NOPR Collection:

Some Results of Ozone Measurements during Indo-USSR Ozone Campaign 1987

1988-10-01T00:00:00Z

Title: Some Results of Ozone Measurements during Indo-USSR Ozone Campaign 1987 Authors: Seshadri, N; Sharma, A K; Joseph, K T Abstract: The data collected during the intensive observation period of the second phase of Indo-USSR Ozone Campaign conducted at the TERLS, Trivandrum, in December 1987 have been utilized to study various interesting features of ozone variations over India. The effect of the weather systems including western disturbances on the total ozone and vertical distribution of ozone has been studied. A comparison of vertical ozone profiles obtained by Umkehr method and ozonesonde at New Delhi and Pune has also been made. Surface ozone measurements recorded at the six Indian network stations have been analyzed. Page(s): 188-192

Model Calculations of Nightside Ionosphere of Venus: Ionic Composition

1988-10-01T00:00:00Z

Title: Model Calculations of Nightside Ionosphere of Venus: Ionic Composition Authors: Haider, S A Abstract: Model calculations of nightside ion and electron densities have been carried out for the ionosphere of Venus and compared with the results obtained from Pioneer Venus ion mass spectrometer and Venera 9 and 10 radio occultation measurements. The generalized yield spectrum approach has been used for the calculation of ion production rates in the ionosphere of Venus by using measured Venera 9 electron fluxes. Coupled continuity equations for ionic species CO, CO⁺ , H⁺, NO⁺ , C⁺ , N, N⁺ , He⁺ ,O⁺ and O have been solved by assuming photochemical steady state conditions. The results obtained for electron density show good agreement with the measured densities obtained by PVO mass spectrometer. However, at higher altitudes the present results are about a factor 2 less than the results reported by Venera 9 and 10 measurements. The electron density at the layer peak calculated in the present work is 1 x 10⁴ cm^-3, a value comparable to that reported by Venera 9 and 10 measurements during solar cycle minimum. Page(s): 183-187

Diurnal Distributions of Multipath Fading on 11 GHz Line-of-Sight Link in Northern India

1988-10-01T00:00:00Z

Title: Diurnal Distributions of Multipath Fading on 11 GHz Line-of-Sight Link in Northern India Authors: Banerjee, P K; Chakrabarti, Sumana; Singh, Jagdish; Narang, N K Abstract: Signal in 11GHz band transmitted over a 27.75 km overland path was continuously monitored throughout the month of July 1987 for both vertical and horizontal polarizations. Two types of fades have been observed on the link which have been identified and explained on the basis of movement of atmospheric boundary layer. It has also been observed that atmospheric multipath occurrence frequency is insensitive to the state of polarization. Page(s): 179-182

Propagation of Anomalous Long-distance TV Signals and Artificial Modification of Ionosphere

1988-10-01T00:00:00Z

Title: Propagation of Anomalous Long-distance TV Signals and Artificial Modification of Ionosphere Authors: Saksena, R C Abstract: Data obtained by systematic monitoring of anomalous long-distance TV signals at Delhi during May 1979-April 1981 have been analysed. An attempt has been made to identify various modes of propagation responsible for these signals. It has been observed that the percentage of TV receptions is higher than expected from known natural modes via tropospheric and ionospheric paths. It has been suggested that these unexplained TV signals are due to propagation via artificially modified ionosphere caused by high power, high frequency broadcast transmitters operating in the neighbourhood. Page(s): 172-178