Regents Earth Science Unit 7: Meteorology and Atmospheric Energy Name: Meteorology and Atmospheric Energy: Guided Reading I. Temperature and Heat Energy from the sun drives the weather and is essential to almost all life on Earth. Heat energy enters and moves through the atmosphere in three different ways radiation, conduction and convection. Energy from the Sun reaches the Earth through radiation. Radiation is the emission or giving off of energy in the form of electromagnetic energy. Conduction is the transfer of heat by contact from one atom to another atom usually within solids, because the atoms are closely packed. Convection is the transfer of heat energy by circular movements in liquid or gas that results from differences in density. Although heat and temperature are related, they are not the same. The atoms or molecules that make up any substance, even a solid, are in constant motion. The faster the atoms are moving, the greater their kinetic energy, or energy in motion. The temperature of a substance is a measure of the average kinetic energy of the atoms or molecules in that substance. Heat is the total kinetic energy of all of the particles of the substance. QUESTIONS: Refer to the picture above for questions 1-4. 1. What form of heat energy is being represented by the arrows in the water? 2. What form of heat energy is being represented by the flames making contact with the surface of the pot? 3. If you tried to grab the pot handle, what form of heat energy is being represented by the heat you feel on the handle? 4. If you were to put your hand next to the pot (not touching it) what form of heat energy is being represented? 5. Define potential energy Meteorology- Guided Reading 1
II. Characteristics of Water Water is a unique substance because it commonly exists in all three stages of matter. Depending on the temperature water can be - A solid at 0 C or less - A liquid between 0 C and 100 C - Water vapor(an invisible gas) at 100 C or greater Water can change state based on the conditions of the atmosphere. Freezing, melting, sublimation, evaporation, and condensation are all examples of water changing state. When water changes state energy is either absorbed or released. The change in state from water vapor to liquid water is called condensation. Dew and frost both form as a result of condensation. When air cools through direct contact with a cold surface, water vapor condenses directly on that surface, if the air temperature is above 0 C dew forms. If the air temperature is below 0 C frost will form. The change in state from liquid water to water vapor is called evaporation. Sublimation is the change from a solid directly to a gas (water vapor). The actual amount of water vapor in the air at a given time and place is called the specific humidity. There is a limit to the amount of water vapor that can be present in the air. When there is so much water vapor in the air that the rate of condensation equals the rate of evaporation, the air is saturated. The amount of water vapor present in saturated air depends on the temperature of the air. The warmer the air, the more water vapor it can contain. Relative humidity is the term used to describe how near the air is to its maximum capacity for holding water. Relative humidity is expressed as a percent. It compares the actual amount of water vapor in the air with the maximum amount of water vapor the can be present in the air at a given temperature and pressure. Saturated air has a relative humidity of 100%. Relative humidity is measured using a psychrometer. The temperature at which saturation occurs and condensation begins is called the dew point. The dew point is a measure of the amount of water vapor in the air. The more water vapor the air contains, the less the air has to cool in order for condensation to start, so the higher the dew point. Two conditions are necessary for water vapor to condense: (1) there must be material for water vapor to condense onto and (2) air must cool to or below its dew point. Condensation nuclei are tiny particles that water vapor need for condensation to occur. QUESTIONS: 1. Define deposition Meteorology- Guided Reading 2
2. Define latent heat 3. Define heat of fusion Using your ESRT answer the following questions -How much energy is gained during melting? -How much energy is lost during freezing? -How much energy is gained during evaporation? -How much energy is lost during condensation? 4. Define heat of vaporization 5. Define specific heat 6. How does dew form? 7. How does frost form? III. Meteorology and Weather Meteorology is the scientific study of the Earth s atmosphere, especially its patterns of climate and weather. Meteorology helps makes our weather predictions possible. Weather is the state of the atmosphere regarding wind, moisture, temperature, cloud coverage, pressure and other meteorological conditions for a short period of time. In order to predict the weather meteorologists need to know how air masses form and what type of weather is associated with each air mass. An air mass is a large body of air that has the same Meteorology- Guided Reading 3
temperature, pressure and moisture conditions throughout. An air mass is named for where it originates, this is called the source region. The temperature of each type of air mass depends on whether the air mass originated in an arctic, polar or tropical region. The humidity depends on whether the air mass comes from land (continental) or sea (maritime). For example if an air mass originated in Central Canada it would be considered a continental polar (cp) air mass. The air associated with this air mass is cold, because it came from the north and dry, because it formed over land. Air masses are constantly moving across the surface of the Earth, the boundary that separates the two air masses is called a front. The weather associated with a particular front depends on the types of air masses involved and the speed at which they are moving. There are four kinds of fronts: cold, warm, occluded, and stationary. QUESTIONS: 1. Define weather 2. What is the difference between climate and weather? 3. What is a source region? 4. What is a front? 