3.1.2. Spatio-temporal variations and trends in precipitation
The spatial distribution of annual and seasonal precipitation
(1901-2013) based on seasonal rainfall climatology of the region
(March-May (MAM); June-August (JJA); September-November (SON); and
December- February (DJF)) indicate considerable rainfall in the southern
and central sections of the basin in DJF and SON periods, respectively
(Fig. 3). Just for exploratory purposes, these seasonal distributions
are considered for the first and second halves of the century. There is
significant amount of rainfall all through the year in the Congo basin
except in the JJA period for the south and DJF for the north (Fig. 3).
In terms of direct water availability from rainfall, these sections of
the Congo basin, including the northern flank can be described as the
water tower of central Africa. The evidence of strong spatial
distribution of mean monthly and seasonal rainfall in the low elevation
areas of the Cuvette central and the in-terconnectedness of multiple
stream networks attest to the Congo basin being a freshwater rich
hydrological region (Figs. 3 and cf. Figs. 1a-b). Furthermore, the MLRA
and analysis of variance show that there is statistically significant
change in observed trends (F = 442. 7; p =
0. 000), annual (F = 8. 85; p = 0. 000),
and semi-annual (F = 4. 93; p = 0. 002)
amplitudes of rainfall during different climatological periods
(1901- 1930, 1931- 1960, 1961- 1990 and
1991- 2014) over the Congo basin (Figs. 4a-b). Consistent with
Fig. 3, the southern section of the Congo basin is characterized by
strong annual amplitudes in rainfall while towards the east, there is
considerable mean semi-annual amplitude of rainfall (Fig. 4a).