Photometric measurements of surface characteristics of echo i satellite final report

Photometric measurements of Echo I satellite surface characteristic

Ground-based photometric surveillance of the passive geodetic satellite

Ground-based photometry of Passive Geodetic Earth Orbiting Satellite /PAGEOS

The modification and use of a ground-based photometer for evaluation of satellite materials

Five-color multipurpose photometer development and observations on Echo 1 and 2, Explorer 19, and Pageos

F-region ionosphere effects on the mapping accuracy of SuperDARN HF radar echoes

Structured particle precipitation in the cusp is an important source for the generation of F-region ionospheric irregularities. The equatorward boundaries of broad Doppler spectral width in Super Dual Auroral Radar Network (SuperDARN) data and the concurrent OI 630.0 nm auroral emission are good empirical proxies for the dayside open-closed field line boundary (OCB). However, SuperDARN currently employs a simple virtual model to determine the location of its echoes, instead of a direct calculation of the radio wave path. The varying ionospheric conditions could influence the final mapping accuracy of SuperDARN echoes. A statistical comparison of the offsets between the SuperDARN Finland radar spectral width boundary (SWB) and the OI 630.0 nm auroral emission boundary (AEB) from a meridian-scanning photometer (MSP) on Svalbard is performed in this paper. By restricting the location of the 630.0 nm data to be near local zenith where the MSP has the highest spatial resolution, the optical mapping errors were significantly reduced. The variation of the SWB – AEB offset confirms that there is a close relationship between the mapping accuracy of the HF radar echoes and solar activity. The asymmetric variation of the SWB – AEB offset versus magnetic local time suggests that the intake of high density solar extreme ultraviolet ionized plasma from post-noon at sub-auroral latitudes could result in a stronger refraction of the HF radar signals in the noon sector. While changing the HF radar operating frequency also has a refraction effect that contributes to the final location of the HF radar echoes

What is damaging the kidney in lupus nephritis?

Despite marked improvements in the survival of patients with severe lupus nephritis over the past 50 years, the rate of complete clinical remission after immune suppression therapy i

Influence of the ionosphere on the altitude of discrete auroral arcs

The altitude of the maximum luminosity of single, discrete auroral arcs was measured by photometric triangulation from two stations (College and Fort Yukon, Alaska) located 226km apart on nearly the same magnetic meridian. The average height of the evening aurora decreases smoothly with increasing solar depression angle (sda) from 160km near 12° sda to 100km after 18° sda. The average height remains constant until around 12° sda in the morning. This diurnal variation is similar to that of the electron density in the F region of the ionosphere. Thus, the behavior is consistent with the concept that the mean auroral electron energy increases as the ionospheric conductivity decreases due to ionospheric recombination in the evening twilight. However, the mean electron energy decreases in magnitude at dawn when the solar ionizing radiation returns and the electron density in the F region increases. The magnetospheric acceleration mechanism associated with discrete auroral arcs thus appears to be inversely proportional to the ionospheric conductivity, because the time variation of the acceleration mechanism coincides with the local F region electron density and not with any obvious magnetospheric process. Previous auroral altitude observations, using similar triangulation methods, showed that the altitude of discrete auroral arcs increases as a function of latitude. When these data are corrected for the twilight effect, the dependence of altitude on latitude disappears. Thus, the average altitude of discrete auroral arcs and, by inference the magnetospheric auroral electron acceleration mechanism, is significantly influenced by the initial ionospheric conductance