World climate regions

PPT ON WORLD CLIMATIC REGIONS

1. WORLD CLIMATE REGIONS Dr. Rajalekshmy.p.r Dept of Swasthavritta Amrita School of Ayurveda

2. INTRODUCTION Climate is the condition of the atmosphere at a certain place on earth. It is the long-term weather of an area and it includes weather conditions, weather extremes, droughts and rainy periods. Climatology is the study of climate. Climatic regions are areas with similar weather statistics.

3. INFLUENCING FACTORS Latitude Altitude Proximity to seas Air currents Land formation

4. LATITUDE A line of latitude is an imaginary line which joins all places having the same angular distance north or south of the equator. Equator 0 -longest line of latitude. Two poles are points 90˚ N and 90 ˚ S. Other important lines of latitude are tropic of cancer(23 1/2 ˚N), tropic of Capricorn 23 1/2 ˚S), the Arctic circle(66 1/2 ˚N) and the Antarctic circle(66 1/2 ˚S).  

5. ALTITUDE H eight above sea level or the height above the earth's surface. The higher the altitude, the lower the temperature will be. On average for every 1,000 metres higher you go the temperature will fall about 6.5 °C.

6. PROXIMITY TO SEAS Proximity to seas affects the temperature of a place because the sea temperature changes slower than land temperature. So the sea will keep coastal areas warmer than inland area during the winter and cooler than inland areas during the summer.

7. AIR CURRENTS P revailing winds mainly affect the precipitation of a region. As prevailing winds pass over the ocean, it picks up water vapours . Eventually condensation takes place and it rains. Prevailing winds also can have an impact on the temperature of a zone. For example, Because, winds coming from the north pole tend to be cold and dry, the regions the wind passes over may also become colder and drier.

8. LAND FORMATIONS Landforms affects the precipitation factor. Prevailing winds coming in from oceans usually contain a lot of moisture. Now as the air is forced up the windward side of a mountain, the air cools and condenses causing precipitation. Because all the moisture is lost on the windward side of the mountain, the leeward side receives no precipitation. This process is called the rain shadow effect. The presence of such land formation can cause some areas of a zone to receive more precipitation than others.

9. COMPONENTS INSOLATION incoming solar radiation- radiant energy received by the earth. TEMPERATURE how hot or cold the atmosphere is – i.e , how many degrees Celsius (centigrade) it is above or below freezing (0°C)point. ATMOSPHERIC PRESSURE T he weight of air resting on the earth's surface. Pressure is shown on a weather map, often called a synoptic map, with lines called isobars . PRECIPITATION moisture that falls from the air to the ground. WIND the movement of air masses from high pressure areas ( high ) to low pressure areas ( low ). The effect of this movement of air is to rebalance the pressure in the atmosphere .

10. 66 1/2 °S 66 1/2 °S SOUTH FRIGID ZONE 66 1/2 °N 66 1/2 °N NORTH FRIGID ZONE 23 1/2 °N 23 1/2 °S NORTH TEMPERATE ZONE TROPICAL OR TORRIDZONE SOUTH TEMPERATE ZONE

11. WORLD CLIMATIC TYPES Climatic zone type Latitude Climatic type Rainfall Equitorial zone 0˚-10˚N and S 1. Hot, wet equatorial Rainfall all year around: 80 inches Hot zone 10˚-30˚N and S 2. a) tropical monsoon b)Tropical marine 3. Sudan type 4. desert: a)Saharan type b) mid-latitude type Heavy summer rain: 60 inches Much summer rain: 70 inches Rain mainly in summer: 30 inches Little rain: 5 inches

12. Warm temperate zone 30˚- 45˚N and S 5. Western margin ( Mediterranean type) 6. Central continental(steppe)type 7. Eastern margin: a)china type b)Gulf type c)Natal type Winter rain:35 inches Light summer rain:20 inches Heavier summer rain:45 inches Cool temperate zone 45˚-65˚N and S 8. Western margin( british type) 9. Central continental(Siberian type) 10. Eastern margin(Laurentian type) More rain in autumn and winter:30 inches Light summer rain:25 inches Moderate summer rain: 40 inches

