Life cycle characteristics of deep cloud systems over the indian region using INSAT-1B pixel data

A detailed study of deep cloud systems (denoted by CSs) over the Indian region using INSAT-1B pixel data is presented. The life cycle characteristics of CSs are examined, including their preferred regions of formation and dissipation, frequency of occurrence, life duration, and speeds of propagation. A new automatic algorithm to track cloud systems has been developed that takes into account the mergers and splits in CSs. The algorithm is based on a combination of the maximum allowable displacement of a CS in 3 h and area overlap. The choice of the minimum size for CS is fixed at 4800 km2. The temperature threshold is varied from 201 to 261 K. It is observed that majority of CSs decay within a couple of hundred kilometers from where they form. There is a bimonthly modulation of the areal extent of more frequent convection. The number of CSs increases approximately linearly with threshold temperature up to 251 K. Tracking results are not very sensitive to the criterion chosen for identifying the successor in cases of multiple candidates, except for CSs that live longer than 36 h. Mean speeds of propagation of CSs range from 7 to 9 m s-1

Structural and dielectric properties of 0.75PMN-0.25PT relaxor ferroelectrics with different frequencies at room temperature

18-21In the present work, the composition of 0.75PMN-0.25PT solid solution was synthesized by columbite precursor method with multiple heat treatments at 920°C and 1200 °C. XRD data shows the perovskite structure with minimized pyrochlore phase and intense peaks. It has been observed that the pyrochlore phase can be reduced by increase in sintering temperature. SEM report shows the polygonal, dense and compact grain boundaries. Dielectric study shows the effect of variation in frequency to the dielectric constant and electrical conductivity at room temperature

Estimation of some essential, non essential toxic and toxic elements in some Indian black tea sold in market by ‘ICP-MS’ and their risk assessment.

226-230Tea ‘Camellia sinensis’ is the most consumed non essential, non alcoholic liquid in the world. Black Tea finds its place in Indian culture as well as a part of diet of Indian population. Tea is known for its relaxing effect and therapeutic use as it contains bioactive polyphenols, amino acids, caffeine, theophylline and volatile organic compounds. Significant research efforts have been carried out on Tea for its health benefits. However, some ill effects also have been reported. Present work has been carried out to determine the essential, non essential toxic and toxic elements namely Iron (Fe), Copper (Cu), Cobalt (Co), Chromium (Cr), Aluminum (Al), Arsenic (As) and Lead (Pb); health risks associated with them among adult population. For this, the twelve well known and most selling (most consumed) Tea brands available in local Indian market were selected and analyzed by sophisticated instrument ICP-MS

Structural and frequency dependent dielectric properties of 0.90PMN-0.10PT ferroelectrics at room temperature

188-192In the present study, the composition of (1-x)PMN-(x)PT for X=0.10 binary solid solution was synthesized by double step columbite precursor method with multiple heat treatments at different temperatures. XRD analysis shows the single perovskite phase with minimized pyrochlore phase. The intense peaks of XRD pattern indicates the perovskite phase of composition. It was observed that the pyrochlore phase in the material can be reduced by increase in sintering temperature and proper stoichiometry. SEM micrograph shows the polygonal, dense and compact grain boundaries. Room temperature frequency dependent nature of Dielectric constant and tangent loss of prepared composition was also measured

Diurnal variation of deep cloud systems over the Indian region using INSAT-1B pixel data

Among the various time scales of deep clouds, diurnal variation is found to be prominent over the tropics. The present study examines the diurnal variation in the number and area cover associated with the cloud systems over the tropical Indian region using INSAT-1B pixel data. Three periods, namely, April-May 1988, July-August 1988, and January-February 1989 are considered. The dependence of diurnal characteristics on the temperature threshold, life duration and size of cloud systems, and land-sea contrast has been explored. The diurnal characteristics of cloud systems living for more than a day have been studied for the first time. It is shown that cloud systems exhibit strong diurnal dependence at the coldest temperature threshold used (201 K). Also, the diurnal variation is more for larger cloud systems and for longer living systems. In general,more deep cloud activity is found from the satellite data during the predawn and early morning hours. Precipitation is enhanced during morning to early noon hours.Further, using data from a recent field experiment, clear evidence of diurnal variation in precipitation over the Bay of Bengal is also presented

Diurnal variation of deep cloud systems over the Indian region using INSAT-1B pixel data

Among the various time scales of deep clouds, diurnal variation is found to be prominent over the tropics. The present study examines the diurnal variation in the number and area cover associated with the cloud systems over the tropical Indian region using INSAT-1B pixel data. Three periods, namely, April-May 1988, July-August 1988, and January-February 1989 are considered. The dependence of diurnal characteristics on the temperature threshold, life duration and size of cloud systems, and land-sea contrast has been explored. The diurnal characteristics of cloud systems living for more than a day have been studied for the first time. It is shown that cloud systems exhibit strong diurnal dependence at the coldest temperature threshold used (201 K). Also, the diurnal variation is more for larger cloud systems and for longer living systems. In general, more deep cloud activity is found from the satellite data during the pre-dawn and early morning hours. Precipitation is enhanced during morning to early noon hours. Further, using data from a recent field experiment, clear evidence of diurnal variation in precipitation over the Bay of Bengal is also presented

P8.6 VALIDATION OF INFRARED AZIMUTHAL MODEL AS APPLIED TO GOES DATA OVER THE ARM SGP

Precise knowledge of the radiation budget i

Validation of Infrared Azimuthal Model as Applied to GOES Data Over the ARM SGP

The goal of this research is to identify and reduce the GOES-8 IR temperature biases, induced by a fixed geostationary position, during the course of a day. In this study, the same CERES LW window channel model is applied to GOES-8 IR temperatures during clear days over the Atmospheric Radiation Measurement-Southern Great Plains Central Facility (SCF). The model-adjusted and observed IR temperatures are compared with topof- the-atmosphere (TOA) estimated temperatures derived from a radiative transfer algorithm based on the atmospheric profile and surface radiometer measurements. This algorithm can then be incorporated to derive more accurate Ts from real-time satellite operational products