f. Monsoon climates.
The monsoons have a strong influence on plant growth of all types because of the effect they have on the seasonal occurrence of the rainy season. me basic causes of monsoons are poorly understood, but they can be predicted to some extent. They have considerable variability in the dates of beginning and their duration. The name "Monsoon" is Arabic, and was originally applied to the seasonal winds of the Arabian (Persian, Sea, that blow about six months from the southwest. The winds are caused by differences of annual temperature trends over land. Temperature changes are large over land, but small over oceans. The monsoon blows from cooler to warmer regions; from sea toward land in summer (bringing rains), and from land toward the sea in winter (without rains). Atmospheric pressure is relatively high in cooler regions and lower in warm regions, permitting air-mass movement to take place.
The monsoon type of air movement by seasons occurs throughout the tropics, and is perhaps better known in the Indian subcontinent than elsewhere. However, monsoon type climates are widespread in the tropics and subtropics. Monsoon winds blowing from oceans toward and across land masses of Africa and South America are important factors in producing the rainy season of those tropical climates; and the reverse flow of air masses from land toward the ocean causes the dry seasons. The periodicity of rainfall in the tropics is well established by rainfall records that are now available in virtually all developing countries.