Survey
* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
Weather and Climate Content Goal 3: The learner will conduct investigations and use appropriate technology to build an understanding of weather and climate. Alex Richardson Elementary Science Coach arichard@wsfcs.k12.nc.us 1 Background Concepts Three big factors influence weather and climate worldwide: the Sun, the water cycle, and the atmosphere. The Sun is perhaps the largest influence on our planet’s weather and climate. Climate is determined by the amount of sunlight a location receives. 2 Changes in the Sun’s intensity through time as well as changes in the amount of sunlight let into the Earth system can drastically affect our world. 3 The Earth is surrounded by five layers of the atmosphere. Exosphere Thermosphere Mesosphere Stratosphere Troposphere 4 Troposphere Lowest layer closest to the Earth Nearly 75% of the gases in the atmosphere are contained in this layer. Temperatures generally decrease with altitude. 5 Troposphere (cont’d) Extends outward about 7-10 miles (11to16 kilometers) Clouds form Most weather happens here. 6 Stratosphere Lies above the troposphere extending to about 31 miles (50 kilometers) Contains the ozone layer, which protects life on Earth from the Sun’s harmful ultraviolet radiation Molecules of ozone absorb the radiation 7 Stratosphere (cont’d) Temperatures can increase with altitude if this layer is damaged by ozone. Air pressure is lower than troposphere. Jets cruise near the bottom of this layer. 8 Mesosphere Lies above the stratosphere Extends from the top of stratosphere to an altitude of about 50 miles (80 kilometers) This is the coldest layer of the atmosphere. 9 Mesosphere (cont’d) Temperature goes down as altitude increases. Meteors, or “shooting stars” burn up here. Air pressure is lower than stratosphere. 10 Thermosphere Lies above the mesosphere and extends to outer space (90 km to 300 km) Temperatures are extremely high as altitude increases. Air pressure is lower than mesosphere 11 Thermosphere (cont’d) Despite high temperatures, the air would feel cold. Contains few molecules of air Molecules rarely collide and thus cannot transfer energy. 12 Exosphere Extends (300 km to more than 600 km) Air pressure is lowest in this layer. Temperature increases as altitude increases. Many satellites orbit here. 13 Objective: 3.01 Investigate the water cycle including the processes of evaporation, condensation, precipitation, and run-off. The water cycle is one of Earth’s cycles that sustains life. The sun is the primary energy source that powers the water cycle. The water cycle is a vital component in the creation of weather and climate. The cycling of water is composed of several different phases that include evaporation, condensation, precipitation, and run-off. 14 Components of the Water Cycle Water Storage in Oceans Water Storage in Ice and Snow Snowmelt Runoff to Streams Water in the Atmosphere Evaporation Sublimation Springs Infiltration Surface Runoff Freshwater Storage GroundWater Storage Ground-Water Discharge Condensatio Precipitation Streamflow Evapotranspiration n 15 Water on Earth is evaporated into the air where it condenses and falls back to the Earth as: Liquid Precipitation Frozen Precipitation Mixed Precipitation 16 Evaporation The change of a liquid into gas or vapor Heat from the Sun changes surface water from a liquid to water vapor, which then enters the atmosphere. Substances dissolved in the water, such as salt, are left behind. 17 Condensation Occurs when water vapor in the atmosphere cools and changes to liquid water Water vapor droplets in the atmosphere become large and heavy eventually falling to the ground. The water falls to Earth as precipitation. 18 Precipitation Precipitation occurs when clouds loose water. Solid or liquid moisture falling from the sky is precipitation. Water that moves from the atmosphere to the land in the form of rain, snow, sleet, or hail The type of precipitation depends on the temperature of the air that the water falls through. 19 Precipitation (cont.) Air above freezing-precipitation will most likely be rain. Air below freezing-precipitation will most likely be snow. Different temperature layers exist within the air. If snow falling from a high cloud passes through a warmer layer-snow could melt into rain. 20 Precipitation (cont.) If rain passes through another layer that’s colder near the ground-it becomes sleet. Hail is also the result of water passing through different temperature layers. Water can be found in all three states-solid, liquid and gas-- at normal temperatures and pressures. 21 Runoff Runoff is all the remaining water that moves over the Earth’s surface. The force of a falling raindrop can loosen and pick up soil particles. As water moves over land, it carries particles with it. Because of gravity, runoff and the material it contains move downhill. 22 Objective: 3.02 Discuss and determine how the following are affected by predictable patterns of weather: Temperature, Wind direction and speed, Precipitation, Cloud cover, and Air pressure. Climate is predictable patterns of weather over time. Climate refers to the long-term weather patterns for a given area. Climates can experience long-term and short-term changes. Short-term changes include seasons, caused by Earth’s tilted axis and El Niño. El Niño is caused by periodic temperature changes in the southern Pacific Ocean, resulting in extreme weather from flooding to drought. 23 Weather Concepts Weather depends on the elements of temperature, air pressure, wind, and moisture. Weather is not random. Weather occurs in predictable patterns. The degree of heating and cooling of the Earth’s surface is a result of interactions of various atmospheric factors to influence different patterns of weather. 