Nepedia
Back to Discover
Advanced Reader
🌍

Subtropics

earth science Maturity 9-11 Next article →

The subtropics are essential geographical and climate zones located immediately north and south of the tropics. Geographically, these regions are part of the temperate zones in both the Northern and Southern Hemispheres. They typically cover the middle latitudes between approximately 35° and 40° north and south.

Subtropical
Subtropical

These zones are vital because they host a massive variety of ecosystems and agricultural systems. Because they sit between the extreme heat of the equator and the cold of the poles, they offer unique conditions for life. Many people find these regions ideal for living due to their generally pleasant weather patterns.

The weather in these zones is driven by a massive atmospheric process called the Hadley cell. Near the equator, the sun heats the Earth intensely. This heat causes large amounts of air to rise through a process called convection. As this air rises, it moves away from the equator at high altitudes. As the air travels toward the mid-latitudes, it begins to cool. This cooling makes the air denser, causing it to sink back toward the Earth's surface.

Earth Global Circulation - en
Earth Global Circulation - en

This sinking air creates a semi-permanent high-pressure area known as the subtropical ridge or subtropical anticyclone. This high pressure is the primary reason many of the world's deserts are located within the subtropics, often on the southwest sides of continents.

Climatologists use several different systems to classify these diverse environments. The most well-known is the Köppen climate classification, which uses temperature and precipitation to define regions. For example, the Köppen system identifies humid subtropical climates as Cfa or Cwa. Another method is the Trewartha climate classification. This system defines a subtropical region as one having at least eight months with a mean temperature above 10°C and at least one month below 3°C. Other scientists, like Carl Troll and Karlheinz Paffen, focused on plain and hilly lands. They divided the warm-temperate subtropical zone into seven smaller, specific areas.

Subtropical climates are generally divided into several distinct types based on moisture and temperature. The humid subtropical climate is characterized by hot, humid summers and mild winters. In these areas, rainfall is often concentrated during the warmest months. This occurs because subtropical high-pressure cells provide a sultry flow of tropical air with high dew points.

Fog in Tây Bắc
Fog in Tây Bắc

This type of climate is found in places like Southeast China and the southeastern United States.

Wetland Hong Kong
Wetland Hong Kong

Another type is the Mediterranean climate, often found on the western sides of continents. These regions, such as the Mediterranean Basin or Southern California, feature hot, dry summers and rainfall during the cooler months.

Fynbos, Lion's Head and trees from Table Mountain trail
Fynbos, Lion's Head and trees from Table Mountain trail

There are also more specialized variations like the subtropical highland climate. These are often found in mountainous areas within the subtropics or the tropics. These regions feature mild temperatures year-round and can experience four distinct seasons. Some highland areas have rainfall spread evenly through the year, while others show a strong monsoon influence with wet summers and dry winters. Additionally, some areas experience semi-desert or desert climates. These are characterized by an annual average temperature above 18°C and a lack of regular rainfall.

Acacia Negev
Acacia Negev

The mildness of the subtropics has a profound effect on the biology of the region. A concept known as the frost line serves as a dividing line between different plant groups. On the warmer side of this line, many plants are sensitive to low temperatures and can be killed by frost. On the colder temperate side, plants have evolved to survive long periods of low temperatures. Because subtropical winters are usually above freezing, many tropical plants can flourish here.

Liveoak,savannah
Liveoak,savannah

Common crops include citrus, mango, lychee, avocado, and pistachio. Farmers often prefer the subtropics because the cooler winters make it easier to control agricultural pests compared to the tropics.

Understanding the subtropics helps us see how global air circulation connects different parts of the planet. The movement of air in the Hadley cell explains why a desert in one hemisphere might share characteristics with a coastal region in another. It also explains why certain areas, like Japan, receive significant rainfall from typhoons. These tropical cyclones can contribute heavily to the annual water supply in subtropical zones. By studying these zones, we learn how heat, moisture, and pressure work together to shape the world's landscapes and support human civilization.

712 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (8)
File:Subtropical.png
Subtropical.png
File:East Battery Street Charleston Aug2010.jpg
East Battery Street Charleston Aug2010.jpg
File:Earth Global Circulation - en.svg
Earth Global Circulation - en.svg
File:Liveoak,savannah.png
Liveoak,savannah.png
File:Fog in Tây Bắc.jpg
Fog in Tây Bắc.jpg
File:Wetland Hong Kong.jpg
Wetland Hong Kong.jpg
File:Fynbos, Lion's Head and trees from Table Mountain trail.jpg
Fynbos, Lion's Head and trees from Table...
File:Acacia Negev.JPG
Acacia Negev.JPG
More to explore

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.