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Paul, A. K.

Publications and source records attributed to Paul, A. K..

9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Off Median Phenomena and International Reference Ionosphere; COSPAR International Scientific Symposium, Trieste, Italy, Oct. 19-22, 1993

The main subject of the symposium was 'off-median phenomena'. The title denotes a range of problems that are rarely considered in 'pure science' studies of the ionosphere. The appearance of regular ionospheric variations is well known. Most of these depend on evident solar-geophysical influences like day and night, solar zenith angle, the seasons, geomagnetic control, solar activity, etc. Applicants and theoreticians as well used to work with monthly medians so that the in fact existing and quite important day-to-day variability is systematically overlooked. It is evident that a descriptive model like the International Reference Ionosphere (IRI) would be inadequate if this variability were denied. Interesting contributions from the symposium on 'off-median phenomena' and the IRI are presented.

Rawer, K.↗
NASA NTRS1975

Electron density profiles from ionograms - Underlying ionization corrections and their comparison with rocket results

Electron density profiles from nine daytime rocket flights at Wallops Island, Va., conducted at high and low levels of solar activity are compared with profiles calculated by inversion of ionograms obtained at the same times and location. Sources of error and uncertainty in the ionogram inversion are discussed, as are means for their amelioration. In most cases, agreement between the two kinds of measurement within a few percent in electron density and within a few percent of a scale height can be achieved.

Wright, J. W.↗
NASA NTRS1973

Electron density profiles from ionograms - Comparisons with rocket profiles.

From a series of ten rocket flights at Wallops Island conducted by the University of Illinois, detailed electron density profiles are available in the altitude range 60-120 km. Concurrent ionograms from a nearby conventional ionosonde of good sensitivity and precision, have been reduced to N(h) profiles by the NOAA methods. Special attention is given to the needs for accurate ionosonde calibration, proper ionogram interpretation, and corrections for underlying ionization, 'valley' ionization, and effects of lateral-gradients. Proper corrections in the present cases yield profiles by ionogram inversion which agree to within a few percent in density, and a few hundred meters or less in height, with the rocket results.

Wright, J. W.↗
NASA NTRS1972

The mathematical-physical problem of P prime(f) to N(h) inversion for anisotropic media

The requirements for a numerical inversion method to calculate electron density profiles from ionograms are discussed. A systematic investigation about the independence of the two magnetoionic components shows that the extent to which the range of ambiguity can be reduced depends mainly on the magnetic latitude. Error estimates and first-order corrections for less elaborate methods are included.

Paul, A. K.↗