Large volumes of air in the troposphere, which have more or less the same properties, are called. The air mass covers an area of thousands and millions of square kilometers, extending upwards for several kilometers and even to the border of the troposphere. It is characterized by a general direction of movement, but inside this volume of air it can be different. Properties (temperature, dust content or transparency) the air mass acquires, in contact with the underlying surface, over which it is formed. Moving over a surface with different properties, it heats up or cools down, moistens or becomes drier and gradually turns into another air mass (transforms).
The Mediterranean zone is located in the regions located to the east of the peninsula. They are characterized by a mild and dry climate, with mild winters and hot summers. Most of the precipitation received comes from precipitation generated in the Mediterranean, which is often not very active. An important climatic phenomenon in these regions is the cold dip, which usually occurs in autumn, when the presence of a mass of cold air in height coincides with the polar origin, and the Mediterranean temperature is still high.
In this case, when the rising masses of warm and humid air meet these pockets in cold air, they condense very quickly and cause heavy rainfall and violence. In the Mediterranean zone, a certain gradient can be established by increasing aridity conditions as it descends to the south, appearing in the semi-arid zones of the southeast zone.
The development of and is associated with atmospheric fronts.
Cyclone- vortex air movement with low pressure in the center and air movement against, from the periphery to the center. The passage of cyclones is accompanied by cloudy, rainy weather. In summer, they are associated with a slight decrease in temperature, in winter, an increase in it.
Anticyclone- vortex movement of air clockwise from the center to the periphery, with high pressure in the center. With the advent of the anticyclone, calm, clear weather sets in with high temperatures (summer) and very low temperatures (winter).
Finally, consideration should be given to island climates associated with the peninsula. Balearic Islands will present a Mediterranean climate with milder conditions than present on the continent, caused by their state of the islands, in which the Mediterranean moderates the temperatures and increases the humidity of the islands.
The climate of the Canary archipelago is different from that of the peninsula. Being located at lower latitudes, the influence of ocean storms is much lower, and the presence of tropical anticyclones is almost constant. This fact should lead to the fact that the islands will have a dry, deserted tropical climate. In fact, it is a climate that presents islands with lesser relief, while south of those with greater relief. However, north of most famous islands strongly influenced by the trade winds with a northeasterly component, which provide high humidity for these insular slopes, causing the appearance of a humid tropical climate.
Transitional zones are characterized by weather determined by the air mass that prevails over this territory during a given period of the year.
This table provides a generalized description of both archipelagos. Precipitation corresponding to Canary Islands, do not arise due to its large inhomogeneity. From southeast to northwest in the southern hemisphere. That is, high tropical pressures at low equatorial pressures. They meet at the equator in the "convergence zone" where they form air currents that increase in strength and give rise to important nebulae. as well as heavy rainfall. Due to the light winds and many periods of calm that prevail in these regions, navigators speak of zones of calm calm.
Subtropical climatic zones - geographic zones Northern and Southern Hemispheres the globe stretching between tropical and temperate zones. For the area located in this belt, the alternation of temperate and tropical climatic regimes is characteristic. This is due to the seasonal rhythms of the general circulation of atmospheric air: in summer time subtropical belts are under the influence of the trade wind climatic regime, in winter - under the influence of cyclonic circulation of moderate air masses. The exception is the eastern outskirts, where summer monsoon precipitation is observed.
In the Aliza zone corresponds in each hemisphere from 30 to 35 degrees of latitude a zone of subtropical high pressure, where good weather prevails. There the winds explode weakly, the precipitation is not very important, and Atmosphere pressure, high, markedly constant. These subtropical zones high pressure are also part of the global wind systems.
Frequent high pressures in the central North Atlantic centered south or west of the Azores also belong to the subtropical high pressure belt of the northern hemisphere. Stunning weather conditions are especially important in spring and autumn. These high pressures bring good weather to Europe and are often the center of precipitation for western meteorological situations typical of Europe. Planetary wind systems move according to the seasons, northward in summer and south in winter, 10° maximum, according to the Sun's position, but with a delay of several months.
During the summer average temperature air is more than 20 °С, in winter - more than 4 °С. With the penetration of polar air masses, there is a high probability of frosts and slight frosts (up to -10 °С). Above land in the subtropical zone precipitation and their regime varies considerably from the coastal areas of the ocean to the inland ones. This, in combination with an increase in the continentality of the climate in the same direction, causes significant landscape differences in the characteristics of natural zones.
