Semi-arid climate

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A semi-arid climate or steppe climate is the climate of a region that receives precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-arid climates, depending on variables such as temperature, and they give rise to different biomes.

Climate Statistics of weather conditions in a given region over long periods

Climate is the statistics of weather over long periods of time. It is measured by assessing the patterns of variation in temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate differs from weather, in that weather only describes the short-term conditions of these variables in a given region.

Desert climate type of climate

The desert climate, is a climate in which there is an excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in desert climates hold little moisture and evaporate the little rainfall they receive. Covering 14.2% of earth's land area, hot deserts may be the most common type of climate on earth.

Biome Distinct biological communities that have formed in response to a shared physical climate

A biome is a community of plants and animals that have common characteristics for the environment they exist in. They can be found over a range of continents. Biomes are distinct biological communities that have formed in response to a shared physical climate. "Biome" is a broader term than "habitat"; any biome can comprise a variety of habitats.

Contents

Regions with semi-arid climates
BSh
BSk Koppen World Map BSh BSk.png
Regions with semi-arid climates
   BSh
   BSk

Defining attributes of semi-arid climates

A more precise definition is given by the Köppen climate classification, which treats steppe climates (BSk and BSh) as intermediates between desert climates (BW) and humid climates in ecological characteristics and agricultural potential. Semi-arid climates tend to support short or scrubby vegetation and are usually dominated by either grasses or shrubs.

Köppen climate classification widely used climate classification system

The Köppen climate classification is one of the most widely used climate classification systems. It was first published by the Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notably in 1918 and 1936. Later, the climatologist Rudolf Geiger introduced some changes to the classification system, which is thus sometimes called the Köppen–Geiger climate classification system.

Steppe ecoregion in the montane grasslands and shrublands

In physical geography, a steppe is an ecoregion, in the montane grasslands and shrublands and temperate grasslands, savannas and shrublands biomes, characterized by grassland plains without trees apart from those near rivers and lakes. In South Africa, they are referred to as veld. The prairie of North America is an example of a steppe, though it is not usually called such. A steppe may be semi-arid or covered with grass or shrubs or both, depending on the season and latitude. The term is also used to denote the climate encountered in regions too dry to support a forest but not dry enough to be a desert. The soil is typically of chernozem type.

Shrub type of plant

A shrub or bush is a small- to medium-sized woody plant. Unlike herbs, shrubs have persistent woody stems above the ground. They are distinguished from trees by their multiple stems and shorter height, and are usually under 6 m (20 ft) tall. Plants of many species may grow either into shrubs or trees, depending on their growing conditions. Small, low shrubs, generally less than 2 m (6.6 ft) tall, such as lavender, periwinkle and most small garden varieties of rose, are often termed "subshrubs".

Sahel region of Mali Les Falaises de Bandiagara.jpg
Sahel region of Mali

To determine if a location has a semi-arid climate, the precipitation threshold must first be determined. Finding the precipitation threshold (in millimeters) involves first multiplying the average annual temperature in °C by 20, then adding 280 if 70% or more of the total precipitation is in the high-sun half of the year (April through September in the Northern temperate zone, or October through March in the Southern), or 140 if 30%70% of the total precipitation is received during the applicable period, or 0 if less than 30% of the total precipitation is so received. If the area's annual precipitation is less than the threshold but more than half the threshold, it is classified as a BS (steppe climate). [1]

Furthermore, to delineate "hot semi-arid climates" from "cold semi-arid climates", there are three widely used isotherms: Either a mean annual temperature of 18°C, or a mean temperature of 0°C or −3°C in the coldest month, so that a location with a "BS" type climate with the appropriate temperature above whichever isotherm is being used is classified as "hot semi-arid" (BSh), and a location with the appropriate temperature below the given isotherm is classified as "cold semi-arid" (BSk).

