NOPR Collection:

Study on compact meandered microstrip antenna with a shorting pin

Sun, 01 Feb 2004 00:00:00 GMT

Title: Study on compact meandered microstrip antenna with a shorting pin Authors: Yani, R M; Farida, S F; Hunagund, P V Abstract: Realization of a compact configuration by combining the techniques of patch meandering and shorting pin loading for rectangular microstrip antenna is reported in this paper. The patch meandering is made by inserting number of slits at the radiating edges of microstrip patch. Typical experimental results of the proposed antenna are presented. Through the experimental results it is clear that the meandered microstrip patch with shorting pin will resonate at much lower frequency compared to the conventional microstrip patch of same size. Page(s): 71-73

Sensitivity of brightness temperatures to the oceanic surface roughness and rainfall for TRMM and IRS-P4-MSMR radiometric channels over the Indian Ocean

Sun, 01 Feb 2004 00:00:00 GMT

Title: Sensitivity of brightness temperatures to the oceanic surface roughness and rainfall for TRMM and IRS-P4-MSMR radiometric channels over the Indian Ocean Authors: Gairola, R M; Varma, A K; Pokhrel, Samir; Gohil, B S; Agarwal, V K Abstract: Upwelling microwave radiances at the top of the atmosphere originate partly from the oceanic/land surfaces and partly from atmospheric constituents. Radiative transfer simulations have been carried out for the Tropical Rainfall Measuring Mission (TRMM)-Microwave Imager (TMI) and Indian OCEANSAT-Multichannel Scanning Microwave Radiometer (MSMR) radiometric frequencies for varying winds, under clear sky (non-raining) and raining conditions. Both emission and scattering based radiative transfer simulations are carried out for typical atmospheric profiles over the North Indian Ocean during the monsoon season. The simulation results match reasonably well with the real observations from TRMMTMI and MSMR channels that represent a variety of oceanic and atmospheric conditions during the south-west monsoon season. The main purpose of simulations is to delineate the frequencies that are most sensitive (as far as brightness temperatures are concerned) to the ocean surface and rainfall characteristics. This effort will contribute for the combined use of different sensors to retrieve geophysical parameters with better accuracy. Page(s): 61-70

Effects of ultraviolet-C radiation on isolated fish scale melanophores

Sun, 01 Feb 2004 00:00:00 GMT

Title: Effects of ultraviolet-C radiation on isolated fish scale melanophores Authors: Ali, Sharique A; Ali, Ayesha S; Ali, S Nasir; Jain, Ravi Abstract: The effects of ultraviolet-C radiation on isolated fish scale melanophores are studied. The responses of melanophores were measured by mean melanophores size index (MMSI). At a temperature range of 27-29°C, the melanophores were exposed for varying durations ranging from one min to 60 min, to a direct source of ultraviolet-C radiation of wavelength 254 nm. It was found that the exposure of 30 min of UV-C radiation produced the highest effects on the melanophores of C. punctatus, where the MMSI reached a peak value of 8.351 ± 0.3798. The melanophores had become highly dispersed, with their cellular processes extending maximally. Page(s): 58-60

Lidar observations of middle atmosphere temperature variability over low latitude

Sun, 01 Feb 2004 00:00:00 GMT

Title: Lidar observations of middle atmosphere temperature variability over low latitude Authors: Krishnaiah, M; Raju, U Jaya Prakash; Kumar, Y Bhavani; Raghunath, K; Kumar, V Siva; Rao, P B; Murthy, B V Krishna; Sasi, M N; Parameswaran, K; Murthy, K Krishna; Nair, Prabha Abstract: In this paper, 246 Rayleigh lidar observations covering the altitude range of stratosphere and mesosphere collected during the period March 1998- December 2001 (37 months) using Indo-Japanese Lidar at National MST Radar Faculty (NMRF), Gadanki (13.8°N, 79.2°E), India, are presented. The atmospheric density profiles were derived. Using the limited database, a climatological structure of temperature over a tropical site giving seasonal variations of upper stratosphere and mesospheric region is also presented. It has been observed over Gadanki, that the stratopause is quite broad and occurred in the range of 43-58 km with the temperature maximum observed in winter and equinox periods. A semi-annual variation is seen clearly around 70 km with maxima at May/June and Dec/Jan. Mesospheric temperature shows strong inversion very often. The average climatology over 37 months period is found to compare well with a reference atmosphere model (MSISE 90). The observed temperature is, in general, colder throughout the year in the 30-45 km range and warmer in summer at 70-80 km as compared to the model derived values. The present study suggests that the 45-55 km region is less affected by temperature variability, which is well suited for the detection of possible temperature trends Page(s): 50-57