INVESTIGATING THE GLOBAL CLIMATE or for the entire year Normal daily maxi mum and minimum temperatures for a given date or month are also frequently cited The average difference between nighttime low temperatures and afternoon highs may be less than 10 °F 6 °C in cloudy climates or at sea but over 30 °F 17°C in deserts The high est and lowest temperatures ever recorded at a site give an idea of the range of tempera tures one might experience living a lifetime in that location Precipitation data are also very impor tant in describing a location s climate Mean AVERAGE SEA LEVEL TEMPERATURES IN JULY Over 80 50 to 80 20 to 50 EOS 10 to 20 Under 10 A coPTONS MN A map of mean global surface temperatures for July shows the values adjusted to indicate what the temperatures would be if all the loca tions were at sea level To convert from degrees Fahrenheit to degrees Celsius subtract 32 and then divide by 1 8 I2
WHAT IS CLIMATE and extreme monthly amounts are often cited with snow often included as liquid equivalent precipitation Snow cover and evaporation data are also important Mean wind speed and prevailing direction humidity and daily hours of sunshine help complete the climate picture BON AVERAGE ANNUAL PRECIPITATION 40 N 20 2G s Inches Over 80 40 to 80 40s 20 to 40 Bos 10 to 20 Under 10 to s A coNPTONS MAP A map shows the mean global distribution of annual precipitation One inch equals 2 54 cm CLASSIFICATION OF CLIMATES No two locations have precisely the same cli mate but there are many useful schemes for classifying climates The ancient Greeks devised a simple scheme Noting the relationship 13
INVESTIGATING THE GLOBAL CLIMATE WORLD CLIMATE REGIONS A COMPTONS MAP Tropical climates Rainy Tropical tropical rainforest Subtropical climates Mediterranean dry summer Humid Subtropical Tropical Savanna Semiarid Tropical steppe Dry Subtropical Arid Tropical desert Polar climates J Polar Tundra Cyclonic climates Humid continental Long Summer Humid Continental Short Summer Subarctic taiga Polar Ice Cap Dry Continental Semiarid O Dry Continental Arid desert S Maritime Continental marine west coast Highland climates varies with altitude The climate regions of the world are based on patterns of average pre cipitation average temperature and natural vegetation They include A tropical subtropical cyclonic polar and highland climates 14
WHAT Is CLIMATE between temperature and latitude they divided Earth into five broad east west zones or klima two frigid polar zones two temper ate midlatitude zones and a torrid tropical zone One frigid zone lay in the Northern Hemisphere within the Arctic Circle the other in the Southern Hemisphere within the Antarctic Circle One temperate zone lay in the Northern Hemisphere between the Arctic Circle and the Tropic of Cancer the other in the Southern Hemisphere between the Antarctic Circle and the Tropic of Capricorn The torrid zone straddled the Equator between the two tropics While it accounted for latitude however this simple grouping of climates ignored other factors affecting temperature and climate The classification systems most widely used today are based on the one introduced in 1900 by the German climatologist Wladimir Köppen Köppen divided Earth's surface into climatic regions that generally corre sponded to patterns of vegetation and soils found throughout the world The boundar ies of these climatic regions were defined by using precise temperature and precipitation averages A unique letter system identi fied five major climate groups tropical rainy climates A dry climates B humid 15
