Environmental Engineering Reference
In-Depth Information
Figure 5.4
Mean monthly precipitation at Singapore, in the
equatorial trough zone.
Figure 5.5
Mean monthly precipitation at Las Vegas,
Nevada, in an arid zone.
(Figure 5.5). Even within the same pressure belt, some seasonal pattern may be evident.
In the mid-latitudes, where rainfall is associated with the activity of the rainbearing
cyclones, the winter and autumn are relatively wet, for it is at those periods that the
westerlies bring the most frequent and intense storms.
In the tropics and subtropics, where convectional rainfall is more important,
precipitation tends to be more abundant during the summer months (Figure 5.6). The
magnitude of these seasonal variations is even more marked in the monsoonal areas of
the world, where the year can be subdivided into a wet and a dry season. At