13. Cold zone 65˚- 90˚N and S 11. Arcti c or polar Very light summer rain: 10 inches Alpine zone 12. Mountain climate Heavy rainfall(variable)

14. EQUITORIAL CLIMATE

15. LOCATION Extends generally between 10˚N and 10˚S latitudes. Includes parts of Asia, Africa and South America which are crossed by equator. Africa- Zaire(Congo basin), the Guinea coast in West Africa. South America- Amazon Basin, coastal Columbia. Asia- Malaysia, Indonesia, Papua in New Guinea, Indonesia and peninsular part of Thailand .

16. CLIMATIC CONDITIONS High temperature and heavy rainfall throughout the year. Duration of sunlight is 12 hours daily throughout the year. Temp condns range between 25˚c and 30˚c. Annual range of temp is less than 3˚C.

17. RAINFALL Receives high annual rainfall. Rainfall well distributed during all the months of the year. Amount ranges from 150 cm to 350 cm or more. Periods of maximum rainfall- April and October/November Least rainfall- June and December Rainfall occurs almost everyday in afternoon b/w 12 noon & 3 p.m. Torrential rainfall accompanied by thunder and lightning. Combination of high temperature and high humidity.

18. TROPICAL SUDAN CLIMATE

19. LOCATION The tropical grassland/ S avanna region occurs in the transitional zone b/w equatorial forest region and tropical deserts. Latitudinal limits- 10˚ N to 20˚ S Savanna is distributed in the southern continents of Africa, South America and Australia.

20. AFRICA Savanna are most extensive, covering a belt around equatorial region in both hemispheres. Northern hemisphere- interior areas of West Africa. Includes parts of Senegal, Mali, Ivory Coast, Ghana, Togo and Nigeria. Covers parts of Sudan, Chad, Cameroon and Central African Republic. Southern hemisphere- tropical grassland cover parts of Angola, zaire , Zimbabwe, Mozambique, Tanzania and Kenya. SOUTH AMERICA Grasslands occur in two separate areas. Larger one covers interior parts of Brazilian highlands and regions of Bolivia and Northern Argentina. Smaller area lies to north of equator and covers the Guiana highlands and Orinoco basin in parts of Venezuela and Colombia. AUSTRALIA Grasslands occur as a wide belt extending from west to east, north of the tropic of Capricorn . Includes parts of Western Australia, Northern Territory and Queensland.

21. CLIMATIC CONDITIONS Hot wet summers and warm dry winters Mean monthly temp in summer->30˚C N orthern hemisphere- though sun is overhead in June, hottest month is April or May. Southern hemisphere-October or November is the hottest month not December. Temp in winter-20˚C Annual range of temp-10˚C Diurnal range of temp is 15-20˚C

22. RAINFALL Gets moderate annual rainfall, varies from 125 cm on the margin of equatorial region to 25 cm on the margin of tropical desert. Rainfall occurs in the summer season. Torrential rainfall associated with thunderstorms. Dry trade winds blowing over West Africa in winter are called Harmattan (doctor). Relief from humid air of the Guiana coastlands and encourage evaporation, which has cooling effect on skin.

23. TROPICAL MONSOON CLIMATE

24. DISTRIBUTION This climatic belt lies roughly b/w 10 ° and 25 ° North and South of the equator; Indian Subcontinent extends to 30 ° N. Areas with tropical monsoon climate are India, Pakistan, Bangladesh, Srilanka, Myanmar, Southern China, Cambodia, Vietnam, the islands of Hainan, Taiwan, Philippines, Central America, West Indies, Madagascar, Guinea Coast and Eastern Brazil.

