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Shimla, India

Singh M.,Meteorological Center
Journal of Agrometeorology | Year: 2011

The study conducted using 20 years total winter precipitation and snowfall data of Shimla (Himachal Pradesh) for winter season (December to March) shows that the total precipitation and snowfall for all the months have a decreasing tendency, the highest being for the month of January. The total precipitation and snowfall for different months were found to have decreased in the second decade under study by 6 to 36% and 16 to 86%, respectively. The beginning of snowfall season did not show any delay. However the season is tending to end earlier by about 12 days per decade. The decadal analysis shows that the average date of ending of the snowfall season has advanced by two weeks in the second decade compared to the first decade. The analysis indicates a potential adverse impact on the river flow and agricultural/horticultural production in Himachal Pradesh and other states down stream. Source

Agnihotri G.,Meteorological Center | Dimri A.P.,Jawaharlal Nehru University
Meteorological Applications | Year: 2015

Southern peninsular India experiences widespread thunderstorm activities during the pre-monsoon season due to the presence of a north-south trough, an easterly trough, and low pressure areas over the surrounding Indian Seas. In March 2008, southern peninsular India received unusual heavy rains because of the interaction between a large amplitude easterly trough and a mid-latitude westerly trough during 12 to 14 March, and because of the formation of a low pressure system over the Arabian Sea during 21 to 24 March. Simulation of these two heavy rainfall events is attempted using the Weather Research and Forecasting (WRF) model. The model's performance is studied in terms of the wind, pressure, movement of these synoptic scale systems, moisture and rainfall fields. Results indicate that this model has the capability to predict the movement of both easterly and westerly troughs and to simulate low pressure very well. The model is able to capture the areas of precipitation maxima in both the cases. The bias score is found to be more than 1 in precipitation thresholds up to 35mm and less than 1 in precipitation thresholds above 35 mm. The maximum values of critical success index (CSI) and equitable threat score (ETS) are 0.49, 0.32 and 0.42, 0.13 in 24 and 48h forecasts, respectively, in Case 1 and 0.69, 0.23 and 0.71, 0.19 in Case 2. The values of CSI and ETS drop considerably above the 30mm rainfall threshold in both 24 and 48h forecasts showing that the model performs better in lower rainfall thresholds. © 2015 Royal Meteorological Society. Source

Lakshminarayanan R.,Meteorological Center
International Journal of Meteorology | Year: 2014

This article studies the rainfall in Kerala, a state in southwest India on the Malabar Coast. 2012 was a remarkable year with the annual rainfall the lowest since 1901. This deficit led to water scarcity and issues with power supplies. ©THE INTERNATIONAL JOURNAL OF METEOROLOGY. Source

Agnihotri G.,Meteorological Center | Mohapatra M.,Mausam Bhavan
Meteorological Applications | Year: 2012

Karnataka, a State in south peninsular India, receives 73% of its annual rainfall during the southwest monsoon season. Because of the complex physiographical features, the rainfall pattern over the State shows large spatial variation from 50 to 350 cm. The coefficient of interannual variation of the monsoon rainfall is about 15% over coastal Karnataka (CK) and between 20 and 30% over interior Karnataka. It is, therefore, a difficult task to predict the location specific daily rainfall over Karnataka. In this study, an attempt has been made to develop an objective tool for forecasting the occurrence and non-occurrence of precipitation during a 24 h period for the 19 stations in Karnataka during the monsoon season. The probability of precipitation (POP) model is developed using forward stepwise regression with the available surface and upper air parameters from synoptic and radiosonde and radio wind stations in and around Karnataka as potential predictors. The POP model has been developed based on the data from 1981 to 1996 and verified with the data from 1997 to 2002. Different skill scores are computed using a yes/no contingency table. The POP model performs very well, with percentages of correct (PC) forecasts for occurrence/non-occurrence of precipitation being 57-91% for the independent data. Comparing the results of the POP model with that of the conventional method of forecast for Bangalore City, the PC forecasts improves from 44 to 56% with the use of the POP model. © 2011 Royal Meteorological Society. Source

Seetharam K.,Meteorological Center
Mausam | Year: 2015

The phenomenon of the “ElNino” is well known at least for more than 100 years. Many scientists and investigators showed that the equatorial pacific, especially the East Pacific SSTs, have an influence on the Global monsoon circulation and in turn on the Indian Summer Monsoon (ISM). The extended reconstruction of SSTs (ERSSTs) data has been used in this study. The data has been subject to analysis by statistical methods. Fourier analysis has been done to know periodicity. The climatology & trends in the Equatorial Pacific SSTs have been studied and results discussed. © 2015, India Meteorological Department. All Rights Reserved. Source

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