domingo, 21 de octubre de 2018

UNIT 5. THE EARTH'S MAJOR BIOCLIMATIC ZONES.

THE MAJOR BIOCLIMATIC ZONES: THE TORRID ZONE

General characteristics

Location: between the tropics of Cancer and Capricorn.
Main characteristic: a very high temperature, always over 18ºC, but can distinguish two types:

The equatorial bioclimate.

Location: located next to the Equator areas.

Location of equatorial climates.
Source: By Koppen_World_Map_Hi-Res.png: Peel, M. C., Finlayson, B. L., and McMahon, T. A.(University of Melbourne)derivative work: Me ne frego (talk) - Koppen_World_Map_Hi-Res.png, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14798010

Main features

  • Temperatures are consistently high, around 25 ° C. In addition, the atmospheric temperature range is very narrow, only 3 ° C.
  • Precipitation levels exceed 1,500 mm and are distributed equally throughout the year. As a result there is only a season, hot and humid.
  • The rivers are regular and have a high amount of wáter.
  • The vegetation is characterized by the appearance of the jungle or rainforest: dense forest, which remains green throughout the year. It has two main characteristics:
  1. It is divided in several layers according to the height of the different vegetation species.
  2. It consists of a huge of variety of vegetal species.
Rainforest canopy.

Singapur's climograph. A good example of an ecuatorial bioclimate.



The bioclimate tropical.

Tropical humid climates.
Source: By Koppen_World_Map_Hi-Res.png: Peel, M. C., Finlayson, B. L., and McMahon, T. A.(University of Melbourne)derivative work: Me ne frego (talk) - Koppen_World_Map_Hi-Res.png, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14798346

Tropical dry climates.

Location: extends from the equator to the two tropics.

Main features:
  • High temperatures, always above 18 ° C, but had a wider atmospheric temperature range, between 3 and 10 ° C.
  • Precipitation levels are high, between 750 and 1,500 mm, but irregular, making it appear two seasons: a rainy summer and a dry season of winter season.
  • The rivers are irregular.
There are two subtypes:
  • humid tropical area with a three-month dry season or less.
  • dry tropical zone or savanah with dry season of more tan three months.
The vegetation, which depends on the levels of precipitation. We can distinguish:
  • tropical Woodland, less dense than the equatorial rainforest.

Tropical humid rainforest, India.
Source: By Aditya thaokar (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
  • Savannah, it consists of:
  1. tall grasses that grow during the wet season and die during the dry season.
  2. Scrub plants and trees such as the acacia and baobabs.
Grassland, Africa.
Acacia, Kenia.


Manaus' climograph. A good example of a humid tropical bioclimate.


Average rainfall: 1.800 mm. Average termperature: 26.9 ºC.
Kolkata's (Calculta) climograph, a good example of a tropical dry bioclimate.



Extenal links:

Ecuatorial bioclimate.


NOTE: many of these pages does not use the Celsius scale or the metric system. You have to make the conversion of the Fahrenheit degrees to Celsius degrees and of the inches to mm.

Fahrenheit to Celsius conversion chart:

Inches to milimeters:

Examples of places with a continental bioclimate.

Tropical dry bioclimate:


Examples of places with a tropical dry bioclimate.

Brasilia: https://weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,Brasilia,Brazil
https://en.climate-data.org/location/852/



THE MAJOR BIOCLIMATIC ZONES: THE TEMPERATE ZONE.

Location and main characteristic.

Location: between the tropics and the polar circles.
Main feature: the contrast of temperature and as a consequence the apparition of several seasons.
We can distinguish three subtypes: mediterranean, oceanic and continental.

The mediterranean bioclimate.

Location: around the Mediterranean Sea, Western America (California), Africa and Australia.


Characteristics:
  • Little contrast of temperature, since it is close to the sea. Hot summers and mild winters.
  • Moderate precitation levels between 300 and 800 mm per year.
  • Dry season during the summer.
  • The characteristic vegetation is the mediterranean woodland with:
  1. Small perenial (they retain its leaves along the year) trees (holm oak, cork).
  2. Shurbs (thyne, rosemary etc).

