NOPR Collection:

A self-calibrating facility for atmospheric radars

Sat, 01 Apr 1989 00:00:00 GMT

Title: A self-calibrating facility for atmospheric radars Authors: Reddi, C Raghava; Ramkumar, Geetha Abstract: A Self-calibrating facility, necessary for routine check on the atmospheric radars being built in India, is described. The facility will ensure data of uniformly good quality and also intercomparison of data obtained over long periods. Page(s): 61-70

Laser radar monitoring of tropospheric aerosols

Sat, 01 Apr 1989 00:00:00 GMT

Title: Laser radar monitoring of tropospheric aerosols Authors: Devara, P C S; Raj, P Ernest; Londhe, A L Abstract: A bistatic laser radar (using a continuous wave argon ion laser) installed at the Indian Institute of Tropical Meteorology (IITM), Pune, for remote sounding of atmospheric aerosol characteristics has been briefly described. The day-to-day and height-time variations in the vertical distribution of aerosol number density (up to 3680 m AGL) have been studied by operating the radar on 6 clear days during nighttime in the month of April 1987. The results of study indicted the formation and redistribution of aerosol layer structure in the lower altitudes (up to 1800 m). Also, conspicuous differences in the height distribution of aerosol number density were notices between the post-sunset and pre-sunrise periods. The observed features have been explained on the basis of aerosol transport and diffusion processes occurring in the nocturnal urban atmosphere Page(s): 57-60

Photoionization balance and thermal imbalance in the equatorial and low latitude E region

Sat, 01 Apr 1989 00:00:00 GMT

Title: Photoionization balance and thermal imbalance in the equatorial and low latitude E region Authors: Swamy, A C Balachandra; Setty, C S G K Abstract: A model for studying the E region electron temperature using a newly developed profile matching technique is described. The computed profile of electron density (N_e) is matched with that of an experimental profile of N_e. The matching of the two profiles is achieved by increasing electron temperature (T_e) suitably above neutral gas temperature (T_g) for a series of fixed heights. The T_e profile is thus constructed. The computed T_e for three equatorial and low altitude stations, namely, Thumba, Peru and Arecibo, show that T_e>T_g in the height range 100-130 km with a peak near 120 km. Page(s): 52-56

Solar flare effects on 164 kHz LF wave propagation over Tashkent-Patiala path

Sat, 01 Apr 1989 00:00:00 GMT

Title: Solar flare effects on 164 kHz LF wave propagation over Tashkent-Patiala path Authors: Sayal, Anita; Singh, Darshan; Gurm, H S Abstract: Different types of sudden field anomalies (SFAs) are observed on 164 kHz long wave propagation from Tashkent (lat., 41°25´N; long., 69°12´E) to Patiala (lat., 30°20´N; long., 76°24´E) during a solar flare. Type 1 variations occur mostly from June to October, whereas Types II and III occur from November to May. The SFAs are more frequent during winter and equinoxes as compared to summer. The large X-ray flux enhancements in wavelength bands 0.5-3 Å and 1-8 Å are required for Types I and III effects to occur as compared to Type II effects and the same holds good for hardness factor. There seems to be no correlation with peak time plasma temperature of the X-ray emitting regions. Page(s): 48-51