ABSTRACT:In this study, the performance of the weather research and forecasting (WRF) ARW regional model was evaluated for simulating the regional scale precipitation during Indian summer monsoon (ISM) at 30 km resolution over seven different homogeneous rainfall zones falling under different climatic (perhumid, humid, dry/moist subhumid, dry/moist semiarid, arid) regions of India. Seasonal scale simulations were made for ten summers (JJAS months) over 2000-2009 using the boundary conditions derived from the National Centers for Environmental Prediction (NCEP) reanalysis data. Sensitivity experiments were conducted with three convection schemes (Kain-Fritsch, KF; Betts-Millor-Janjic, BMJ; GrellDevenyi, GD). Simulated regional climate was evaluated by comparison of precipitation with 0.5°India Meteorological Department (IMD) gridded rainfall data over land, Tropical Rainfall Measuring Mission (TRMM) rainfall data over the ocean and atmospheric circulation fields with 1°NCEP global final analysis (FNL). Although all the simulations showed spatio-temporal rainfall patterns, BMJ had least bias towards dryness whereas KF had moist bias and GD had higher dry bias. BMJ could simulate low, moderate and high rainfall reasonably well with relatively higher correlations and threat scores, lower bias and mean absolute errors in most zones as compared to better simulation of heavy precipitation events with KF and low rainfall days alone with GD scheme. The better performance of BMJ scheme is evident owing to better simulation of surface pressure, temperature, and geopotential, lower and upper atmospheric flow fields. Simulations revealed a relatively less intensive heat, weaker low-level westerly winds, weaker north-south geopotential gradients, weaker subtropical easterlies in the El Niño years than in the La Niña years, which indicate the model is able to simulate the interannual variations in monsoon characteristics.
Various pre-treatment methods and three different media were employed for the isolation of bioactive actinomycetes from mangrove sediments of Andaman and Nicobar Islands, India. Sediments from four different sites of mangrove forest were collected and pre-treated by dry heat method, and the media were supplemented with cycloheximide 80 μg/mL and nalidixic acid 75 μg/mL. The mean actinomycetes population density in sediment samples were recorded as 22 CFU-10-6 /gm in KUA medium followed by 12 CFU-10-6 /gm in AIA medium and 8 CFU-10-6 /gm in SCA medium. A total of 42 actinomycetes were isolated, and all the isolates were evaluated for their antibacterial activity against pathogenic bacteria on two different media. Among 42 isolates tested, 22 species were found to be antibacterial metabolite producer against test bacteria namely, Staphylococcus aureus, Bacillus subtilis, Salmonella typhi and Klebsiella pneumoniae. Particularly, the actinomycete strains such as A101,
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