to maximum solar activity (1969). The strong peaks about 6 days and 15 days in the 1965 and 1969 power spectra, respectively, suggest an influence of the interplanetary magnetic sector structure on the electron content at low latitude (21·3°N, geographic). The daily solar flux ( Sa ) at 2800 MHz of 1965 and 1969 are analysed similarly. The decrease in energy content with period range of 3–7 days in the 1969 Sa power spectrum supports the above point of view.

Dst and SD variations of electron content at low latitude

Abstract Electron content data obtained during 1965–1970 at the University of Hawaii have been analyzed statistically to obtain Dst and SD variations in electron content during strong and weak SC geomagnetic storms. The characteristic variations of Dst and SD are described and their qualitative explanations given. It appears that the altered meridional thermospheric neutral air winds generated by heating of the upper atmosphere at high latitude and the changes of the neutral atmospheric compositions due to the increase in local temperature during the geomagnetic storms play important roles in causing Dst and SD variations of the electron content.

The use of f0F2 data to remove the ambiguity in total electron content data

Abstract The use of f 0 F 2 data to remove the ambiguity present in total electron content data obtained by measuring the Faraday rotation of signals from geostationary satellites is discussed. Plots are presented relating content and f 0 F 2 at Hawaii on a monthly basis. Analysis of the data shows that content does not vary as ( f 0 F 2) 2 as predicted by a Chapman layer with constant scale height, but varies as ( f 0 F 2) 2(1− p ) with the exponent exhibiting both seasonal and long-term changes.

Well test analysis of HGP-A

1979 SPE-AIME California Regional Meeting, Venture, CA, April 18 to 20, 1979. Copyright 1979, American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

THE PACIFIC INTERNATIONAL CENTER FOR HIGH TECHNOLOGY RESEARCH

ABSTRACT The Pacific International Center for High Technology Research (PICHTR) is an organization dedicated to research in advanced technologies pertinent to the Pacific and Asian region. PICHTR provides nations throughout the Pacific a unique opportunity to work together on programs of common interest. The Centers location in Hawaii permits projects which can take advantage of its central geographic position, oceanic site, and multi-cultural mix. In addition to computer and information technology, marine robotics, ocean thermal energy conversion, hydrogen from renewable energy, tropical biotechnology, and Pacific Basin education and training activities have been selected as initial high priority research fields.

Hawaii Geothermal Project: HGP-A Reservoir Engineering

Department of Energy, Contract EY-76-C-03-1093; Energy Research and Development Administration, Contract E(04-3)-1093; National Science Foundation, Grant GI 38319; State of Hawaii, Grants RCUH 5774, 5784, 5942; County of Hawaii, Grant RCUH 5773; Hawaiian Electric Company, Grants 5809, 5828.