Seasonal And Long Term Rainfall Trends In Calabar, Nigeria

Abstract

Rain fall trends all over the world with the attendant socio-economic effects have taken unprecedented dimensions in recent times. Trend studies of this atmospheric parameter will enable us examine the nature of variation
and possible causative agents. Both seasonal and long term trends of rain fall in Calabar between 1985 and 2003 have been examined. Monthly and annual rainfall totals, number of rain days and extreme rain fall indices were determined as secondary data and used for the analyses. SPSS statistical package was used to deseasolnalise the data and determine its trend. Both raw data and deseasonalised data were used to examine long term trends and both show some level of increase in rainfall of about 1.9mm and 300mm respectively. The results also show that rainfall has highly pronounced season. The seasonality of all the parameters namely total rainfall, total extreme rainfall, total number of rain days and number of extreme rain days were all similar, with a slight break in the month of August. This break introduces a week or more of drought which is essential for crop production, drying and storage of agricultural products and their by- products