NOPR Collection:

Dielectric properties of black soil with chemical fertilizers at X-band

Mon, 01 Jun 2015 00:00:00 GMT

Title: Dielectric properties of black soil with chemical fertilizers at X-band Authors: Navarkhele, V V; Kapre, A K; Shaikh, A A Abstract: Dielectric properties of black soil with the addition of chemicals were measured at microwave frequency. The dielectric measurements have been achieved by using X-band set up. The dielectric properties, that is dielectric constant (') and dielectric loss (") have been measured for two frequencies (8 and 10 GHz) at room temperature. From the experimental data, it is confirmed that the dielectric constant and dielectric loss increase with increasing percentage volume of chemical fertilizers and decrease with increase in frequency of oscillation. The results also show that the dielectric constant and dielectric loss are higher for the urea than that of potassium carbonate. Page(s): 102-105

Study of pre-monsoon thunderstorms over Kalyani from radio frequency spectra

Mon, 01 Jun 2015 00:00:00 GMT

Title: Study of pre-monsoon thunderstorms over Kalyani from radio frequency spectra Authors: Bhattacharya, A B; Raha, B; Pandit, J; Sarkar, Shalini; Sarkar, Sumit; Mondal, Somasree Abstract: Lightning in the form of electromagnetic radiation, in very low frequency (VLF) and low frequency (LF) bands, is received on 1 April and 7 April 2015 from 10 kHz to 300 kHz over Kalyani during pre-monsoon thunderstorms. Their characteristics, viz. the spectral pattern and other relevant properties, are examined with the help of radio frequency (RF) spectra. Another severe thunderstorm experienced, over a wide area covering different parts of South Bengal including Kalyani, on 11 April 2013 has also been recorded in the form of integrated field intensity of atmospherics at 27 kHz receiver. After analysing, some interesting results are reported related to radio signal reception originating from lightning as electromagnetic radiation. Page(s): 96-101

Variability of ion density due to solar flares as measured by SROSS–C2 satellite

Mon, 01 Jun 2015 00:00:00 GMT

Title: Variability of ion density due to solar flares as measured by SROSS–C2 satellite Authors: Bardhan, Ananna; Sharma, D K; Kumar, Sarvesh Abstract: In the present paper the effect of solar flares on ion density has been studied. The ion densities have been measured for the period 1995-1998 using RPA payload of SROSS-C2 satellite. Solar flare data has been obtained from National Geophysical Data Center (NGDC) Boulder, Colorado (USA). The study indicates considerable decrease (1.2 to 2.8 times) in total ion density during flare time as compared to normal time. Out of four ion species, i.e. O⁺, O₂⁺, H⁺ and He⁺, the O⁺ ion density is most affected by the effects of the flare as measured by SROSS–C2. There is considerable decrease in O⁺ ion density while O₂⁺, H⁺ and He⁺ density show negligible change during flare time as compared to normal time. Furthermore, relation between change in ion density (∆N) as a response to change in ion temperature (∆T) during flare time and normal days has been estimated. A comparison of ion density obtained from SROSS-C2 with IRI–2012 during the flare time indicates an overestimation by IRI-2012. Page(s): 88-95

Correlation of foF2 and M(3000)F2 over low latitude stations during low solar activity period

Mon, 01 Jun 2015 00:00:00 GMT

Title: Correlation of foF2 and M(3000)F2 over low latitude stations during low solar activity period Authors: Nagar, Anju; Mishra, S D; Vijay, S K Abstract: This paper aims to investigate the relationship between propagation parameter M(3000)F2 and F2-layer critical frequency (foF2) during 2006-2010. Data from three low latitude stations, namely Jicamarca (12ºS, 283ºE), Kwajalein (09ºN, 167ºE) and Madimbo (22ºS, 031ºE) for the months of January (winter) and July (summer) during 2006-2010 are used for the study. It is found that the daily values of M(3000)F2 cannot be estimated from foF2 using a simple linear equation. It is concluded that that two procedures (day-to-day and hour-to-hour) do not give different results and the correlation coefficients between the daily values of M(3000)F2 and foF2 are generally lower than 0.6 and could be positive or negative. Page(s): 78-87