Thus, the northernmost latitudes are reached in September, and in the southern latitudes in March, these movements are of great importance for the weather in the tropics, they determine the rainy season and the formation of cyclones. tropical. Another important system is periodic winds, commonly referred to as monsoons. It is the monsoon winds that determine the weather in the south and southeast of Asia, and in summer the air masses strike from the colder sea on the warmer continent, giving in Winter the air masses are taken away from the cold continent to more warm seas, resulting in a dry, slightly cloudy climate.
On the territory of each of the continents in the subtropical zones, three main regions are clearly distinguished: the western oceanic, or Mediterranean, with high humidity in winter; continental with insufficient air humidity year-round; eastern oceanic, or monsoonal, with high air humidity in summer.
Natural zones of the subtropical belt
In the western oceanic region, the so-called semi-dry subtropics, there is a zone of hard-leaved shrubs and forests on brown soils. In the Northern Hemisphere, after the zone of hard-leaved forests and shrubs, the zones of subtropical steppes on gray-brown soils follow to the southeast. To the east, there are zones of subtropical semi-deserts and deserts of the continental region on gray-brown soils and gray soils. These are dry subtropics.
In middle latitudes, i.e. in most European countries, there is a constant exchange of air masses from subtropical regions to polar regions, which is very typical. The polar corridor of low pressure, which is about 60 degrees latitude, extends into the northern hemisphere of Scotland, south of Norway and Sweden, and into the bay. from Bothnia; it is rather narrow and borrowed by non-tropical cyclones.
The wind of the globe is subject to general phenomena, which are mainly the difference between the superheating of the Earth and the oceans by the Sun and the temperature gradient, according to the difference in insolation, from the equator to the poles. Above the subtropical high-pressure belt, there is an area of jet streams flowing from west to east. Jet streams are an expression of tremendous turbulence in the troposphere due to parallel wind forces that reinforce or oppose each other.
V southern hemisphere in the continental regions of the subtropics, there is a zone of subtropical steppes on gray-brown soils. In the eastern regions there are humid subtropics with evergreen broad-leaved forests, and in higher latitudes - deciduous broad-leaved forests with an admixture of evergreen woody plant species on red soils, yellow soils and yellow-brown soils. In mountainous areas, the subtropical belt corresponds to forest-meadow (in humid areas) and forest-steppe (in dry areas) levels of altitudinal zonation.
Folding winds and tornadoes. Apart from large wind systems, all kinds of limited airflows are related to local conditions. We have already spoken of the winds of the earth and the sea, as well as the winds due to storms. There are such winds all over the world, but especially in regions where landforms force air currents to rise or fall. The latter brings cold air to the Mediterranean regions. Another typical wind is the bojra, a dry and rather cold wind that blows from the disordered heights of the Dalmatian and Albanian coasts towards the sea and accompanies various weather conditions.
On the territory of the CIS countries there is a section along the upper border subtropical belt, because the nature here does not correspond to the typical for the subtropics. Subtropics occupy Black Sea coast caucasus, South coast Crimea, Colchis, Kura-Araks and Lenkoran lowlands, the Alazani valley and the southern outskirts of the deserts of Central Asia.
Thus, in winter it is born under high pressure in the Balkan Peninsula and in Eastern Europe: the weather is good, dry and cold, sometimes for several weeks. Bora also explodes when the Adriatic is covered in low pressure and the Balkan Peninsula is under high pressure. The cyclonic bora not only brings a storm, but sometimes also heavy rainfall, however, only for one day, if not for several hours. Although the bora is a wind, it is cold because it comes down from the mountains and it does not heat up. The cold air entering the Adriatic, where the air is always warmer, makes the latter cool, humid and thus manifests itself in a typical phenomenon from the very beginning, the formation clouds in the Adriatic, where the air is always warmer. mountains mountains.
Due economic activity In the subtropics, forests are often replaced by plantation and field landscapes. In the fauna, there is a cohabitation of species of temperate and tropical belts. Ocean waters in the subtropics are characterized by relatively high temperature(15-16 °С) and high salinity of water. As a result of weak vertical mixing ocean waters the concentration of oxygen and plankton in them decreases. This is due to the small number of commercial fish.
The mistral is a wind along the coast of southeastern France. Cold and dry, it blows from the north into the Rhine valley between Avignon and Marseille. This is due to depression in the Mediterranean, hot and anticyclone in the Cevennes and Elpesna, whose atmosphere is cold and dry in winter. Low pressure sucks in air, the Rhine Valley acts like a ravine. throttling, which further amplifies the wind.
Sirocco is the wind down the coast North Africa, hot and dry, from the south. This is due to a depression in the Mediterranean that sucks in the Atlas air. When it blows from the Sahara, it often carries sand with it, it reaches even Central Europe. In the western Mediterranean, it generates swirling bursts. In the eastern Mediterranean, a similar but non-folding wind is generated by a low pressure zone from the west.
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