Holm Oak (Encina)

Rosemary (romero).
Thyne (tomillo).


Average temperature: 15ºC. Rainfall: 420 mm.


The oceanic bioclimate.

Location: the western border of the continents.
Characteristics:
  • Moderate temperature due the influence of the sea.
  • Mild winters (never below -3ºC) and cool summers (not more than 22ªC).
  • High precipitacion levels (more than 800 mm).
  • Rivers with a high volume of water.
Vegetation is deciduous (vegetation which lose their leaves seasonally) woodland made up of:
  • tall trees with large leaves that fall in autum (oak, beech).
Beech (haya).
Beech in winter.

Oak tree (in spanish, roble).
  • Scrubland and grass.
Grassland, Cork (Ireland).

Continental bioclimate.

Location: in inland continental regions.
Characteristics:
  • Huge contrast in climatic temperature due to the distance from the sea.
  • Very cold winters (temperatures below -3ºC) and hot and warm summers.
  • Moderate precipitation levels (300-800 mm) that fall mostly during the summer.
Yakutsk, Siberia. Average temperature in july: 20ºC.
Yakutsk, Siberia. Average temperature in january -38ºC.
About the continental vegetation we have to distinguish between the:
  • Taiga or coniferous woodland: trees with needle shpaed leaves (pine, fir trees) along with grassland.
Taiga, Siberia.
Fir trees (in spanish, abetos), Florida.
Fir tree leaves.
Pine tree (in spanish, pino).


  • steppes without trees due to the low precipitation levels.
Steppes, Mongolia.










External links:

Mediterranean bioclimate:

NOTE: many of these pages does not use the Celsius scale or the metric system. You have to make the conversion of the Fahrenheit degrees to Celsius degrees and of the inches to mm. Fahrenheit to Celsius conversion chart:
Inches to milimeters:
Examples of places with a mediterranean bioclimate.

Oceanic bioclimate:

NOTE: many of these pages does not use the Celsius scale or the metric system. You have to make the conversion of the Fahrenheit degrees to Celsius degrees and of the inches to mm. Fahrenheit to Celsius conversion chart:
Inches to milimeters:
Examples of places with a oceanic bioclimate.

Continental bioclimate:

Examples of places with a continental bioclimate.



Location: deserts appear across the torrid and temperate zones and cover around a 30% of the Earth's landmass.




Characteristics:
  • Aridity.
  • Irregular and low precipitation levels. We can distinguish between:
  1. Absolute deserts, receive less than 150 mm of rainfall per year and all months are dry.
  2. Steppes or semiarid deserts, receive between 150 mm and 750 mm and there are least seven dry months.
Sahara desert. an example of absolute desert. In most ot the Sahara desert, the average anual precipitación level does not reach 20 mm.

Desierto de los Monegros, Saragossa, Spain. A example of semiarid desert with a precipitation level of 350 mm per year.
  • Sharp contrasts of temperature due to the lack of atmospheric humidity. There are high temperatures during daytime and cold nights.
Sahara desert at night. During nightime temperature drops below 0ºC.

  • Rivers only carry water when it rains. The rest of the time its riverbed is dry. This stational rivers are called wadis.
Nachan Paral Wadi, Israel

Torrid desert climates.

  • Location: near the tropics due to the permanent high pressure.
High pressure over the Sahara desert.
  • The most important are the Sahara, the Great Sandy, Atacama, the Victoria, the Kalahari, Mojave, Sonoran, Thar and Iranian deserts.
  • High temperatures all year along, but with sharp contrast between:
  1.  hot days
  2.   cold nights.

Temperate desert climates.

  • Location: the inland areas of the continents due to:
  1.  the excessive distance from the sea 
  2.  The rain-shadow effect: the mountainous terrain that acts as a rain barrier (Patagonia).
  • The most important the Western Turkestan, Takla Makan, Gobi, Mojave and Patagonia deserts.
  • Huge contrast between very hot summers and vey cold winters.

Desert vegetation.

