Environmental Science

Different Climatic Zones : Semi Arid Climate

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

• The northern arid regions in India comprise largely of the desert of Rajasthan, the Rann of Kutch and the semi-arid regions of Punjaband Gujarat. The Southern arid regions are in the rain shadow of the Western Ghats covering states of Maharashtra, Karnatakaand Tamil Nadu.

Hot semi-arid climates

• Hot semi-arid climates (type "BSh") tend to be located in the

tropics and subtropics.

• These climates tend to have hot, sometimes extremely hot,

summers and mild to warm winters. Snow rarely (if ever) falls

in these regions.

• Hot semi-arid climates are most commonly found around the

fringes of subtropical deserts. The most common variant of a

hot semi-arid climate, found in regions such as West Africa,

India, parts of Mexico and bordering areas in Texas, parts of

Southern California, and small parts of Pakistan experiences

the seasonal effects of monsoons and has a short but well-

defined wet season, but is not sufficiently wet overall to qualify

as a tropical savanna climate.

• In Australia, a large portion of the Outback surrounding the

central desert regions, lies within the hot semi-arid climate

regime.

• Hot semi-arid climates can also be found in sections of South

America such as the sertão and on the pole ward side of the

arid deserts where they typically feature a Mediterranean

precipitation pattern, with generally rainless summers and

wetter winters.

Cold semi-arid climates• Cold semi-arid climates tend to be located in temperate zones.

• They are typically found in continental interiors some distance

from large bodies of water.

• Cold semi-arid climates usually feature hot (often

exceptionally hot) and 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 are

sometimes subject to 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

Mediterranean 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 (primarily in Spain), sections of

South America and sections of interior southern Australia and

New Zealand.

• Location: Semiarid climate is always found on the outer edge of arid climate areas.

Think of semiarid as a transition climate between dry and water places.

- Sahel (edges of Sahara)

• Temperature: depends on the location/latitude (similar to arid)

• Precipitation: considered semiarid if it averages between 10-20 in/ year.

some years these places may get 20-40 inches of rain, but sometimes 5-10 inches.

• Vegetation: Scattered trees,shrubs,grasses.Adaptation to preserve water.

• Influnces climate: Seasonal changes in wind and ocean currents bring dry & wetter seasons

• Summers are moderately long and dry and like hot deserts

• Winters normally bring low concentration of rainfall.

• Summer temperatures usually average between 21-27 C.it normallydoes not go above 38 C and evening temperatures are cool at around 10 C.

• Major deserts of this type include the sage brush of Utah, Montana and Great Basin

Traditional Hot Climate Design:

• In hot dry (arid) climates windows are kept to a minimum to prevent the sun From entering the building.

• Bright stucco finishes are used to reflect light and keep the environment bright.

• The more harsh extreme deserts will accommodate even smaller windows then

the average desert environment to combat the harsher conditions. As windows

are located higher up on a building it can be beneficial for the windows to be

smaller since they are more likely to have an un-obscured view of the sky and light can enter more

• In many traditional desert architecture houses

courtyards exist in the center of the home. Upon

entering a home traditionally the courtyard is the only

space that is directly accessible to the exterior. This

also gives the opportunity to extend a view to beyond

the outside of the house if so desired. One of the most

important principles of the desert home is that all rooms

and are orientated towards the courtyard. Besides

being the social heart of the home this allows for air

circulation, ventilation and light to effectively enter the

home.

• Within homes space is occupied reflective of the

orientation. If space occupancy is static the most

occupied spaces will be in the southeast to receive

morning light before the day becomes too warm,

(Belakehal 2004). Other times depending on season

spaces will be occupied depending on the time of year.

In the winter the north part of the home is occupied to

allow for more light to enter the space from the south

via the courtyard and other openings. In the summer

occupancy exists in the south, where the wall is much

thicker on the exterior to the periphery of the building

and direct sunlight is not able to enter the space

through the courtyard.

Day lighting and glare problem in the

urban environment.

Dome shaped roofs are a part of natural cooling and

ventilation systems in hot arid climates, Yazd, Iran

Openings on the dome shaped roofs are ventilation and

day lighting elements, , Yazd, Central Iran,

A narrow alley to provide more

shadows in central Iran,

Section of a Bazar in central Iran.

Different kind of courtyards.

To illuminate the deepest parts

of the prayer hall, recessed and

screened windows are located

near the ceiling, (Belakehal,

Tabet Aoul, & Bennadji,

Adobe window in a

public building in

central Iran

Adobe window in a

public building in

central Iran,

Adobe window in a public

garden in central Iran,