25. CLIMATIC CONDITIONS In summer when sun is overhead on Tropic of Cancer and Northern hemisphere is intensely heated low pressure in Central Asia. High pressure develops in southern hemisphere in interiors of Australia. Wind blows outward from Australia as South East monsoon but on crossing equator get deflected towards west and drawn towards low pressure areas in Indian Subcontinent, blowing as South West monsoon. In winter, sun is overhead on tropic of Capricorn. Central Asia is cold, high pressure is created with out blowing dry winds- North East Monsoon. On crossing equator, winds are drawn to low pressure centre in Australia , blowing as North West Monsoon.

26. SEASONS COOL DRY SEASON October-February North East monsoon prevailing-winds are dry but from Bay of Bengal, they pick up moisture which is deposited in South East Indian Peninsula(70 cm of rain). Skies are clear and temperature are low. HOT DRY SEASON March to mid June Temp rises sharply with sun’s apparent movement northwards to tropic of cancer. Intense heat, low relative humidity and clear skies make day temp unbearable(35 ° C). Coastal regions experience relief due to moderating influence of sea. Dust storms in north are very common.

27. RAINY SEASON Mid June to end of September Torrential rain experienced across the country with south west monsoon. Maximum rainfall in these 4 months. Coastal areas and windward slopes of mountain experience 300 cm of rain. RETREATING MONSOON October-November South west monsoon begins to leave the shores of India and North west monsoon advances towards north.

28. HOT DESERT CLIMATE

29. LOCATION Occur on the western margins of continents in the belt of 15 ° and 30 ° North and South latitude(tropical deserts). Largest desert- Sahara desert in North Africa (parts of Egypt, Sudan, Libya, Algeria, Mali, Niger, Chad and other countries). Kalahari desert-smaller and located in south west Africa (parts of Angola, Namibia, Botswana and South Africa). In Asia, tropical desert extends from Arabia to Thar desert in Pakistan and India(parts of Iraq, Iran and other countries of south west A sia. North America- tropical deserts cover parts of California, Arizona and Nevada states of US. Peruvian desert in SA extends along pacific coast to west of Andes range. Great Australian desert-second largest desert in area(40% of total area of Australia).

30. CLIMATIC CONDITIONS Hot deserts get less than 25 cm annual rainfall. Desert are located in sub tropical high pressure belts. Regions of descending air warming of air high pressure reduced R.humidity No possibility of rainfall in these regions.

31. CHARACTERISTICS Western margins are extremely dry because trade winds blow towards them from interior of continents as off-shore winds. Hottest month has mean temp less than 30 ° C. During night, clear skies encourage rapid radiation of heat from land and temp falls rapidly. Diurnal range of temp varies from 20 ° C to 30 ° C. Night temp during summer may drop to less than 20 ° C. During winter, coolest month may have temp of less than 20 ° C. Annual range of temp -15 ° C

32. MEDITERRANEAN CLIMATE

33. MEDITERRANEAN REGIONS Land along the margins of the Mediterranean sea in Europe, Asia and Africa. Europe- south Portugal, Spain, France, Italy, Yugoslavia, Greece. Asia- parts of coastal areas of Turkey, Syria, Lebanon and Israel Africa- coastal areas of Algeria, Morocco, Libya, Tunisia Region around Cape town in South Africa

34. Warm dry summers and cool wet winters. Receives moderate rainfall. Summer- mean temp of hottest month is 20-25 ° C. During day time, temp may reach maximum of 30 ° C. Nights are cool in summer as clear skies radiate heat rapidly from earth’s surface. During winter, mean temp of coolest month varies b/w 5 ° and 15 ° C. F rosts occurs rarely and only night temp falls below 0 ° C. CLIMATIC CONDITIONS

35. LOCAL WINDS Local winds causes sudden changes in temp. Southern shores of Mediterranean seas are affected by hot and dry winds, called Sirocco(blows from Sahara desert and carry a large amount of dust). Santa Ana-hot dry wind that blows from desert region towards Los Angeles region of California. During winter, cold local winds called Mistral descends from Alpine ranges along Rhine valley of S.France (great force damages cultivated crops and trees).

