© 2014 Pearson Education, Inc. Chapter 2 Lecture McKnight's Physical Geography 11e Lectures Chapter 4 Insolation and Temperature © 2014 Pearson Education, Inc. Andrew Mercer Mississippi State University

© 2014 Pearson Education, Inc. Learning Goals of This Chapter Define energy and explain how it is related to work and power. Explain the concept of internal (or kinetic) energy. Explain the difference between temperature and heat, and describe the scales used to measure temperature. Explain how shortwave radiation from the Sun differs from longwave radiation from Earth’s surface and atmosphere. Define electromagnetic radiation, and describe the electromagnetic spectrum.

© 2014 Pearson Education, Inc. Learning Goals of This Chapter Differentiate between radiation, absorption, reflection, scattering, and transmission. Differentiate between conduction, convection, and advection. Explain adiabatic processes and their importance to the movement of latent heat. Explain the energy budget and compare the percentages that result in Earth’s albedo, direct atmospheric heating, and the indirect atmospheric heating. Explain the indirect warming of the atmosphere by the Sun, and identify the name of this process.

© 2014 Pearson Education, Inc. Learning Goals of This Chapter Explain the variation by latitude of the amount of solar energy received by Earth. List the reasons that land masses warm faster than water bodies. List the reasons that land masses cool faster than water bodies. Compare the temperature patterns for the Northern Hemisphere to the Southern Hemisphere. Describe the circulation patterns in which energy is transferred from low latitudes to high latitudes. Differentiate between an environmental lapse rate and the average lapse rate.

© 2014 Pearson Education, Inc. Learning Goals of This Chapter Describe the cause of the average lapse rate. Define temperature inversion. Differentiate between the two types of temperature inversions. Describe the impact of altitude on global patterns of temperature. Describe the impact of latitude on global patterns of temperature. Describe the impact of land-water contrasts on global patterns of temperature. Describe the impact of ocean currents on global patterns of temperature.

© 2014 Pearson Education, Inc. Learning Goals of This Chapter Summarize the ways human activity is likely to be changing the global climate.

© 2014 Pearson Education, Inc. Insolation and Temperature The Impact of Temperature on the Landscape Heat, Energy, and Temperature Solar Energy Basic Warming and Cooling Processes in the Atmosphere Earth’s Solar Radiation Budget Variations in Insolation by Latitude and Season

© 2014 Pearson Education, Inc. Insolation and Temperature Land and Water Contrasts Mechanisms of Global Heat Transfer Vertical Temperature Patterns Global Temperature Patterns Climate Change and “Global Warming”

© 2014 Pearson Education, Inc. The Impact of Temperature on the Landscape All living things influenced by temperature Adaptation to temperature extremes Affects soil and bedrock exposure

© 2014 Pearson Education, Inc. Energy, Heat, and Temperature Definition of energy Forms of energy –Chemical –Kinetic –Potential –Radiant –Nuclear –Others Differences between work and power Importance of internal energy – energy at the molecular level Kinetic energy Potential energy

© 2014 Pearson Education, Inc. Energy, Heat, and Temperature Definition of temperature Measuring temperature Temperature scales –Celsius –Fahrenheit –Kelvin –Conversions between scales

© 2014 Pearson Education, Inc. Solar Energy Solar energy is electromagnetic energy Electromagnetic spectrum Wavelengths and frequency Three important areas on the spectrum –Visible radiation –Ultraviolet radiation –Infrared radiation Shortwave solar radiation, insolation

© 2014 Pearson Education, Inc. Solar Energy The electromagnetic spectrum

© 2014 Pearson Education, Inc. Basic Heating and Cooling Processes in the Atmosphere Radiation –Definition –Warmer objects radiate more effectively –Warmer objects emit at shorter wavelengths (e.g., the Sun) –Sun ultimate “hot” body in solar system –Blackbody radiators

© 2014 Pearson Education, Inc. Radiative processes Absorption –Body absorbs radiation –Good radiator, good absorber Reflection –Objects repel electromagnetic waves –Opposite of absorption Basic Heating and Cooling Processes in the Atmosphere

© 2014 Pearson Education, Inc. Radiative processes continued Scattering –Deflection of light waves by molecules and particles Transmission –Electromagnetic waves pass completely through a medium –Sunsets Basic Heating and Cooling Processes in the Atmosphere

© 2014 Pearson Education, Inc. Greenhouse Effect Some atmospheric gases transmit shortwave radiation, but not Earth’s longwave radiation Earth radiation held in by atmosphere Atmospheric blanket Basic Heating and Cooling Processes in the Atmosphere

© 2014 Pearson Education, Inc. Other heating types Conduction –Transfer of heat energy across a medium –Results from molecular collision –Air is a poor conductor Basic Heating and Cooling Processes in the Atmosphere

© 2014 Pearson Education, Inc. Convection –Heat transfer by vertical circulation –Molecules move in tandem (blobs of air) –Convection cell Advection –Horizontal transfer of heat in a moving fluid Basic Heating and Cooling Processes in the Atmosphere

© 2014 Pearson Education, Inc. Adiabatic cooling –Air rises and expands, molecular collisions decrease, so temperature decreases Adiabatic warming –Air sinks and compresses, collisions increase so temperatures increase Latent heat –Heat released or absorbed during a phase change –“Latent” since heat is not felt Basic Heating and Cooling Processes in the Atmosphere

© 2014 Pearson Education, Inc. Earth’s Solar Radiation Budget Albedo – fraction of insolation lost due to reflection Fraction of insolation is absorbed by land; land heats the atmosphere Remaining energy warms the atmosphere directly Earth, like the Sun, constantly emits radiation of lower energy Importance of the greenhouse effect in this balance

