Course ERAU WX-201

WX 201 Test 1 Questions and Answers In the atmosphere Cold air sinks and warm air rises Weather State of the atmosphere with respect to wind, temperature, moisture, pressure, etc. Climate Average or generally prevailing conditions Most abundant gases Nitrogen (78), Oxygen (21), Argon (.93) Which gas has a variable concentration, dependent upon location? Carbon dioxide, methane, ozone, water vapor What are the most common greenhouse gases? CO2, Methane, Ozone How do the following quantities change with height; Density More molecules near the surface How do the following quantities change with height; Pressure Decreases as you go up in the atmosphere How do the following quantities change with height; Temperature Decreases as you go up in the atmosphere Lapse rates and temperature inversions Rate at which the air temperature decreases with height Negative lapse rate/temperature inversion Temperature increases with height Positive lapse rate Temperature decreases with height Four layers of the atmosphere Troposphere, Stratosphere, Mesophere, Thermosphere Four layers of the atmosphere; Which layer is the warmest? Thermosphere Four layers of the atmosphere; Which layer is the coldest? Mesosphere How does temperature change with height in each layer? Mesosphere: As the altitude increases, the air temperature decreases. Troposphere layer, has a decrease in temperature with altitude increase. Thermosphere: As the altitude increases, the air temperature increases What is the relationship between temperature and kinetic energy? Temperature is the measure of a substance's average KE. Faster motion=warmer temperature. How is air temperature related to density? Cold air is more dense than warm air Heat Capacity Amount of heat energy absorbed by a substance Specific Heat Heat capacity per unit mass Heat capacity/specific heat; How do they relate to the temperature variations of water and air? Water has am much higher heat capacity than ice, soil, or air. Water can store a large amount of energy with only a small temperature change. 6 different phase changes of water Sublimation, melting, evaporation, deposition, condensation, freezing Which phase changes warm the environment? Deposition (water vapor-- ice) Condensation (water vapor-- liquid water) Freezing (liquid water-- ice) Conduction Transfer of heat from molecule to molecule within a substance. Which phase changes cool the environment? Sublimation (ice--water vapor) Melting (ice-- liquid water) Evaporation (liquid water-- water vapor) Convection Transfer of heat by the movement of a fluid. Radiation Process in which energy is emitted as particles or waves Why is conduction not effective in the atmosphere? Air is not a good conductor How does convection work? Warm air rises, cold air sinks Warm less dense air rises, as air rises it expands and cools. Cold more dense air sinks, as air sinks it compresses and warms. What is the Stefan-Boltzmann law? As the temperature of an object increases, it emits more radiation. What is the Greenhouse Effect? Process by which gases in the atmosphere insulate the surface. How is the Greenhouse effect beneficial to us? It is necessary for most life on Earth. Without it, surface temperature would be 33k lower. How is the Greenhouse effect harmful to us? (Enhanced Greenhouse Effect) They cause climate change by trapping heat, and they also contribute to respiratory disease from smog and air pollution Earth's surface temperature vs. radiative equilibrium temperature: Why are they different? Earth's radiative equilibrium temperature is 33k lower than its average surface temperature. What causes Aurora? Solar wind disturbs the Earth's magnetic field Where (location and altitude) does Aurora tend to be observed? Mostly seen at polar latitudes. Occur in Thermosphere no lower than 80 km. (Average 105 km) Why does Earth have seasons? Because its axis is tilted as it revolves around the sun Geographic variations in daylight hours Angle and amount of daylight largely governed by the Earth's 23.5 degree tilt. Why is it still warmer in Northern Hemisphere (NH) summer in places like New York or Chicago than in Alaska, despite Alaska receiving more sunlight? Most sunlight near the poles gets scattered moving through a thicker layer of atmosphere. Why is the Southern Hemisphere (SH) climate less extreme than the NH climate? SH (81%) has more water than NH (61%) Maximum solar radiation in the NH is June 21st, but maximum temperature occurs in July/August. Why? Time lag of seasonal maximum and minimum temperatures Why is there a time lag in daily maximum and minimum temperature? Sun is overhead at noon. Maximum temperature occurs around 3 p.m. Because temperature peaks when incoming and outgoing radiation are in balance. Which weather conditions favor radiational cooling and inversions at night? Calm, clear, dry nights rather than windy nights. Understand the relationship between location and daily temperature ranges Daytona Beach typically has a smaller daily range than Kansas City. Why? Why do some locations have similar average annual temps, but very different seasonal climates? San Francisco and Washington DC have similar average annual temperatures What is the definition of "normal"? 30 year average of temperatures for a specific date Wind chill How cold we feel when combining the actual temperature and the effect of the wind. Wind chill calculate Stronger wind = larger difference between temperature and wind chill Heat index A measure of how warm we feel. Heat index calculate Higher humidity = larger difference between heat index and temperature. Why does an object appear a certain color to our eyes? All visible light that hits our eyes is interpreted by nerve endings in the retina. Rods and cones. Absorbs all wavelengths except that color you see. What makes white clouds have its color? Clouds appear white because cloud droplets scatter all visible wavelengths equally. What makes blue skies have its color?