Desert vegetation is very scarce and has to adapt to aridity. Its main characteristics are:
  • Roots which spreads across the surface or reach deep below the ground to capture water.
  • Presence of fleshy stems to store water.
Cacti use their fleshy stems to stor wáter.
  • Small leaves or spikes to reduce evaporation.
Cactus spikes.
  • Can germinate with light raining and produce seeds which germinate with the next rainfall.
Cactus flowers.
We can distinguish two types:
  • Deserts : low-lying and spread vegetation. The main species are:
  1. Cactus.
  2. Thorny shrubs.
  3. In oasis, abundant vegetation, such as palm trees.

Cacti,Arizona desert

Crucifixión thron, Mojave desert.

Palm trees, oasis.

  • Steppes, low-lying grasses and iolated shrubs.

Shrub, steppes.

THE MAJOR BIOCLIMATIC ZONES: THE FRIGID ZONE AND MOUNTAINS

THE FRIGID ZONE.

 

Geographical distribution.







Location: between the polar circles and the poles.
Characteristics: harsh cold, limited light and low precipitation levels.
We can distinguish two different zones: 
  • the glacial environment (ice caps), located between the 75th parallel and the poles. In the North, Greenland and in the south Antarctica.
  • the periglaciar environment or the edges of the polar regions (tundra). Includes the far northern regions of North America, Europe an Asia and in the southern hemisphere the far southern regions of Argentine and Chile.

The polar climate: dominant cold.

Main characteristics:
  • Low temperatures all year around (never above 10ºC). We have to distinguish between the:
  1. Ice caps, always bellow zero degrees.
  2. Tundra, during the summer temperatures rise above 0ºC.
  • Scarce precipitations, generally as snow.
  1.  Ice caps, almost no precipitation.
  2. Tundra, below 250-300 mm per year.
  • Most of water apperars in solid form (ice). There are differences:
  1. Ice caps, only ice.
  2. Tundra, liquid water during the sumer. Large acumulations of ice on the permantly frozen subsoil (permafrost).

Marie Byrd Land, Antarctica.

Permafrost, Tundra.

Polar vegetation.

In the polar caps there is no vegetation.
In the tundra, vegetation is adapted to the very harsh conditions:
  1. little light.
  2. low temperature.
  3. strong winds
  4. poor soils.
We are goint to find:
  1. low-lying plants, such as mosses (in spanish, musgo) and lichens (in spanish, liquen).
  2. Shrubs, such as dwarf willows.

Mosses, Tundra

Dwarf willows

 

 

MOUNTAIN BIOCLIMATE.

Location.

Mountain bioclimate is azonal, it can be found at any latitude.
We can distinguish two zones:
  • low mountain 
  • high mountain or alpine. Here average temperature does not rise above 10ºC and there are no trees.

Characteristics:

High altitude determine the climatic elements:
  • Low temperatures: temperature drops 0.6ºC for every 100 metres above sea level.
  • High precipitacion levels until you reach 1.000 to 2.000 metres. Then starts to decrease.
  • Rivers are irregular
In the temperate zone we have to distinguish between two aspects (aspect: direction that a topographic slope faces):
  • sunlit aspect (in spanish, solana), faces the Sun directly: higher temperatures with greater daytime and thermal contrasts.
  • shaded aspect (in spanish, umbría): lower temperatures, lower thermal contrasts.
 

Mountain vegetation.

Vegetation has to adapt to harsh conditions.
We can distinguish several altitudinal zones according to the distance from the base of the mountains:
  • Woodlands. We have to distinguish between:
  1. Equatorial rainforest and tropical woodland in the torrid zone.
  2. Deciduous woodland (oak trees and beeches) and coniferous woodland (pine and fir trees).
Deciduous Woodland. Alps.
Source: By Gabriel HM - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=50473707
Tropical Woodland, Himalaya (2.000 m).
Source:
https://www.flickr.com/photos/38019504@N04/6271593046/
  • Scrubland and pastures.
  • Moos and lichens.

External links:

http://earthobservatory.nasa.gov/Experiments/Biome/biotundra.php





















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