Monitoring Agricultural Drought in the Near East - Monitoring and Predicting Agricultural Drought: A Global Study - page 208

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M onitoring Agricultural Drought
in the Near East
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The countries of North Africa and West Asia, hereafter referred to as the
“Near East,” cover a large part of the world (more than 7,200,000 km 2 ).
This region is characterized by diverse but generally dry climates, in which
evaporation exceeds precipitation. The level of aridity is indicated by the
aridity index, the ratio of annual precipitation to annual potential evap-
otranspiration, calculated by the Penman method (UNESCO, 1979). The
degree of aridity is shown spatially in figure 16.1 and summarized per coun-
try in table 16.1. These data show that the region is characterized by humid,
subhumid, semiarid, and arid to hyperarid moisture regimes. In addition,
temperature regimes vary considerably, particularly due to the differences
in altitudes and, to a lesser extent, due to the oceanic/continental influ-
ences. For most of the region, the precipitation generally occurs during the
October-April period and thus is concentrated over the winter season.
Table 16.1 shows that, with more than 90% of the land area in hyper-
arid, arid, or semiarid moisture regimes, aridity is very significant in the
Near East. Turkey is better endowed with surface and groundwater re-
sources due to the orographic capture of Atlantic cyclonal precipitation,
but much of the interior is semiarid. If one excludes the hyperarid zones,
which cover the driest deserts and have no potential for agricultural use,
nearly 34% of the region, or about 2,460,000 km 2 , is dryland (i.e., the
area with arid or semiarid moisture regime). These are the areas with some
potential for either dryland farming (in semiarid zones) or for extensive
rangeland (in arid zones).
In the Near East countries, agriculture contributes about 10-20% to the
gross domestic product and is therefore a major pillar of their economies.
However, the indirect importance of agriculture is larger because it pro-
vides the primary goods that constitute the majority of merchandise ex-
ports and because of the relatively high number of people employed in
agriculture (table 16.2).

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