Climate zone B refers to Dry Climates, which are characterized by significantly low precipitation and high rates of evaporation.
These arid and semi-arid regions are found in specific geographical locations across the globe. They typically extend from 20° to 35° North and South of the equator, where subtropical high-pressure systems lead to clear skies and minimal rainfall. Additionally, Dry Climates are prevalent in large continental regions within the mid-latitudes, where they are often encircled by mountains. These mountain ranges create "rain shadow" effects, blocking moisture-laden air and contributing to the extreme dryness of these areas.
Characteristics of Dry Climates (Zone B)
Dry Climates are defined by a perpetual water deficit, where potential evaporation consistently exceeds precipitation. This leads to unique environmental conditions:- Aridity: These zones receive very little annual rainfall, often less than 250 mm (10 inches), making them the driest regions on Earth.
- Temperature Extremes: They frequently experience significant diurnal (day-night) and seasonal temperature variations. Days can be scorching hot, while nights can be surprisingly cold due to the lack of cloud cover to trap heat.
- Sparse Vegetation: The lack of water severely limits plant growth. Vegetation is typically scarce, consisting of highly specialized, drought-resistant plants like cacti, succulents, and some hardy shrubs, or is entirely absent in extreme deserts.
- High Evaporation: Strong winds and high temperatures cause any available moisture to evaporate rapidly from the ground and water bodies.
Geographical Distribution of Dry Climates
Dry Climates encompass a wide range of landscapes, from scorching hot deserts to cold deserts. Their distribution is influenced by global atmospheric circulation patterns and topographic features:- Subtropical Deserts: Located approximately between 20° and 35° latitudes in both hemispheres, these deserts are formed by descending dry air from the Hadley Cells. Examples include:
- The Sahara Desert (North Africa)
- The Arabian Desert (Middle East)
- The Atacama Desert (South America)
- Parts of the Australian Outback
- Mid-latitude Deserts: Found deep within continents, often shielded from oceanic moisture by mountain ranges (rain shadow effect). Examples include:
- The Gobi Desert (Central Asia)
- The Great Basin Desert (Western North America)
- The Patagonian Desert (South America)
While diverse in their temperature profiles, all areas classified under Climate Zone B share the fundamental characteristic of being moisture-deficient, supporting a fragile yet resilient ecosystem adapted to extreme dryness.
