期刊名称：Research Journal of Environmental and Earth Sciences
印刷版ISSN：2041-0484
电子版ISSN：2041-0492
出版年度：2010
卷号：2
期号：2
页码：89-96
出版社：Maxwell Science Publications
摘要：Rainfall data for 35 years (1974-2008) for Kafanchan located within latitude 9º 3'N and longitude 8º 17' E were used in this analysis in order to detect the recent trends in the rainfall regime of the area. The calculated Relative Seasonality Index for the area revealed that rainfall regime is markedly seasonal with a long drier season. In order to identify trends, the rainfall series was divided into 10-year overlapping sub-periods 1974-1983, 1979-1988 through 1999-2008 and the Cramer's test was then used to compare the means of the sub-period with the mean of the whole record period. The results of the test revealed that the sub-period 1974-1983 and 1999-2008 for the months of June and October respectively were significantly drier. The results of the Standardized Anomaly Index revealed that rainfall yield is declining in the study area. The 5-year running mean shows that the declining yield of the annual rainfall started from 1990 to date. The results of the linear trend lines further revealed that the decline in the annual rainfall yield is predominantly as a result of the substantial decline in July, September, and October rainfall, which are the critical months for agricultural production in the area. It is recommended that agricultural planning and government policies in the area should be based on recent rainfall trends.
