Katrina JuddLecture 9Urban Heat Islands The physical characteristics of urban areas create urban heat islands: large urban areas that are warmer than the surrounding countrysideThis is due to 4 factors:1. Lower albedos Urban Surfaces have lower albedos, so they have more: sensible heat radiating from the surfaces2. Irregular geometric shapes. Urban “canyons”: reradiate heat and halt wind flow 3. Air Pollution reduces insolation, but absorbs infrared radiation, and re-radiates it downward. Every city produces its own “dust dome” of pollution.4. Human activities In the summer, urban electricity production and use of fossil fuels release energy equivalent to 25-50% of insolation.In winter, urban-generated sensible heat averages 250% greater than arriving insolation, reducing winter heating requirements. Which are false?A. Urban areas are cooler than the surrounding countryside; they radiate less heat.B. Urban areas have a higher albedo than the surrounding countrysideC. Humans remove heat from cities through air conditioning and heating systems.D. The “canyon” effect of buildings means they re-radiate heat and halt wind flow. E. Urban areas are sometimes called “Urban Albedo Islands”Solar Energy The insolation receipt in just 35 minutes at the surface of the United States exceeds the amount of energy derived from the burning of fossil fuels in a year.The average building in the United States receives 6-10 times more energy from the Sun hitting its exterior than is required to heat the inside.T/F Approximately 3 months of insolation received at the surface in the US equals the amount of fossil fuels we burn.T/F A typical US building receives more sun from the outside than is needed to heat the inside.Temperature: a measure of the average amount of motion of individual molecules in matter. The point at which atomic and molecular motion in matter complete stops is absolute zero. As we shall see, its value differs in the three different temperature-measuring scales.Katrina JuddHeat: a form of energy that flows from one system or object to another because the two are at different temperaturesThere are three temperature scales: 1. Used in US: Fahrenheit2. Divided into 100 degrees using the decimal system (most countries use this): Celsius3. Starts at absolute zero, so readings are proportional to the actual kinetic energy in a material: kelvinThe temperature scales have three key measurement points:1. melting point of ice2. boiling point3. point at which atomic motion stops1.Melting point of ice: Fahrenheit (know for test): 32Celsius: (know for test): 0 Kelvin: (do not need to know for test): 2732.Boiling point of water:Fahrenheit (know for test): 212Celsius (know for test): 100Kelvin (do not need to know for test): 3733.Point at which atomic motion stops: Fahrenheit (do not need to know for test): -459.4Celsius (do not need to know for test): -273Kelvin (know for test): 0The freezing point for water is not included as a key measurement point because it varies between 32-40, depending upon its purity, volume, and conditions in the atmosphere.Which is FALSE?a) Temperature is a measure of the average amount of motion of individual molecules in matterb) Heat is a form of energy that flows from one system or object to another because the two are at different temperaturesc) The freezing point for water varies is always 32 ⁰ F.d) There is atomic motion in a frozen, snowy landscape. Matching:A. Divided into 100 degrees using decimal system. CelsiusB. Boiling point is 212 degrees FahrenheitC. Boiling point is 100 degrees CelsiusD. 0 is the point at which ice meltsCelsiusE. 0 is the point at which all atomic motion stops KelvinF. Used in the US FahrenheitG. Used in most countries CelsiusH. Used by some scientists KelvinKatrina JuddThere are four main temperature controls1. Latitude Insolation decreases as one moves away from the equator, so temperatures become cooleras latitude increasesT/F Temperatures become higher as latitude increases.2. Altitude/Elevation - Temperatures decrease with increasing altitude. This is because the density of the atmosphere decreases, so there is a loss in the atmosphere’s ability to absorb and radiate heat.- Altitude: refers to objects above the earth’s surface-Elevation: the height of a point on the earth’s surfaceT/F: The atmosphere gets denser with altitude.T/F: Elevation refers to distances on the ground, while altitude refers to distancesabove the ground.So, at high elevations the following patterns occur:1. Average air temperatures are: lower2. Surfaces gain and lose heat rapidly in the thinner atmosphere3. Night time cooling is greater4. Temperature range between day and night is greater than at lower elevations5. The insolation received is more intense. Which is true?A. Night time cooling tends to be less in mountainous places than at lower elevationsB. Surfaces lose heat more slowly at higher elevations because the atmosphere is denser there.C. The insolation received at higher elevations is less intense because of the thinner atmosphere.D. Average air temperatures are cooler at higher elevationsE. Temperature ranges between day and night are not as great at high elevations as they are at low elevations.3. Cloud Cover - As we’ve discussed, clouds moderate temperature, and their effect varies with cloud type, height and density. Here, we’ll look at the general rule, but we’ve learned that thin cirrus clouds vs. thick stratus clouds have very different effects.- At night, clouds act as insulation AND radiate longwave energy, preventing rapid energy loss. So, they tend to raise night time temperatures. During the day, clouds reflect insolation because they have high albedo.-So, in general, they lower daily maximum temperatures. But cirrus clouds are an exceptionWhich is False?A. Clouds tend to decrease night time temperatures.B. In general, clouds tend to decrease daytime temperatures.C. Cirrus clouds do not tend to decrease daytime temperatures.D. At night, clouds act as insulation.E. At night, clouds radiate longwave energy, which increases their ability to keep nights warm.Katrina Judd4. Land-Water Heating Differences Land and water store heat very differently, and the result is a big difference in climates across theglobe. There are 4 land-water temperature controls (ways they behave differently): 1. Evaporation2.