Indian Journal of Soil Conservation
Year : 2008, Volume : 36, Issue : 3
First page : ( 125) Last page : ( 128)
Print ISSN : 0970-3349.

Rainfall characteristics of Sagar island in Sundarban, West Bengal

Chakraborty P.B., Mandai A.P.N.

Bidhan Chandra Krishi Viswavidyalaya, Regional Research Station (Coastal Saline Zone), Kakdwip, 743347, WB..

Received:  February,  2008; Revised:  December,  2008; Accepted:  December,  2008.

Abstract

Twelve years' (1990–2001) historical rainfall data of Sagar Island revealed that the total mean annual rainfall is 1924.19 mm and 50% of the years received more than the mean rainfall. Such variation had significant positive correlation (r = 0.924**) between rainfall and rainy days. However, maximum (148.23 mm) rain occurred in 29^th week followed by 36^th week. The rainfall was found to be bi-modal in nature having two peaks usually at 29^th and 37^th weeks, respectively. With years, shift in the peaks has been observed. In 41.7% of the years the first peak shifted to the month of July and/or August instead of June, whereas, the second peak shifted to the month of September in 57% of the years. Such shift was markedly observed after 1995 indicating a considerable change in climatic behaviour. However, the dependable rainfall at 76.90 probability is expected to occur in every year during 24th to 29^th weeks. The monthly dependable rainfall is expected to occur in every year during the month of May to October with major concentration during June to September.

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Key words

Annual rainfall, Bi-modal, Peak rainfall, Probability, Weekly rainfall.

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