The density of reporting network necessary for proper appraisal of the occurrence of rainfall in small areas in different localities in India in various seasons

Abstract

A study has been made of the minimum density of network of raingauge stations necessary for a proper appraisal of the character of rainfall in a given small area. Apart from the statistical value of the results obtained, this study has thrown some useful light in regard to our criteria for the assessment of rainfall forecasts for small areas such as those included in the Farmers' Weather Bulletins. Some of the findings of the study are of particular interest. For example, while one would conclude, on the basis of data of Calcutta alone that the liability of the area round about the station to get rain of 10 cents or more during the premonsoon season is only 11 for every 100 days, the analysis based on data of all raingauge stations within 50 miles round about Calcutta shows that on as many as 53 per cent days one or more stations in that area is likely to have rain of 10 cents or more. Similar findings, as have been obtained for other areas and in other seasons, are of value inconnection with the districtwise forecasts that are being issued for the use of farmers.