The Republic of Azerbaijan is located at the northern extremity of the subtropical belt, the southeast of the Caucasus and the northwest of the Iranian plateau. The geographic location of the territory, the complexity of the terrain, the proximity of the Caspian Sea, the increased dose of solar radiation incident on the surface of the earth during the year, exposure to air currents of various origins and other factors have caused climatic diversity.
Surface structure. The territory of the Azerbaijan Republic, which is mostly mountainous, is surrounded by the Greater and Lesser Caucasus, Talish and Northern Iranian mountains. The Kura depression (its eastern part is the Kura-Araz lowland), located between the mountain system of the Greater and Lesser Caucasus, extending, extends to the Caspian Sea, washing the territory of the country from the east. The Greater Caucasus Mountains, located in the north of the country and stretching from the northwest to the southeast, protect most of the territory of the republic from the direct impact of cold air currents coming from the north. As a result, a subtropical climate is formed on the plains and foothills. The surrounding mountainous systems also exert a great influence on the air circulation processes. The diversity of the surface system contributes to the uneven distribution of various climatic features, the formation of vertical climatic zones.
Solar radiation. Plains and foothills of the Republic of Azerbaijan are characterized by excess sunlight. In the Kura-Araz lowland, Absheron peninsula, other flat and foothill areas, the annual number of hours of sunshine is 2200-2400 hours, the Priaraz plain of the Nakhchivan AR is 2,600-2,800 hours. In the mid-mountain zone, due to increased cloud cover, the number of hours of sunshine fluctuates between 1900 and 2200 hours. In the highlands this indicator again increases and in the territories over 3000 meters is 2200-2500 hours. The annual amount of total solar radiation in the Kura-Araz lowlands reaches 128-132 kcal / cm2. To the foothills it decreases (120-124 kcal / cm2) – approximately 500-600 meters above sea level. Then the amount of solar radiation again increases and in the highland zone of the Greater and Lesser Caucasus (above 3000 meters) is 140-150 kcal / cm2. In the Priaraz plain of the Nakhchivan AR, the annual amount of total solar radiation is 148-150 kcal / cm2, and in the high-mountain zone, increasing reaches 152-160 kcal / cm2. The annual amount of radiation balance in the plains and foothills of the country is 40-50 kcal / cm2 (in the Lankaran natural area – 50-60 kcal / cm2), in the highlands – 15-25 kcal / cm2.
Atmospheric circulation. In the territory of the Republic of Azerbaijan, the following cyclones influence the climate formation: Arctic (Kara and Scandinavian anticyclones), cold continental (Siberian anticyclone) and sea (Azores maximum), hot air currents of tropical latitudes (subtropical anticyclones and southern cyclones) Cyclone, as well as local atmospheric processes. As a result of the influence of the surface of the earth, these air currents invade the territory of the country from various directions. So, although the mountains of the Greater Caucasus, the Talysh and the Northern Iranian mountains do not actually interfere with the warm air flows penetrating the country from the south, but to some extent, they influence the change in their characteristics and the dynamics of atmospheric processes.