© 2014 Pearson Education, Inc. Earth’s Solar Radiation Budget Earth’s radiation budget

© 2014 Pearson Education, Inc. Variations in Insolation by Latitude and Season Any one location on Earth’s surface can have its insolation modified by a variety of factors, including the following: –Angle of incidence –Atmospheric obstructions –Day length Latitudinal radiation balance –Latitude of peak solar radiation moves between the tropics as seasons shift –Leads to seasonal patterns in insolation

© 2014 Pearson Education, Inc. Seasonal Variations in Insolation Variations in Insolation by Latitude and Season

© 2014 Pearson Education, Inc. Land and Water Contrasts Land heats and cools more rapidly than water due to the following: –Specific heat –Transmission –Mobility –Evaporative cooling

© 2014 Pearson Education, Inc. Land and Water Contrasts Differences in climate due to land–water contrasts

© 2014 Pearson Education, Inc. Mechanisms of Global Energy Transfer Need heat transfer to prevent constant warming at tropics and cooling at poles Circulation patterns in atmosphere and oceans transfer heat Storms assist in heat transfer to a lesser degree than the atmosphere and oceans

© 2014 Pearson Education, Inc. Mechanisms of Global Energy Transfer Atmospheric circulation –General circulation, outlined in Chapter 5 Oceanic circulation –Respond to average wind conditions over long time scales –Subtropical gyres

© 2014 Pearson Education, Inc. Mechanisms of Global Energy Transfer Ocean circulation (cont.) –Northern and southern variations Near Northern Hemisphere pole, landmasses lie so close that little flow can enter the Arctic Ocean. The effect is more pronounced in northern Pacific than northern Atlantic. In Southern Hemisphere, little land mass allows for constant westward belt of ocean circulation, the West Wind Drift. –Temperature patterns Low-latitude currents are warm. Poleward currents transfer warm water poleward. High-latitude currents transfer warm water east in Northern Hemisphere, and cool water east in Southern Hemisphere. Equatorial currents transfer cool water equatorward.

© 2014 Pearson Education, Inc. Mechanisms of Global Energy Transfer Ocean circulations (cont.) –Western intensification Water moving poleward moves more quickly than equatorward Due to a number of reasons, including ocean chemistry and the Coriolis effect

© 2014 Pearson Education, Inc. Mechanisms of Global Energy Transfer Ocean circulations (cont.) –Rounding out the pattern Northwestern portions of Northern Hemisphere receive cool water from Arctic Ocean Water pulled away from western coasts of continents results in upwelling Deep ocean circulation

© 2014 Pearson Education, Inc. Vertical Temperature Patterns Definition of lapse rate Environmental lapse rate Average lapse rate (about 6.5°C/km) Temperature inversions –Surface inversions –Upper-air inversions

© 2014 Pearson Education, Inc. Global Temperature Patterns Primary controls on global temperature –Altitude –Latitude –Land–water contrasts –Ocean currents

© 2014 Pearson Education, Inc. Global Temperature Patterns Seasonal patterns –Latitudinal shift in isotherms from one season to another –More pronounced over continents than water and over high latitudes than low latitudes

© 2014 Pearson Education, Inc. Global Temperature Patterns Global annual temperature variability

© 2014 Pearson Education, Inc. Global Temperature Patterns Monitoring global temperature patterns –Recent satellite imagery captures global average temperatures –Useful to get sea surface temperatures (SSTs) –Can provide measurements where data are sparse at the surface

© 2014 Pearson Education, Inc. Climate Change and “Global Warming” Climate data sources are suggesting global temperatures are getting warmer – global warming Temperatures on average have risen by 0.7°C in the last century, the fastest within the last 1000 years

© 2014 Pearson Education, Inc. Climate Change and “Global Warming” Rise in temperatures correlated with increased input of human-contributed (anthropogenic) greenhouse gases The IPCC

© 2014 Pearson Education, Inc. Summary Temperature affects both living and nonliving aspects of Earth’s landscape. Energy exists in many different forms, but cannot be created or destroyed. Temperature is a measure of the amount of kinetic energy in the molecules of a substance. Temperature is measured on three primary scales. The Sun is the primary source of energy for Earth’s atmosphere. Electromagnetic radiation is classified by wavelength.

© 2014 Pearson Education, Inc. Summary The Sun emits three important types of electromagnetic radiation, visible, infrared, and ultraviolet. Insolation refers to incoming solar radiation. Radiation is the process by which electromagnetic radiation is emitted by an object. Radiation can undergo several processes, including absorption, reflection, transmission, and scattering. The greenhouse effect makes Earth able to support life. Conduction is the transfer of heat through molecular collision.

© 2014 Pearson Education, Inc. Summary Convection is a vertical transport of heat in a fluid. Advection is the horizontal transport of heat. Adiabatic cooling and warming processes do not release or absorb heat. The global radiation budget describes the latitudinal distribution of temperature. Land surfaces heat and cool faster than water surfaces. Heat is transferred globally through atmospheric and oceanic circulations. The vertical temperature patterns in the atmosphere help describe vertical circulations.

© 2014 Pearson Education, Inc. Summary Global temperature patterns reflect the important controls of temperature, which include altitude, latitude, proximity to water, and ocean currents. Satellites are used to obtain global measurements of temperature with high accuracy. Global warming is the observed warming of the atmosphere. Temperature and carbon dioxide show a close relationship.