Earth Science: Subtropical Climates
Subtropical areas can be found in a belt between the tropics and 45° north or south latitude. These areas are the climatic transition between tropical and temperate latitudes. The Mediterranean climate is a specific climate type located within the subtropical zone.
The subtropics are defined as a climatic zone with high temperatures in the summer and mild temperatures in the winter caused by a seasonal shift of the subtropical high pressure areas. Temperatures and the amount of precipitation depend less on geographical latitude than on where the area is located on the corresponding land-mass. Dry subtropical regions with large deserts such as the Sahara in Africa or the deserts of Australia are located at the center of these continents.
Here, precipitation of less than four inches (100 mm) per year is not unusual. Even shrubs and thorn scrub will only grow in certain areas with favorable conditions. The eastern parts of these continents experience monsoons during the summer carrying heavy rainfall. This is where the subtropical moist forests are found. The western parts of these continents, however, have a subtropical climate with dry seasons in the summer and rainy seasons in the winter.
Mediterranean climate
The Mediterranean climate zone is located between 32° to 45° north and 28° to 38° south latitudes. As the name indicates, the Mediterranean climate is prevalent in the Mediterranean regions, but it also exists on the coast of California, along a coastal strip of Chile, in the Cape Town area, and on the southwest coast of Australia. All these regions experience rainy winter seasons, sometimes with frost, yet the average temperatures of the coldest months are above 41 °F (5°C).
Average summer temperatures vary between 73°F (23°C) in Europe and 82°F (28°C) in Australia. The dry summer season with little or no rain lasts about four to six months. The main growth period for plants is there- fore during the spring. Sclerophyll is the typical vegetation of this climate zone. Its plants have small hard leaves with a coriaceous surface that protect the plant from water loss caused by evaporation.
The natural vegetation in the Mediterranean mostly consists of evergreen oak forests, with the prevalent holm oak. Many Mediterranean forests have deteriorated, however, into shrubland communities with Mediterranean heaths. This type of plant community occurs in different parts of the world and has different local names: Italian macchia, French garrigues, the fynbos of Cape Town, or the California chaparral. In Mediterranean Australia, the predominant plant of the sclerophyll forests is the eucalyptus and in Chile it is the litre tree.
BASICS
CLIMATE CLASSIFICATIONS There are different methods for the classification of the climates on Earth. One of the most well-known methods was developed by the geographer Wladimir Peter Kdppen (1846-1940).
The Koppen climate classification method is based on the relationship between temperature, precipitation, and vegetation. Here, individual climate zones and types are separated by the mathematical mean of distinct threshold values.
The so-called effective classification was published in 1923 and has been reworked several times since.