Cosmic factors (the source of solar energy: variation in solar activity) ;
Planetary factors (distribution of this energy according to the sphericity of the Earth, its movements; the state, as well as the dynamism of the atmosphere);
The geographical factors (the land, the link between the atmosphere and the oceans, the reliefs, the vegetation, the volcanoes, the human installations);
As we have just seen above: the Earth’s climate system is composed of three groups of factors. The engine of this system is the Sun, which is our own energy source. These elements cause air and ocean circulation and control the evaporation and precipitation processes, which are part of the water cycle.
Many factors, both natural and man-made, determine the Earth’s climate. Climate depends on the redistribution of the Sun’s energy along atmospheric and oceanic currents.
Climates depend largely on latitude, longitude and altitude. They are also conditioned by the proximity of large bodies of water, such as oceans or inland seas. In general, our climate is defined by the complex interaction of all the major elements: the Sun, the land, the sea, the air, the Earth’s ice cap, wildlife and other life forms.
Many climatic phenomena disturb the climate. Example: El Niño or La Niña, the N.A.O… and the position of the Earth in relation to the Sun, which is very important
On Earth climates are classified according to different parameters (humidity, temperature, sunshine, wind speed…). These parameters vary according to the geography so the altitude, the latitude, the oceans in the surroundings,… as it influences the climate.
THE TROPICAL CLIMATE
The tropical climate is a climate found between the Tropic of Cancer and Capricorn, therefore between 25° South and North latitude. Throughout the year the average monthly temperature does not go below 18°C.
There are generally two types of tropical climates:
The humid tropical climate which is characterized by two seasons:
the wet season with high temperatures and very heavy rainfall (monsoon) but with a volume that decreases when moving away from the equator;
the dry season with lower temperatures and almost no rainfall which lasts longer the further away from the equator one gets (7 to 10 months).
The equatorial climate is characterized by a single season with frequent and significant rainfall whose maximum intensity occurs at the equinoxes (March and September). Temperatures are warm with an average of about 27°C. The atmospheric pressure is always low.
THE DRY OR ARID CLIMATE
The dry climate is characterized by a very high stability of the atmosphere, which means that precipitation is very low or absent. This climate is found between 10 and 35° North and South latitude.
There are two types of dry climates:
The arid climate characteristic of desert regions such as the Sahara, the Australian desert, the Arabian Peninsula… All year round, temperatures are high during the day but low at night, with occasional frosts, resulting in very large temperature differences between day and night (between 20 and 30° C and sometimes over 50° C). The annual rainfall is lower than the evaporation.
The semi-arid climate or steppe climate is characterized by a dry season most of the time and by a wet season. Rainfall is low with an annual average of between 250 and 500 mm which are unevenly distributed throughout the year.
THE TEMPERATE CLIMATE
The temperate climate is located between the parallels 30° and 50° of latitude in the northern and southern hemispheres and is characterized by two seasons, the cold season (winter) and the hot season (summer).
There are several types of temperate climates:
The oceanic climate characteristic of the western coasts of the continents (Northwestern United States, the British Isles, on the Atlantic coast of France, around the North Sea and the English Channel, on the Atlantic coastline Northwestern Morocco). The climate is influenced by the proximity of the oceans to the west of the continent which gives cool summers and mild, wet winters.
The humid subtropical or Chinese climate is characterized by hot and humid summers and cool winters. This climate is found on the eastern side of the continents between 30° and 50° latitude (between the east and southeast of the USA, South America, Asia and Australia).
The Mediterranean climate is characterized by hot, dry summers, mild, wet winters and heavy rainfall in spring and fall. This climate is found around the Mediterranean Sea, but other regions on Earth have the same climatic conditions such as the coastal areas of California, South Africa and the southern regions of Australia.
CONTINENTAL CLIMATE
The continental climate is located in the middle latitudes in areas far from the coast.
There are two types of continental climate:
The humid continental climate is characterized by hot summers and cold winters. Seasonal temperature differences are significant, ranging from 15 to 22°C, but can rise to 33°C. The further away the area is from the oceans, the greater the variation in temperature between summer and winter.
The subarctic climate is characterized by mild summers where temperatures can still exceed 30°C but this season is short and very harsh winters where temperatures can drop to -40°C. This climate is found between 50° to 70° North in most of Asia and in the North of North America.
POLAR CLIMATE
The polar climate is located at high latitudes.
We distinguish two types of polar climate:
The polar climate of the ice caps is characterized by cold temperatures all year round, which drop very low in winter and are always below -40°C during this season. The winds are strong and regular. In summer the average temperature is negative. The precipitations are weak and fall only in snow storms. The ground never thaws and nothing grows there.
The tundra is a climate found at the border of the ice cap in the Northern Hemisphere. Winters are long and cold, with an average temperature of about -28°C and with an often violent wind (blizzard). Summers are short and cool.
MOUNTAIN CLIMATE
The mountain climate depends on the mountainous regions. Temperatures, air pressure and air density decrease with altitude (about 0.5°C to 1°C every 100m). Winters are cold and summers are cool and humid. Precipitation is more important with altitude.