5. An air mass that formed over the Gulf of Mexico would be named a air mass. IV. Air Pressure and Wind The weight of the atmosphere as it pushes down upon Earth s surface exerts a force per unit of area is called air pressure. Air pressure is measured using a barometer. There are two types of barometers mercury and aneroid. A mercury barometer measures air pressure in inches of mercury while an aneroid barometer measures air pressure in millibars. Elevation, temperature and humidity are all factors that affect air pressure. Changes in air pressure help us predict the weather. A decrease in air pressure signals the approach of warmer, more humid air while an increase in air pressure often signals the arrival of cooler, drier air. When plotted on a weather map, lines that connect points of equal air pressure are called isobars. A closed isobar is one that forms a closed loop on a weather map. If the air pressure steadily increase toward the center of a set of closed isobars this is defined as a high pressure system (anticyclone). If the air pressure steadily decreases toward the center of a set of closed isobars this is defined as a low pressure system (cyclone). Dividing the pressure change by the distance over which the pressure changes yields the pressure gradient. Pressure differences and wind is caused by unequal heating of Earth s surface. Wind blows from areas of high to low pressure and their speeds are measured using an instrument called an anemometer. The diagrams show the differences between a sea breeze and a land breeze. A sea breeze occurs because Meteorology- Guided Reading 4
during the day the land heats up faster than the water resulting in warm, less dense air rising over the land. This creates an area of low pressure over the land. Over the water cooler, more dense air sinks and creates an area of high pressure. When then blows from high to low pressure or from the sea to the land. A land breeze occurs because at night the water retains heat better than the land. This results in warm, less dense air now rising over the sea creating an area of low pressure. Over the land cooler, more dense air is sinking creating an area of high pressure. Wind then blows from high to low pressure or from the land to the sea. If the Earth stood still and did not rotate, Earth s winds would move in a straight line from areas of high pressure to low pressure. Since the Earth is constantly rotating we experience the Coriolis Effect. The Coriolis Effect is the tendency of an object moving freely over Earth s surface to curve away from its path of travel. In the Northern hemisphere objects will curve to the right while in the Southern hemisphere objects will curve to the left. Because of the Coriolis Effect winds in the Northern hemisphere tend to blow clockwise out of areas of high pressure and counterclockwise into areas of low pressure. QUESTIONS: 1. Why does water heat up and cool down slower than land? 2. A hurricane can be associated with which type of pressure system? Meteorology- Guided Reading 5
Regents Questions: Use your ESRT and this reading packet to answer the following multiple choice questions. The graph shows the results of heating 10 grams of water from 100 C to +200 C. The same amount of heat was added during each minute. 1. What is the most probable explanation for the constant temperature between points D and E on the graph? 1. The added heat was radiated as fast as it was absorbed. 2. The added heat was lost to the surroundings. 3. The added heat changed liquid water to water vapor. 4. The added heat changed water vapor to liquid water. 2. Approximately how long did it take to completely change the 10 grams of water from a solid at 100 C to a gas at +100 C? 1. 1 minute 2. 5 minutes 3. 11 minutes 4. 15 minutes 3. During which time interval was the rate of temperature change the greatest? 1. A to B 2. B to C 3. C to D 4. D to E 4. In which phase does water have its highest specific heat? 1. solid 2. liquid 3. gas Meteorology- Guided Reading 6
The diagram shows a container of water that is being heated. 5. The movement of water shown by the arrows is most likely caused by 1. density differences 2. insolation 3. the Coriolis effect 4. the Earth s rotation 6. Which process requires the addition of energy to water? 1. freezing of water 2. cooling of water 3. vaporization of water 4. condensation of water The diagram shows equal masses of four different earth materials at different temperatures. 7. Which statement best describes the relationship between a heat sink and a heat source if the samples are placed in contact with each other? 1. The water will be a heat sink for the iron. 2. The iron will be a heat sink for the granite. 3. The granite will be a heat source for the dry air. 4. The dry air will be a heat source for the water. Meteorology- Guided Reading 7
8. Convection currents may be produced most easily in the samples of 1. water and dry air 2. water and granite 3. granite and iron 4. iron and dry air 9. During winter, Lake Ontario is generally warmer than adjacent land areas. The primary reason for this temperature difference is that 1. water has a higher specific heat than land has 2. water reflects sunlight better than land does 3. land is more dense than water is 4. winds blow from land areas toward the water The diagram represents a large beaker of water being heated to demonstrate convection. 10. The movement of water upward from A toward B results primarily from 1. differences in density in the water 2. air movement across the surface of the water 3. capillary action within the water 4. the shape of the beaker Meteorology- Guided Reading 8
11. Which graph best represents the relationship between the moisture-holding capacity (ability to hold moisture) of the atmosphere and atmospheric temperature? 1. 3. 2. 4. 12. Which abbreviation indicates a warm air mass that contains large amounts of water vapor? 1. cp 2. ct 3. mt 4. mp 13. In the Northern Hemisphere, what is the direction of surface wind circulation in a high-pressure system? 1. clockwise and outward from the center 2. clockwise and toward the center 3. counterclockwise and outward from the center 4. counterclockwise and toward the center 14. Which symbol would be used to identify an air mass originating in central Canada? 1. mt 2. mp 3. ct 4. cp Meteorology- Guided Reading 9
The map shows North American air mass source regions, the resulting air-mass names, and typical airmass tracks. 15. A maritime polar air mass approaching New England would most likely bring 1. cool, moist air from the north 2. warm, moist air from the south 3. cool, dry air from the southeast 4. warm, dry air from the southwest 16. Polar air-mass characteristics differ from tropical air-mass characteristics primarily because the source regions differ in 1. nearness to land 2. nearness to water 3. latitude 4. longitude Meteorology- Guided Reading 10