Frequency domain analysis tools have been developed to analyse simultaneous multi-point measurements of developed space plasma turbulence. The Coherence Length technique enables the scale length for ...plasma wave structures to be measured from magnetic field measurements. The coherence length defines a length scale for the measurement of wave phenomena. Single satellite measurements can be used, the technique becoming more reliable with higher numbers of satellites. The technique is used to identify coherence lengths for waves observed in the magnetic field near the bow shock by the dual AMPTE-UKSIAMPTE-IRM satellites, and for mirror wave structures observed in the magnetic field in the magnetosheath by the dual ISEE-lIISEE-2 satellites. The Transfer Function Estimation technique enables the transfer of energy between plasma waves to be measured, from simultaneous dual-point measurements, resulting in linear growth / damping rates and second-order wave coupling. The technique is improved by replacing the Least Squares method for inversion with Regularisation. The technique is applied to simultaneous magnetic field measurements near the bow shock by the AMPTE-UKSIAMPTE-IRM satellites, where a linear instability in the wave field is identified, which is attributed to an ion anisotropy instability, and accompanying sequence of second-order three-wave coupling processes is also identified, which dissipates the energy from the linear instability. The Wave vector Determination technique enables the identification of wave vectors from simultaneous four-point measurements. The availability of four-point measurements means that the reliance on Minimum Variance Analysis, and that of only being able to use magnetic field measurements, is removed, the wave vector can be determined unambiguously directly from the magnetic field measurements. The technique can identify between waves of different frequency, and waves at the same frequency but propagating in different directions. The technique is applied to simultaneous observations of the electric field by the four-point ii Cluster II satellites, enabling the determination of the wave vector and the identification of a mirror mode structure, solely from the electric field measurements. Chapter 1 introduces the solar-terrestrial environment, briefly describing exploration of this environment by man-made satellites and listing some aims of the analysis of data collected by the satellites. Chapter 2 elaborates on what is meant by data analysis; Spectral Transforms are introduced and described, with a comparison made between Fourier Transforms and Wavelet Transforms, before a review is made of current data analysis techniques for satellite data. Chapter 3 defines and focuses attention on the objectives of this thesis, which are addressed in the following three chapters. Chapter 4 investigates the coherence length of plasma waves through use of the Wavelet Transform and the Fourier Shift Theorem. Chapter 5 makes estimates of wave Transfer Functions, replacing an established Least Squares inversion technique with a Regularisation inversion. Chapter 6 uses a method to determine wave propagation directions, from multi-satellite data, that has not been applied before due to the lack of availability of suitable data sets. Chapter 7 summarises the preceding chapters. The Appendices contain reprints of papers resulting from, and relating to, this research.
When compared to satellite detector measurements of dust particles of mass < 10^-6 g and optical meteor observations for mass > 10^-2 g, the flux of the interstitial radar meteors is discrepant: the ...radars render fluxes which seem too small by a factor of about 20-30. This has usually been explained as being due to the majority of the flux being held in low-velocity meteors which produce little ionization and hence have limited radar detectabilities. We propose an alternative hypothesis: that the discrepancy is due to wavelength-dependent effects, implying that conventional meteor radars {f > 20 MHz) only detect the lower-altitude underdense meteors. To test this we have determined the height distribution of radar meteors at 2 and 6 MHz, at which frequencies the echo ceilings are much higher than the 100-105 km limits of VHP radars. We find that the distributions peak at “105 km, fully 10 km above the peaks of VHP radars, with many meteors occurring to at least 140 km altitude. Additional observations using the powerful Jindalee radar in central Australia confirm these results, and show that the cumulative flux of particles of mass > 10"-6 g is about 9 x 10^-8 m^-2 sec^-1; this is consistent with satellite data and is over an order of magnitude larger than derived in previous radar meteor experiments.
A method to derive surface albedo from satellite measurement is developed and discussed. In this method, atmospheric correction is performed by solving the radiative transfer equation, and ...calibration coefficients for the satellite radiometer are determined by the measurements over two reference sites; i. e., sea surface and snow-coverd surface. The sensitivity study indicates that the calculated surface albedo is not sensitive to the assumed surface albedo values of the reference sites, but sensitive to the optical properties of atmosphere. The proposed method is tested over Sapporo and Tokyo area, using NOAA AVHRR data and surface albedo maps for snow-covered area and no snow-covered area are derived. The method is shown to be relevalent for the study of urban heat island.
After only a few days in orbit, the first U.S. satellite of the moon has already produced data which have provided new information about the moon's gravitational field. Results indicate that the ...spacecraft will probably not impact on the moon before it completes its photographic mission, but that it will probably do so in about 8 months. Preliminary indications are that the moon has a relatively large pear-shaped component and that the gravitational properties will be of considerable scientific interest.
Television and photofacsimile-constructed infrared pictures taken by the Nimbus I meteorological satellite between 28 August and 22 September 1964 were analyzed for indications of the pack-ice ...boundary around Antarctica. Mean ice boundaries were established around the entire continent from both TV and infrared pictures, from which were, estimated pack-ice areas of 19.81 by 10$^{6}$ and 16.78 by 10$^{6}$ square kilometers, respectively; the difference is attributed to difference in subjective discernment of a boundary.
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