A study of the relationship between the previous barometric Pressure and relative humidity on the daily rainfall at Coimbatore

Abstract

Correlations between rainfall of 10 cents and above and barometric pressure and relative humidity were worked out based on fifteen years data (1949 to 1963). No significant correlations were noticed during the Dry Weather period (January and February) and the Southwest Monsoon period (June to September).

During the Hot Weather period (March to May) barometric pressure on two days and three days prior to the day of actual rainfall had a positive influence on rainfall at 5 per cent level. If the rain is of the order of 50 cents, the fall in barometric pressure is appreciable. The same was noticeable in the case of relative humidity three days previous to the rainfall. During the Northeast Monsoon period the significance of relative humidity recorded on three and two days before rainfall is at 5 per cent level, while on the previous day the level of significance is at 1 per cent level.