'IRAQ AND THE PERSIAN GULF' [‎123v] (251/862)

CHAPTER IV
CLIMATE, VEGETATION, AND FAUNA
CLIMATE
T he shores of the Persian Gulf The historical term used to describe the body of water between the Arabian Peninsula and Iran. , together with parts of Mesopotamia,
form in summer one of the hottest and most oppressive parts of the
world. In winter the country is colder than is normal for the latitude.
The topographical trend and height of the mountains to the north and
north-east, with the Anatolian and Persian plateaux beyond them,
the depression of the Persian Gulf The historical term used to describe the body of water between the Arabian Peninsula and Iran. to the south-east, the arid Arabian
peninsula to the south, the Hamad and the Mediterranean beyond the
Syrian mountains to the west—all these exert their influence on the
climate of Iraq. Thus the prevailing winds throughout the year are
northerly in origin, coming from the southward extension of the
Eurasian high-pressure system in winter, and drawn towards the
low-pressure system of northern India in summer; they become
north-westerly in Mesopotamia because that is the trend of the
Persian barrier; they are remarkably constant and dry in summer,
because they can gather no moisture except from the marshes in the
south; and they become hotter as they pass south-eastwards. They
are, however, interrupted in winter by depressions travelling eastwards
from the Mediterranean, and during the passage of these depressions
falls almost the only rain that the country receives.
There are three climatic regions: the western and southern deserts,
the Assyrian and Mesopotamian plains, and the mountains. Condi
tions in the deserts are much the same throughout except fora gradual
decrease of altitude eastwards, but the middle region is affected by
local topography and proximity to mountains, marsh, and sea; alti
tude is the chief factor in causing differences in the mountains.
Throughout the country there are two pronounced seasons, summer
and winter, the ‘hot weather’ and the ‘cold weather’. Spring and
autumn are very short. Summer begins in May and lasts until
October. The heat is intense, the sky cloudless, the atmosphere dry,
and rain extremely rare. The prevailing north-west wind, the Shamal,
is strong by day but lulls to a breeze or drops altogether at night;
though a hot wind, it brings relief because of its dryness; water, for
instance, may be kept cool in Persian filters or canvas bags by the high
rate of evaporation, and the pores of the human skin act in the same
way. At Baghdad the temperature rises above ioo° F. on almost