NOPR Collection:

Percentage contribution of atmospheric minor constituents on marine lower tropospheric ozone

Tue, 01 Jun 2004 00:00:00 GMT

Title: Percentage contribution of atmospheric minor constituents on marine lower tropospheric ozone Authors: Jana, P K; Nandi, S C; Midya, S K Abstract: A critical analysis has been made on contribution of atmospheric minor constituents on the formation of oceanic ozone at the lower troposphere. Altitudinal distributions of these constituents are also presented. Page(s): 201-205

Estimation of dielectric constant of soil from the given texture at microwave frequency

Tue, 01 Jun 2004 00:00:00 GMT

Title: Estimation of dielectric constant of soil from the given texture at microwave frequency Authors: Ranjan, Vivek; Bohra, Chetan; Calla, O P N; Naik, Gangadhar L; Hasan, Waseem; Bali, Harmeet Singh Abstract: Value of the dielectric constant of a given sample of soil has been estimated from its known texture by multiplying the given texture with the constants at different microwave frequencies. The model is tested for four samples of soil: one sample from Uttar Pradesh and three samples from Kashmir in India. Page(s): 196-200

Attenuation of ULF-VLF seismo-electromagnetic signals and their propagation to long distances

Tue, 01 Jun 2004 00:00:00 GMT

Title: Attenuation of ULF-VLF seismo-electromagnetic signals and their propagation to long distances Authors: Singh, Raj Pal; Singh, Birbal; Kushwah, Vinod Kumar; Chauhan, Ram Vir Singh Abstract: Using a two-layer crust model between the source region and earth surface, the attenuation of seismo-electromagnetic signals is calculated. Results show that attenuation of Ultra Low Frequency (ULF) signals is very low and they can penetrate the crustal region to enter the atmosphere and ionosphere over the epicentral area of the earthquakes. However, the attenuation increases steeply in the c rust for the ELF and VLF ranges of signals. These results are utilized to discuss the propagation mechanism of VLF signals (f = 3 kHz), which are recorded at Agra by employing a borehole antenna during the periods of Chamoli earthquakes in India and large magnitude earthquakes in Afghanistan. It is suggested that these VLF signals propagate upward and find windows of very low conductivity in the skin layer through which they get transmitted to the atmosphere. They the n propagate to the observing station at Agra through earth -ionosphere waveguide. Page(s): 189-195

Variations in the concentrations of ionic species in rain events at Pune

Tue, 01 Jun 2004 00:00:00 GMT

Title: Variations in the concentrations of ionic species in rain events at Pune Authors: Chate, D M; Rao, P S P; Momin, G A; Safai, P D; Ali, K; Tiwari, S; Praveen, P S Abstract: In the present work, evolutions of the concent rations of major neutralizing agents (Ca²⁺ and NH₄⁺) and acidic species (SO₄^2- and NO₃^-) are computed with Slinn's model using the initial number concentrations of particle size distributions measured at Pune during 1998-1999. Theoretically predicted ionic concentrations are compared with observed ionic concentrations in the sequential samples collected in the rain events at Pune. Also, equivalent ratios [(SO₄^2- + NO₃^-)/(Ca²⁺ + NH₄⁺)] are computed theoretically to study the neutralizing capacity of the atmosphere during precipitation events and compared them with observed ones. The variation of observed equivalent ratios with accumulated rain (mm) indicated that acidic components are always neutralized with neutralizing species. Page(s): 185-188