Variations and Trends in Annual Rainfall Amounts and the Onset of the Rainy Season for Kano for 87 Yaers (1916-2002)

Ojonigu Ati, Sedu Muhammed, Maeyam Ati
2008 Journal of Applied Sciences Research   unpublished
Rainfall data for 1916-2002 were used and onset dates were calculated based on a hybrid method by Ati, et al. The 10-year running mean was used to test for trends in the series. In order to [1 ] further identify the long-term temporal variance structure in the rainfall and its series, they were subdivided into decadal periods (1920-1929, 1930-1939...1990-1999). Their means, standard deviations and coefficients of variation were compared. Annual rainfall totals in Kano was decreasing
more » ... since the 1960s but the last decade especially the late 1990s have been witnessing increasing annual rainfall totals. M ost studies dealing with data terminating before the mid-1990s agree with the conclusion of decreasing annual totals from the 1960s. Later studies agree with the increasing annual rainfall from the [6 ] mid-1990s. There is no clear pattern shown for the trend in onset dates. If the present upward trend in annual rainfall totals continues, a statistically significant shift in the onset dates may be expected to occur.