Chapter 4 Lecture Slides February 12th.pptx

Chapter 4 The Atmosphere and Earth’s Energy Budget Announcements: Cengage Chapter 4 is due February 13th at 11:59 PM Exam 1 is February 28th 4-3 Earth’s Energy Budget Earth’s energy budget - relationship between solar energy input, storage, and output within the Earth system. Accounts for incoming s...

Chapter 4 The Atmosphere and Earth’s Energy Budget Announcements: Cengage Chapter 4 is due February 13th at 11:59 PM Exam 1 is February 28th 4-3 Earth’s Energy Budget Earth’s energy budget - relationship between solar energy input, storage, and output within the Earth system. Accounts for incoming solar energy, what happens as it encounters Earth’s atmosphere where it is absorbed and stored how outgoing energy is lost to space. 4-3 Earth’s Energy Budget energy balance - the concept that the energy Earth receives from the sun is equaled (balanced) by return of that energy back to space we know that Earth has not gotten continually warmer or colder throughout its planetary history. The energy balance is an example of dynamic equilibrium The Earth-atmosphere system is constantly trying to maintain a balance between the energy that reaches Earth from the sun and the energy that flows from Earth back out to space. Do all locations on Earth receive the same amount of insolation? 4-3 Earth’s Energy Budget The majority of locations on Earth have local energy budgets that are unbalanced between incoming solar radiation and outgoing terrestrial radiation. The insolation received at a particular place depends on latitude, daylight duration, and seasonal regime. The latitudes of 38° North and South divide approximate equatorward zones that receive a solar energy surplus and poleward zones that experience annual deficits 4-4 Air Temperature Heat—energy being transferred from one substance or medium to another because of temperature differences. Temperature—measure of the average kinetic energy of molecules in a substance. Temperature scales Fahrenheit scale (°F) Celsius scale (°C) Kelvin scale (K) What is absolute zero? What is 16 F in Celsius? Kelvin? What is 380K in Celsius? Fahrenheit? 4-4 Air Temperature Why would there be a change in insolation daily? Diurnal changes create daily temperature lag When is the sun highest in the sky? When is it the warmest part of the day? Minimum near sunrise Why? 4-4 Air Temperature Based on this images, how does cloud cover change air temperature? 4-4 Air Temperature Air directly over either land or water can be strongly affected by the temperature of the surface below. Maritime Moderate temperatures Continentality Why do coastal cities have smaller daily temperature variations? Larger annual temperature range Larger diurnal temperature range Large bodies of water take a long time to warm up or cool down keeping the air temperature more moderate 4-4 Air Temperature Reflection - a surface’s ability to reflect solar energy (expressed as a percentage) is its albedo: Capacity of a surface to reflect sun’s energy Snow and ice (high) The higher the albedo, the lower the amount of energy absorbed, and vice versa. Horizontal movement of air: Advection. Winds blowing from an ocean to the land generally bring cooler temperatures in summer and warmer temperatures during winter. 4-4 Air Temperature Vertical temperature distributions Normal lapse rates “Normal” refers to the average worldwide conditions expected in the troposphere. 6.5°C/1000 m (3.6°F/1000 feet) Temperature inversion: reverse of the normal pattern of vertical distribution of air temperature 4-4 Air Temperature Controls of Earth’s surface temperatures: latitude, land and water distribution, ocean currents, elevation, landform barriers, and human activities. 4-4 Air Temperature Land and water distribution Specific heat of water: the amount of heat required to raise the temperature of 1 gram of material by 1°C. Ocean currents Clockwise in Northern Hemisphere Counterclockwise in Southern Hemisphere 4-4 Air Temperature Ocean currents Warm Current: a flow of sea water that moves like a river through the ocean and is relatively warmer than water in the ocean area that it flows through. Cold Current: a flow of seawater that moves like a river through the ocean and is relatively colder than water in the ocean area that it flows through. Gulf Stream the North Atlantic Drift, is an example of a warm ocean current that moves water poleward 4-4 Air Temperature Landform barriers: large mountain ranges that block air movements from one place to another can affect temperatures. Human activities Urban heat islands In cities, thousands of automobiles add heat to the air, whereas rural areas experience fewer vehicles. Deforestation 4-4 Air Temperature Horizontal distribution of temperature in January Horizontal distribution of temperature in July 4-5 Weather and Weather Climate Atmospheric conditions at a given time for a specific area Climate Describes an area’s average weather over 30 years Average conditions and deviations from average Think About It What function does ozone play in supporting life on Earth? Where and how is ozone formed? How is the atmosphere heated from Earth’s surface? What processes are involved? Explain the enhanced greenhouse effect and its impact on Earth’s energy balance. At what time of day does insolation reach its maximum and its minimum? Why is it that these times do not correspond with the times of the daily high and low temperatures? Would you expect places like Seattle to have a milder or a harsher winter than Grand Forks, North Dakota? Why? Convert the following temperatures: 20°C -> F 30°F -> C 10 °F -> C -> K