The effect of humidity on climate

Zaid Hakim Jiyad
Under the supervision of Lect. Dr. Ali Khazal Jawad

The factors affecting relative humidity in Iraq are divided into two sections, main factors:
1) Fixed local factors: There are many fixed factors, the most important of which are:
A. Water bodies, including rivers, artificial lakes, permanent and seasonal marshes, in addition to rainwater collected on clay soils in the winter and spring.
The weakness of local water bodies, which are determined by the Tigris and Euphrates rivers and their tributaries and the marshes with a local impact, in addition to the influence of the Arabian Gulf and the Mediterranean Sea, which appear clearly during the short winter and spring, and their impact decreases in the long hot season.
B. Vegetation, which includes:
A) The very limited natural vegetation cover in Iraq.
B) Agricultural production, which witnesses a large annual fluctuation, especially that which depends on rainfall.

2) Dynamic factors:
A. Low pressure systems are divided into two sections:
1. Frontal depressions: Frontal depressions move over the country, causing an increase in precipitation and thus an increase in air humidity. Although the rise in global temperatures will make Iraq a small share of these depressions due to their direction northward, as they advance from the Mediterranean Sea, their annual frequency over the country in the 1978/1979 season was about (39 depressions), which decreased to (24 depressions) in the 1988/1989 season. I also decreased the frequency of Mediterranean depressions merged with the Sudanese from (45 depressions) in the 1983/1984 season to (20 depressions) in the 1988/1989 season. This indicates a decrease in relative humidity in the future (72-56/1).
2. Thermal depressions: Thermal depressions contribute to raising temperatures, and most of them contribute to dry air, except for the Indian depression, whose average annual duration is (138.5 days), the Sudanese depression (35.3 days), the thermal island (10.9 days), and the Icelandic (10.2 days) and West Asia (0.8 days) and the subtropical (0.8 days) and the other (5.3 days) and the annual recurrence rate of all of them is (193 days) during the day and 185.3 days during the night (-37/639) that the Indian depression dominates during the summer in the south of the country due to the dominance of the hot dry northwesterly and westerly winds (poisons).
B. Highlands
Iraq is exposed to several types of highlands, including the subtropical high, whose annual recurrence rate is (33.5 days), the Siberian (85.1 days), and the European (9.3 days), so their annual recurrence rate is (127.9 days) and these work to repeat the northwesterly and westerly winds, which are characterized by their low temperature and dryness in winter, and their high temperature and severe dryness in summer (85/3).