Hot semi-arid climates

Regions with hot semi-arid climates Koppen World Map BSh.png
Regions with hot semi-arid climates

Hot semi-arid climates (type "BSh") tend to be located in the 20s and 30s latitudes of the (tropics and subtropics), typically in proximity to regions with a tropical savanna or a humid subtropical climate. These climates tend to have hot, sometimes extremely hot, summers and warm to cool winters, with some to minimal precipitation. Hot semi-arid climates are most commonly found around the fringes of subtropical deserts. Hot semi-arid climates are most commonly found in Africa, Australia and South Asia. In Australia, a large portion of the Outback surrounding the central desert regions lies within the hot semi-arid climate region. [2] [ clarification needed ] In South Asia, both India and sections of Pakistan experiences the seasonal effects of monsoons and feature short but well-defined wet seasons, but is not sufficiently wet overall to qualify as a tropical savanna climate. Hot semi-arid climates can also be found in Europe (primarily in Southeast Spain [3] [4] ), parts of North America, such as in Mexico, and areas of the Southwestern United States, and sections of South America such as the sertão , the Gran Chaco, and on the poleward side of the arid deserts, where they typically feature a Mediterranean precipitation pattern, with generally rainless summers and wetter winters.

Tropics region of the Earth surrounding the Equator

The tropics are the region of the Earth surrounding the Equator. They are delimited in latitude by The Tropic of Cancer in the Northern Hemisphere at 23°26′12.5″ (or 23.4368°) N and the Tropic of Capricorn in the Southern Hemisphere at 23°26′12.5″ (or 23.4368°) S; these latitudes correspond to the axial tilt of the Earth. The tropics are also referred to as the tropical zone and the torrid zone. The tropics include all the areas on the Earth where the Sun contacts a point directly overhead at least once during the solar year - thus the latitude of the tropics is roughly equal to the angle of the Earth's axial tilt.

Subtropics

The subtropics are geographic and climate zones located roughly between the tropics at latitude 23.5° and temperate zones north and south of the Equator.

Tropical savanna climate

Tropical savanna climate or tropical wet and dry climate is a type of climate that corresponds to the Köppen climate classification categories "Aw" and "As". Tropical savanna climates have monthly mean temperatures above 18 °C (64 °F) in every month of the year and typically a pronounced dry season, with the driest month having less than 60 mm of precipitation and also less than 100 – [total annual precipitation {mm}/25] of precipitation.

Cold semi-arid climates

Regions with cold semi-arid climates Koppen World Map BSk.png
Regions with cold semi-arid climates

Cold semi-arid climates (type "BSk") tend to be located in elevated portions of temperate zones, typically bordering a humid continental climate or a Mediterranean climate. They are typically found in continental interiors some distance from large bodies of water. Cold semi-arid climates usually feature warm to hot dry summers, though their summers are typically not quite as hot as those of hot semi-arid climates. Unlike hot semi-arid climates, areas with cold semi-arid climates tend to have cold winters. These areas usually see some snowfall during the winter, though snowfall is much lower than at locations at similar latitudes with more humid climates. Areas featuring cold semi-arid climates tend to have higher elevations than areas with hot semi-arid climates, and tend to feature major temperature swings between day and night, sometimes by as much as 20 °C (36 °F) or more in that time frame. These large diurnal temperature variations are seldom seen in hot semi-arid climates. Cold semi-arid climates at higher latitudes tend to have dry winters and wetter summers, while cold semi-arid climates at lower latitudes tend to have precipitation patterns more akin to subtropical climates, with dry summers, relatively wet winters, and even wetter springs and autumns. Cold semi-arid climates are most commonly found in Asia and North America. However, they can also be found in Northern Africa, South Africa, Europe, sections of South America and sections of interior southern Australia and New Zealand.

Humid continental climate Category in the Köppen climate classification system

A humid continental climate is a climatic region defined by Russo-German climatologist Wladimir Köppen in 1900, typified by large seasonal temperature differences, with warm to hot summers and cold winters. Precipitation is usually distributed throughout the year. The definition of this climate regarding temperature is as follows: the mean temperature of the coldest month must be below −3 °C (26.6 °F) and there must be at least four months whose mean temperatures are at or above 10 °C (50 °F). In addition, the location in question must not be semi-arid or arid. The Dfb, Dwb and Dsb subtypes are also known as hemiboreal.

