"العراق والخليج الفارسي" [و‎‎١‎٣‎٢] (٨٦٢/٢٦٨)

CLIMATE
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becomes marked about three hours after sunrise; at its worst it may
reduce visibility to a few hundred yards, but its worst effects are
mitigated by ascending a very few feet above ground-level. In the
early days of the War of 1914-1918 artillery observation was carried
out from ships; later, batteries were supplied with observation
ladders or extensions to limber-poles (photos. 73, 74). There is, of
course, no difficulty from mirage in observation from aircraft.
Fog is rare in Iraq, occurring on the average 6 days a year at
Shuaiba, 8 or 9 days at Baghdad, 4 days in the western desert at
Rutba, and 14 days at Mosul. It is commonest in December and
January.
Shuaiba has also recorded visibility over a period of nine years at
5 a.m., that is, before mirage becomes effective. Most dust-storms
also occur later in the day. The figures probably include fog, mist,
and dust-haze. The average number of days on which visibility has
fallen there below 2 nautical miles is only 11, fairly evenly distributed
throughout the year.
Sunshine and Cloud (Table IX)
The hours of sunshine are very high. There are records covering
six years between 1922 and 1936 for Mosul, where the average number
of hours per day throughout the year is 8-9. June, July, and August
all have daily means of over 12 hours, and are practically cloudless.
More recently sunshine records have been taken at both Mosul
and Baghdad, where for the year 1940 they are given as percentages
of the maximum amount possible. These show higher figures for
Baghdad than for Mosul in every month.
All five stations record the amount of cloud throughout the year.
The average cloud-cover for the winter is perhaps rather higher than
would be expected for the small amount of precipitation, but
otherwise there are no special points to notice.
VEGETATION
Iraq, within its present political boundaries, includes three main
regions: {a) the ancient Mesopotamia lying between the rivers Tigris
and Euphrates; (b) a mountainous area to the north-east, forming
part of the Kurdistan ranges; (c) a part of the Syrian desert, an arid
inhospitable region west and south of the Euphrates.
The climate is semi-arid, with a rainfall which, though moderately
plentiful in the northern and north-eastern districts, especially in the