GEOG 111 1st Edition Exam 1 Study Guide Lectures 1 10 Each test will consist of 40 multiple choice questions that are drawn from the lecture material weather quizzes and in class weather discussions These questions will be answered on a scantron sheet which can be obtained from the bookstore from Geography 111 syllabus Lecture 1 August 22 Lecture 2 August 25 Introduction to weather forecasts Types of Forecasts o Quantitative forecast a value for the forecast variable is provided i e an inch of rain is expected o Qualitative forecast provided only categorical value for the predicted variable i e rain or no rain o Probability forecast the chance of some event is stated 3 resources in making forecast o Weather models computers that use physics to simulate atmospheric conditions of the future o Climatology tell what conditions you would normally expect Usually a good starting point for weather forecasters and may indicate that a weather model needs to be tuned o Forecaster knowledge something to keep in mind when reading forecasts Pattern recognition experienced forecasters in an area can recognize patterns and question models Elements of a forecast o Low high temperature o Heat index what it actually feels like outside includes humidity o Precipitation probability of measureable precipitation o Wind speed pertains to open landscapes o Wind direction the direction winds are blowing from Important in air travel and hurricane prediction Forecasting skill o Accuracy depends on Proximity to forecasting location Size of the region How well the forecaster knows the climatology and recognizes its patterns o Weather models accuracy decrease with time Should be trusted 3 5 days into the future but after that it s better to rely on climatology Lecture 2 August 25 Lecture 3 August 27 Solar and Terrestrial Radiation Radiation comes in many forms through the electromagnetic spectrum o Discriminated on the basis of wave length gamma xrays UV visible light infrared radiation microwaves radio waves Short end powerful gamma rays that can go through solid materials Long end microwaves and radio waves that have long wavelengths and are far less powerful Radiation Laws o Stefan Boltzmann Law the hotter a body is the more radiation it emits Blue is shorter part of the wavelength so it s the hottest part of the flame E Stefan Boltzmann constant temperature 4 o Weins Law the wavelength of maximum emission The sun peaks at a shorter wavelength than the Earth which ensures that it s hotter Temperatures generally decrease with increasing height above the earth therefore higher clouds are colder than lower clouds and the earth Solar Output relatively constant over time o Sunspots storms on the surface of the sun o More sunspots more solar radiation higher temp on Earth s surface Earth atmosphere radiation processes Absorption to assimilate or take in energy The atmosphere absorbs some of the radiation from the sun Example Greenhouse gases such as CO2 and water vapor that are very effective in absorbing infrared long wave radiation emitted from the Earth s surface This warms the atmosphere up and reradiates more energy back to the surface Reflection the temperature of the reflecting object is unchanged Albedo A describes the overall reflectivity of the Earth s surface o A outgoing K incoming K x 100 o Where K is reflected radiation o Light colors have high albedos and dark colors have low albedos Scattering redirecting part of the visible light spectrum As visible light comes into the atmosphere blue light is cycling rapidly and reds are cycling slowly Blues are more likely to collide with an atmospheric particles and be redirected scattered so blue light is preferential the sky is blue in an average midday sky o The color of the sky indicates the amount of scattering taking place Increased volcanic dust increases possibility that warm colors will scatter Solar radiation can be partitioned into two components o Direct beam divided into light and dark directly from the sun when clouds block direct beam they create shadows o Diffuse light sky light from diffused radiation Inverse relationship between direct beam and diffuse Less scattering high direct beam low diffused light dark blue sky More scattering low direct beam high diffused light lighter blue sky Three controlling factors of atmospheric transmissivity the ease with which radiation is transmitted through the atmosphere can be visible light or infrared radiation from the Earth Clouds no direct beam all diffuse Haze microscopic particles aerosols in the sky direct beam decreases diffused light increases Elevation atmosphere is thinner at higher altitudes so less light gets scattered and the sky is a darker blue direct beam increases diffused light decreases Lecture 4 August 29 Lecture 5 September 3 Earth Sun Geometry Seasonal changes in earth sun geometry controls the intensity of solar radiation and the length of the day Two independent motions affect earth sun geometry o Rotation counterclockwise West to East goes 360 degrees in 24 hours This is why we have time zones We go later in time to the east Europe is ahead of us and earlier in time to the west The sun rises and sets later on the western edge of a time zone region and earlier on the eastern edge of a time zone region o Revolution the earth revolving around the sun on the plane of the ecliptic Takes 365 25 days Due to the earth s elliptical path not a perfect circle the distance between the earth and sun varies during the year Perihelion around January 3 Earth is closest to the sun 147 500 000 km Aphelion around July 4 Earth is farthest away from sun 152 500 000 km The Earth s axis is tilted 23 5 degrees with respect to the plane of the ecliptic o This results in seasons Solstice December 21 22 June 21 22 Summer longest day in Northern Hemisphere SE maxed out in NH SD 23 5 degrees north Tropic of Cancer Latitude increases day length increases Winter shortest day in NH SE min in NH SD 23 5 degrees south Tropic of Capricorn Latitude increases day length decreases Equinox March 21 22 September 22 23 At noon the sun will be hitting the equator directly overhead Equal day and equal night everywhere 12 hours SD 0 degrees Equator Solar declination SD latitude at which the sun s direct rays are hitting Always between 23 5 degrees north Tropic of Cancer to 23 5 degrees south Tropic of Capricorn Solar elevation SE the sun s position in the sky Highest in June Seasonal changes in the length of the day are