Mediterranean climate climate zone

A Mediterranean climate or dry summer climate is characterized by rainy winters and dry summers, with less than 40 mm of precipitation for at least three summer months. While the climate receives its name from the Mediterranean Basin, these are generally located on the western coasts of continents, between roughly 30 and 43 degrees north and south of the equator, typically between oceanic climates towards the poles, and semi-arid and arid climates towards the equator.

Diurnal temperature variation diurnal temperature variation is the variation between a high temperature and a low temperature that occurs during the same day

In meteorology, diurnal temperature variation is the variation between a high temperature and a low temperature that occurs during the same day.

Regions of varying classification

In climate classification, three isotherms means that delineate between hot and cold semi-arid climates — the 18°C average annual temperature or that of the coldest month (0°C or −3°C), the warm side of the isotherm of choice defining a BSh climate from the BSk on the cooler side. As a result of this, some areas can have climates that are classified as hot or cold semi-arid depending on the isotherm used. One such location is San Diego, California (at its main airport), which has cool summers for the latitude due to prevailing winds off the ocean (so the average annual temperature is below 18°C) but mild winters (average temperature in January, 14°C, and closer to the 18.0°C isotherm that separates tropical and subtropical climates than to the 0°C or −3°C isotherm for the coldest month that separates temperate and continental climates).

Charts of selected cities

Patos, Paraíba, Brazil
Climate chart (explanation)
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: [5]
Jaipur (Sanganer), India
Climate chart (explanation)
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: India Weather On Web
Niamey, Niger
Climate chart (explanation)
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: Deutscher Wetterdienst [6]
Port Louis, Mauritius
Climate chart (explanation)
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: World Meteorological Organization. [7]
Murcia, Spain
Climate chart (explanation)
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: Agencia Estatal de Meteorología [8]
Reno, Nevada
Climate chart (explanation)
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: NOAA [9]

See also

Related Research Articles

Temperate climate

In geography, the temperate or tepid climates of Earth occur in the middle latitudes, which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout the year and more distinct seasonal changes compared to tropical climates, where such variations are often small.

Continental climate

Continental climates often have a significant annual variation in temperature. They tend to occur in the middle latitudes, where prevailing winds blow overland, and temperatures are not moderated by bodies of water such as oceans or seas. Continental climates occur mostly in the Northern Hemisphere, which has the kind of large landmasses required for this type of climate to develop. Most of northern and northeastern China, eastern and southeastern Europe, central and southeastern Canada, and the central and upper eastern United States have this type of climate.

Oceanic climate a type of climate characterised by cool summers and cool winters

An oceanic climate, also known as a marine or maritime climate, is the Köppen classification of climate typical of west coasts in higher middle latitudes of continents, and generally features mild summers and mild winters, with a relatively narrow annual temperature range and few extremes of temperature, with the exception for transitional areas to continental, subarctic and highland climates. Oceanic climates are defined as having a monthly mean temperature below 22 °C (72 °F) in the warmest month, and above 0 °C (32 °F) in the coldest month.

In climatology, the term mesothermal is used to refer to certain forms of climate found typically in the Earth's temperate zones. It has a moderate amount of heat, with winters not cold enough to sustain snow cover. Summers are warm within oceanic climate regimes, and hot within continental climate regimes.

Climatic regions of India

India has a large variation in climate from region to region, due to its vast size. India experiences climate from four major climate groups. These can be further subdivided into seven climatic types. For ecological regions, see Ecoregions of India, for Regions see List of regions of India.

Tabernas Desert desert in Spain

The Tabernas Desert is one of Spain's semi-arid deserts, located within Spain's southeastern province of Almería. The Tabernas desert is located in the interior, about 30 kilometers (19 mi) north of the provincial capital, Almería, in the Tabernas municipality. Due to its high altitude and inland location, it has slightly higher annual rainfall and lower annual average temperature than coastal areas of Almeria. It is a nature reserve spanning 280 square kilometres.