36. RAINFALL Moderate rainfall in winter and drought in summer. A nnual rainfall: 35 cm-75 cm. Rainfall is minimum along margins of desert. Maximum rainfall received on hill range adjoining the coast. Clear skies and sunshine are common throughout the year. Bright sunny weather attracts tourists throughout the year.

37. TEMPERATE CONTINENTAL CLIMATE

38. LOCATION Located in interior of continents, in middle latitudes of 40 ° -55 ° north and South. In Europe, temperate grasslands extend to north of Black Sea and Caspian Sea. In Asia, grasslands extend eastwards into west Siberia, north China and Manchuria. North America-cover parts of United States and Canada. South America-cover parts of Argentina and Uruguay.

39. CLIMATIC CONDITIONS Short warm summer and long cold winter. Rainfall is moderate and variable. During summer, hottest month has temp of 15 ° -25 ° C. Maximum temp during day time may exceed 30 ° C. Clear skies favour rapid heating of land during day. During night, clear skies allow rapid radiation of heat from land. Diurnal range of temp is quiet large. During winter, land is covered with snow with only few hours of sunshine. A nnual range of temp: 20 ° -25 ° C.

40. RAINFALL Annual rainfall varies from 25cm to 60cm. Rainfall is accompanied with thunder and lightening. Rainfall comes in light showers spread over many rainy days. Snowfall during winter season.

41. TEMPERATE CONTINENTAL(SIBERIAN) CLIMATE

42. LOCATION The coniferous forests, Taiga region occurs as a broad continuous belt in the latitudinal zone of about 55 ° N to 70 ° N. Occurs b/w Tundra region to north and temperate grassland region to the south. Covers northern part of Scandinavia(Norway, Sweden and Finland). North America-covers parts of Southern Alaska and Canada and extends from pacific coast to Atlantic Coast.

43. CLIMATIC CONDITIONS Short warm summer season of 4 months and long cold winter season. Summer- warmest month have mean temp of 20 ° C. Max temp during daytime reaches 30 ° C. Winter season lasts for 8-9 months with mean temp of coldest month less than -10 ° C. Duration of sunlight may be about five or six hours only. Cold polar winds blow over Canada and Europe called blizzards.

44. RAINFALL Average rainfall is about 50cm. Varies from 30-100cm depending on distance from seas. Rainfall is distributed throughout the year and there is no marked dry season. Maximum rainfall in summer. During winter, snowfall is common. An under layer of permafrost in some areas.

45. ARCTIC CLIMATE

46. LOCATION Tundra region occurs in North Polar region beyond the Arctic circle. Tundra region covers coastal strips of Arctic ocean in North America, Europe and Asia. The main areas are coastal strips of Alaska, Canada and Greenland.

47. CLIMATIC CONDITIONS Short cool summer and long cold winter. On June 21 , when sun is overhead over tropic of cancer, Arctic region experiences Midnight Sun i.e , sun neither rises nor sets. All places north of the Arctic circle see the sun throughout the summer, while south of Antartica sun does not rise during this period. Converse condns occur when sun shines on tropic of Capricorn on Dec 23. Summer- Sun never sets for two or three months, remains over horizon at a low angle. W armest month has temp of less than 10 ° C. Mean temp of winter season is about -30 ° C. Permanently frozen subsoil-permafrost.

48. RAINFALL Cold desert Annual rainfall less than 25cm. Rainfall is of cyclonic origin owing to the ascent of warm air from south over cold air from north. Coastal regions receive maximum rainfall in autumn or winter. Precipitation occurs in the form of rainfall, snowfall or sleet. Accumulation of snow which has fallen for many years. Only a thin surface layer of snow gets melted during the short summer season.