Sasikumar Vairelil

Centre for Earth Science Studies | CESS · Division of Atmospheric Sciences

Rain drop size distribution (DSD) measurements at different heights were made using a micro rain radar (MRR) at Thiruvananthapuram (latitude: 8.3° N, longitude: 76.9° E). Rain DSD data obtained from the MRR have been compared with a Joss–Waldvogel impact-type disdrometer (RD-80) deployed nearby and found to have good agreement. The analysis uses da...

This study aims to investigate the characteristic features of cloud base height (CBH) over Thiruvananthapuram during different seasons. CBH data were used for the present work derived from the Vaisala Laser Ceilometer, CL31 (VLC) installed at the campus of the Centre for Earth Science Studies, Akkulam (8.29° N, 76.59° E, 15 m above sea level). The...

Rain drop size distribution (DSD) was measured at four places in Southern India {Thiruvananthapuram, Kochi, Munnar and Sriharikota (SHAR)} using a Joss-Waldvogel (JW) impact type disdrometer. The data for each minute were corrected for dead time errors and rain rate was computed from the corrected data. The data for a whole month were then sorted a...

A Joss-Waldvogel impact type disdrometer was installed at four different locations in the Indian peninsula during various periods from 2001 till date. The data are analysed to study the nature of rain drop size distribution (DSD) in this region. Out of the three well known distributions that describe DSD, namely, the Marshall-Palmer, Gamma and Logn...

The diurnal and spatial variation of concentration of aerosol particles in South India is studied and presented in this communication. Concentration of condensation particles was determined using condensation particle counter (CPC-3007) from different geographical stations, such as coastal, midland and highlands. For each geographical location, we...

Rainfall intensities measured at a few stations in Kerala during 2001-2005 using a disdrometer were found to be in reasonable agreement with the total rainfall measured using a manual rain gauge. The temporal distributions of rainfall intensity at different places and during different months show that rainfall is of low intensity (<10 mm/hr), 65% t...

A Joss-Waldvogel type disdrometer was installed at Thiruvananthapuram, Kochi, and Sreeharikotta (SHAR) during various periods. This paper presents results from the analysis of the data. Drop Size Distribution (DSD) and rainfall rate for each minute were computed from the disdrometer data, and the entire data for each month were sorted by rainfall r...

Rainfall intensity and rain drop size distribution were studied using TRMM data and a Joss-Waldvogel type disdrometer installed at Kochi Lat 9 9 N Long 76 2 E 15 m amsl and Munnar Lat 10 1 N Long 77 1 E 1500 m amsl during the south-west monsoon period The stations are situated in Kerala an elongated coastal state in the south-west tip of peninsular...

Acoustic noise beyond a level is harmful. The fact that a regulation to abate noise is in force should remove all doubts about the damaging aspect of noise pollution. The cities being the most polluted, the main thrust is towards estimating the level of pollution in the cities. Of all kinds of noise, traffic noise is known to contribute the maximum...

Drop size distribution was measured at Thiruvananthapuram, Kerala State, India, during April, June and July 2001 using a Joss-Waldvogel type disdrometer. The instrument gives the number of drops in 20 size classes ranging from 0.3 mm to > 5 mm. Each month's data were sorted, based on rainfall intensity, into periods of rainfall intensity < 1 mm/hr,...

On 25 July 2001, around 8:30 a.m., red precipitation fell in parts of Changanasserry town in Kerala State, India. The colored rain covered an area of about 2 km2. Since water supply had been disrupted in the region, many people had left vessels outside to collect rainwater for use. When examined, samples of this water were found to contain micro-or...

Atmospheric electrical conductivities have been monitored at a coastal site having a large deposit of radioactive minerals. Conductivities were also monitored at two other sites, one coastal and the other inland, both non-radioactive. The ratio of conductivity at the radioactive site to that at the others is about 6, in agreement with the ratio of...

Atmospheric electrical polar conductivities were measured using a Gerdien condenser mounted on an aircraft. These surveys, conducted over the western coast of South India, have detected enhanced conductivities associated with the placer deposits of the radioactive mineral monazite found in this region. The data reflect the variation in the level of...

This paper discusses the results from four rocket experiments conducted from Thumba, India, during the Indian Middle Atmosphere programme (IMAP). These rockets carried instrumented Gerdien Condenser payloads to measure ion densities and their mobilities. In the first two flights only positive ion measurements were attempted while the other two meas...

The theory of the atmospheric electric circuit and a discussion of the fair-weather electrical are presented. The ion concentration, mobility, conductivity, and electric field altitudinal profiles are explained. An outline of the electrical processes inside thunderstorms along with a description of the lightning strike are included. (Author)

A balloon-borne force-aspirated Gerdien condenser measurement gives the conductivity profile from the surface upwards. The conductivity, instead of continuously increasing from the surface, decreases initially up to 2 km and then increases. This is due to the combination of the ionization due to galactic cosmic rays and surface radioactivity/radioa...

Polar conductivities, ion densities and mobilities measured in three balloon experiments are reported here. Of these, two were made with self-aspirated and one with pumped Gerdien condensers. These measurements were carried out over the period 1985-1986. Both positive and negative ion data were obtained only in the first flight. Positive ions were...

Atmospheric ion densities, mobilities, and electrical conductivities were measured by self-aspiring Gerdien condensers, carried on rockets and balloons deployed as a part of the Indian Middle Atmosphere Program. The results of rocket measurements showed that the ion density reaches a minimum at a height around 62 km, and that, below this height, it...