Soto la Marina is a town in Soto la Marina Municipality located in the Mexican state of Tamaulipas. It was directly hit by Hurricane Alex in 2010. It is located on the banks of the Soto la Marina river, just up river from the small ocean port of La Pesca, and downriver from Ciudad Victoria, the capital of the State of Tamaulipas. 180 miles South of Brownsville, Texas, it is accessible from there via a highway in approximately 3 hours driving time.

Climate of Argentina

The climate of Argentina is a vastly complex subject, as the vast size of the country and wide variation in altitude make for a wide range of climate types. Summers are the warmest and wettest season in most of the country except in most of Patagonia where it is the driest season. Winters are normally mild in the north, cool in the center and cold in the southern parts experiencing frequent frost and snow. Because southern parts of the country are moderated by the surrounding oceans, the cold is less intense and prolonged than areas at similar latitudes in the northern hemisphere. Spring and autumn are transition seasons that generally feature mild weather.

Climate of Mexico

The climate of Mexico is highly varied. The Tropic of Cancer effectively divides the country into temperate and tropical zones. Land north of the twenty-fourth parallel experiences lower temperatures during the winter months. South of the twenty-fourth parallel, temperatures are fairly constant year round and vary solely as a function of elevation. The north of the country generally receives less precipitation than the south.

Humid subtropical climate category in the Köppen climate classification system

A humid subtropical climate is a zone of climate characterized by hot and humid summers, and mild winters. These climates normally lie on the southeast side of all continents, generally between latitudes 25° and 40° and are located poleward from adjacent tropical climates. While many subtropical climates tend to be located at or near coastal locations, in some cases they extend inland, most notably in China and the United States, where they exhibit more pronounced seasonal variations and sharper contrasts between summer and winter, as part of a gradient between the more tropical climates of the southern coasts of these countries and the more continental climates of China and the United States’ northern and central regions.

Kailu County County in Inner Mongolia, Peoples Republic of China

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East Ujimqin Banner Banner in Inner Mongolia, Peoples Republic of China

East Ujimqin Banner is a banner in the northeast of the Inner Mongolia Autonomous Region, People's Republic of China. It is under the administration of Xilin Gol League.

The climate in Spain varies across the country. Spain is the most climatically diverse country in Europe with 13 different Köppen climates and it's within the 10th most climatically diverse countries in the world. Five main climatic zones can be distinguished, according to Guzman geographical situation and orographic conditions:

Madrid and its metropolitan area has a Mediterranean climate which transitions to a cold semi-arid climate (BSk). According to Troll-Paffen climate classification, Madrid has warm-temperate subtropical climate and according to Siegmund/Frankenberg climate classification, Madrid has subtropical climate. However, the most widespread climate classification is that Madrid presents a climate of transition between the Mediterranean climate and the cold semi-arid climate (BSk), with warm summers and relatively cold winters with frequent frosts and occasional snowfalls.

Trewartha climate classification

The Trewartha climate classification is a climate classification system first published by American geographer Glenn Thomas Trewartha in 1966. It is a modified version of the Köppen-Geiger system, created to answer some of its deficiencies. The Trewartha system attempts to redefine the middle latitudes to be closer to vegetation zoning and genetic climate systems. It was considered a more true or "real world" reflection of the global climate.

References

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  5. Climate of Patos Access on January 16th, 2016.
  6. "Klimatafel von Niamey (Aéro) / Niger" (PDF). Federal Ministry of Transport and Digital Infrastructure. Retrieved 14 June 2016.
  7. World Weather Information Service-Port Louis, World Meteorological Organization. Retrieved 29 September 2012. }}
  8. "Valores Climatológicos Normales. Murcia - Alcantarilla". Aemet.es. Archived from the original on 2009-12-14. Retrieved 2013-09-08.
  9. "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration . Retrieved June 6, 2015.