RESUMENLos Himalayas desempeñan un papel importante en el clima y el tiempo meteorológico de la India, y controlan tanto las perturbaciones del oeste (PO) durante el invierno como el monzón del suroeste durante el verano. En los meses de invierno (diciembre a marzo), los vientos del oeste asociados con PO causan precipitaciones, en ocasiones asociadas a fuertes nevadas y extensas avalanchas sobre Himachal Pradesh. Por tal motivo, el presente estudio analiza la variabilidad temporal de la frecuencia de PO y de diversos índices de precipitación (como número de días húmedos y lluviosos, días con precipitación fuerte y muy fuerte, e intensidad de la precipitación de 1977 a 2007) en Himachal Pradesh durante el invierno. También se analizan las caracterís-ticas sinópticas asociadas con PO intensas que provocaron fuertes precipitaciones sobre la región durante el Himachal Pradesh ocurre sobre todo como resultado de las PO, tanto la precipitación total como los días con precipitación fuerte y muy fuerte han disminuido en la región. El análisis también muestra una disminución de alrededor de 25% en los días de precipitación fuerte y de 13% en la precipitación invernal total sobre Himachal Pradesh respecto de su media respectiva (de 1977 a 2007). ABSTRACTThe Himalayas have an important role in Indian weather and climate, since they control the western disturbances (WDs) during winter and the southwest monsoon during summer. During the winter months (December to March), westerly winds associated with WDs cause precipitation, sometimes along with heavy snowfall, extensive avalanches, etc., over Himachal Pradesh. Therefore, this study examined the temporal variability in the winter months frequency of WDs and various precipitation indices like wet days, rainy days, rather heavy and heavy precipitation days, and precipitation intensity during 1977 to 2007 over Himachal Pradesh. The study also examined synoptic features associated with intense WDs that caused heavy precipitation over the region trend in the frequency of WDs over this region. Since winter precipitation in Himachal Pradesh mainly occurs due to WDs, total winter precipitation and frequency of rather heavy and heavy precipitation days have decreased over the region. The analysis also shows a decrease of about 25% in heavy precipitation days and of 13% in total winter precipitation from their respective mean (from 1977 to 2007) over Himachal Pradesh.

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Globally water resource management is becoming a priority for every Government. This is due to tremendous increase in population growth,urbanization, modern life style, increase in agricultural activities, industrialization etc. which is increasing the water demand day by day. This paper focuses on design storms studiesusing return period analysis technique (Isopluvial analysis) based on 129 well distributedSelf Recording Raingauge (SRRG) stations in the various climatic zones of India. The extreme rainfall values are taken for preparation of Isopluvial maps for return period of 2-year, 5- year, 10-year, 25-year, 50-year and 100-year at1-hour, 3-hour, 6-hour, 12-hour and 24-hour duration. Further, station wise Intensity Duration Frequency (IDF) curves are also prepared for 27 stations of the country. The Gumble distribution technique for extreme rainfall series is used for this study. Isopluvial maps & IDF curves are found very useful for Design engineers, hydrologists and hydraulic-consultants for the purpose of planning & designing of water resources related projects in the country forthe construction of any drainage network system, metro, road ways etc.and also, to some extend for the estimation of availability of water.  

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A diagnostic study has been carried out to analyse and understand the causes of unusual rainfall activity over Jammu & Kashmir (J&K) State during 2nd to 5th September, 2014. The careful examination of available historical rainfall data of India Meteorological Department (IMD) network reveals that many stations in the region received ever-highest 24, 48 & 72 hours cumulative rainfall during first week of September in 2014, breaking all previous records. In result, there was flooding in most parts of the State, which has caused loss of human lives and huge loss of property. The synoptic interpretation of this unusual event carried out in the study confirms very favourable meteorological conditions, as there was a western disturbance (WD) in form of cyclonic circulation/trough in mid-tropospheric level, which remained practically stationary over north Pakistan and adjoining Jammu & Kashmir from 2nd to 5th September, 2014 and its interaction with a monsoon Low-Pressure Area (LPA) over northwest & adjoining central India during the same period.  In addition, jet maxima of the order 60-80 knots and high moisture advection from the Bay of Bengal as well as from Arabian Sea over the region were also responsible for this unusual rainfall.