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CLIMATE. Chapter 14. 14.1 What is Climate?. Climatology. Climatology is the study of Earth’s climate and the factors that affect past, present, and future climatic changes Pertains to long-term weather patterns of an area More than average weather conditions
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CLIMATE Chapter 14
Climatology Climatology is the study of Earth’s climate and the factors that affect past, present, and future climatic changes • Pertains to long-term weather patterns of an area • More than average weather conditions • Describes annual variations of temperature, precipitation, wind, and other variables • Details extreme fluctuations in these variables over time
Normals Data used to describe an area’s climate are compiled from meteorological records from thousands of locations around the world. Data includes daily high and low temperatures, amounts of rainfall, wind speeds and direction, humidity, and air pressure. Once gathered, data is averaged on a monthly or annual basis over a period of at least 30 years to determine the standard values (normals) for a location.
Factors that Influence Climate Latitude • Based on solar radiation and how the Sun’s rays strike the Earth • The tropics refers to the area between 23.5oS and 23.5o north of the equator • Receives the most solar radiation • Temperatures are warm year-round • The temperate zones lie between 23.5o and 66.5o north and south of the equator • Temperatures are moderate • The polar zones lie from 66.5o north and south of the equator to the poles • Solar radiation strikes at a low angle • Temperatures are almost always cold
Topographic Effects Air Masses Distinct origin due to difference in solar radiation Depends on where formed (land or water) Water heats and cools more slowly than land Coastal regions are warmer in winter and cooler in the summer months Temperatures in troposphere decrease with altitude, so mountain climates are typically cooler than sea level In addition, climates differ on each side of the mountain due to the rising and sinking of air
Microclimates Sometimes, the climate of a small area can be much different from that of the larger surrounding area. A localized climate that differs from the surrounding regional climate is called a microclimate. In mountainous areas, the climate becomes cooler with elevation. In an urban area, the climate is warmer due to large areas of asphalt and concrete buildings.
Heat Island Area where the climate is warmer than in surrounding rural areas Large areas of asphalt and concrete radiate far more heat into the air than grasslands, wooded areas, and bodies of water This causes greater changes in temperature with altitude, which causes convection currents that produce increased cloudiness and up to 15% more precipitation in cities Heat Islands are examples of climatic change on a small scale
The Earth’s climate is in a constant state of change.Changes take place over both long and short periods of time.Geologic records show Earth was once colder or warmer than it is today. Short-Term Climate Changes Seasons Short-term periods caused by regular variations in daylight, temperature, and weather patterns During summer in the Northern Hemisphere, the North Pole is tilted toward Sun During winter in the Northern Hemisphere, the North Pole is tilted away from Sun The opposite is true of the Southern Hemisphere Long-Term Climate Changes Ice Age • Period of time where much of Earth was covered by sheets of ice • The average global temperature decreased by an estimated 5 oC • Snowfalls increased throughout Earth, which sparked the advance of existing ice sheets • Ice ages alternate with warm periods (interglacial intervals) in which we are currently experiencing • The most recent ice age ended only 10,000 years ago
El Nino • A warm ocean current that occasionally develops off the western coast of South America • Brings wet weather to areas that are normally dry (excessive flooding) • Brings dry conditions to areas that are normally wet (extreme drought) • Leads to extensive property damage • Most devastating to tropical regions • Positively affects tropical disturbances from reaching hurricane strength storms in the Atlantic Ocean
The Greenhouse Effect The retention of heat by the atmosphere results in the Greenhouse Effect, which is the natural heating of the Earth’s surface caused by greenhouse gases. Without the Greenhouse Effect, life as we know it would NOT exist on Earth as our planet would be super cold! Meaning, we could not sustain life without it. On the other hand, an increase in the greenhouse effect could cause our planet to be hot. Scientists believe that it may be possible to increase or decrease the greenhouse effect by changing the amount of atmospheric gases… specifically carbon dioxide Any Increase in the amount of these gases could result in the increased absorption of radiation. Currently, levels of carbon dioxide in the atmosphere ARE increasing – which can lead to a rise in global temperatures.
Global Warming Global warming is a rise in global temperatures. Over past 200 years, temperatures have increased globally, with the warmest years on record having occurred over the past two decades (20 years). If this continues polar ice caps might melt and sea levels will rise, leading to flooding. Global warming can also cause an increase in the frequency of severe storms.
Protecting our Planet Impact of Human Activities Automobiles serve as the prime source of atmospheric CO2 Burning of fossil fuels results in the release of CO2 and other gases into atmosphere Deforestation is the massive removal of trees, which increases the CO2 into atmosphere because vegetation removes carbon dioxide during photosynthesis Environmental Efforts We can conserve energy, as individuals, to combat global warming Conservation of energy helps reduce the consumption of fossil fuels Easy ways to conserve energy include: Turning off appliances and lights Turning down thermostats during the winter Recycling Riding bikes for transportation… or walking