24 Factors Affecting Climate Latitude, the distance north or south of the equator, influences climate mainly. Proximity of large bodies of water Altitude The presence of mountains 25 World Climate Zones Affecting Climate Tropical Zones Temperate Zones Polar Zones 26 World Climate Zones Tropical Zones • Located between 23.5° north and south of the equator • Receive direct or nearly direct sunlight year round • Have temperatures that are warm year-round 27 World Climate Zones (cont’d) Temperate Zones Located between 23.5° and 66.5° north and south of the equator Receive the sun’s rays more directly in the summer; In winter, the sun’s rays strike at a lower angle. Weather ranges from warm or hot in the summer to cool or cold in the winter. 28 World Climate Zones (cont’d) Polar Zones Located from 66.5° north and south of the equator to the poles Receive little direct sunlight since the sun’s rays strike at a lower angle near the poles Areas near both poles have cold climates. 29 Temperature Concepts Temperature indicates the relative warmth or coolness of a substance as measured by thermometers. Temperature is measured in degrees. Most people in the United States measure temperature using the Fahrenheit scale. The Celsius scale is commonly used to measure temperature in other parts of the world. 30 Temperature Concepts (cont.) The Fahrenheit scale was named after Gabriel D. Fahrenheit from Germany who lived from 1686 to 1735. He devised a way of measuring temperature. He put mercury inside a glass tube and marked 180 degrees between the freezing and boiling points of water. His scale goes from 32 to 212 degrees Anders Celsius, from Sweden, developed the temperature scales most often used today. Celsius marked 100 degrees between the freezing and boiling points of water. His scale goes from 0 to 100 degrees. 31 Wind Concepts Wind is air in motion caused by uneven heating. Wind is caused by air moving from an area of high pressure to one of low pressure. The greater the distance between the areas, the stronger the wind. 32 Wind Concepts (cont’d) Winds are named for the direction from which the wind blows. Wind usually blows from the same direction. There is a general pattern to air circulation on Earth since the equator is constantly hot and the poles are cold. 33 Please review Science Objective 3.01 for previous precipitation concepts. Review slides 19, 20, and 21 for precipitation content. 34 Cloud Cover Concepts Cloud cover is the amount of sky covered by clouds. Clouds are formed when air containing water vapor starts to condense into droplets of moisture. Cloudiness or cloud cover is one of the variables of climate. There are different types of clouds that may cover all or parts of the sky. 35 Cloud Cover Concepts (cont’d) The amount of cloud cover is determined by estimating the percentage of the sky covered with clouds. Clear (0% - 5%) Partly Cloudy (5% - 50%) Mostly Cloudy (50% - 95%) Overcast (95% - 100%) 36 Air Pressure Concepts Air pressure is the weight of air particles pressing down on the surface of the Earth. Air pressure may be high or low. Air pressure lessens as you move higher up in the atmosphere The higher you are, the less air is above you. Less air is pushing down on you, so the air pressure is lower. Air temperature affects air pressure. 37 Air Pressure (cont.) A high pressure system is associated with cooler temperatures and clear skies. A high pressure system forms where cool air sinks. A low pressure system is associated with warmer weather, storms, or precipitation. An instrument called a barometer measures air pressure. 38 Air Pressure (cont.) Air pressure is often stated in inches of mercury since we measure the height of mercury in the tube in inches. Normal air pressure readings vary from 29 to 31. Quick changes in air pressure often mean a change in weather is about to occur. You’ll often hear or read about Barometric pressure during local weather reports because of quick changes in air pressure. 39 Objective 3.03: Describe and analyze the formation of various types of clouds and discuss their relation to weather systems. Clouds are made of tiny vapors of water. A cloud is the result of invisible water vapor in the air becoming visible. Visible water vapor in the air is clouds; visible water vapor near the Earth is fog or mist. There are different types of clouds which signal different kinds of information about the weather. 40 Three basic types of clouds form in the skies: Cirrus Cumulus Stratus 41 Different Types of Clouds Cirrus Stratus In Latin, cirrus means curl Latin word for layer or blanket Feathery-like plumes and wispy Low altitude clouds (below 10,000 feet) Very high in the atmosphere where the air is very cold (over 20,000 ft) Form a layer that can cover the entire sky like a blanket Rain and drizzle associated Clouds of ice crystals usually associated with fair weather, but may sometimes indicate that storms are on the way If they lift quickly in the morning, they often mean a fine day ahead 42 Different Types of Clouds (cont.) Cumulus Latin for heap (low cloudsunder 10,000 feet) Usually associated with fair weather Can produce precipitation if they are very tall Dense, white puffy, cotton like, thick When large and bunched, they can cause heavy showers Cumulonimbus Usually suggest bad weather conditions Huge, grey, and towering clouds up to 60,000 feet Can bring rain, sleet, hail, thunder, lightning, and tornadoes The top of the cloud is often anvil-shaped 43 Different Types of Clouds (cont.) Nimbostratus Low dark sheets of clouds under 10,000 feet Blot out the sun Often followed by lengthy precipitation within a few hours Stratocumulus Low rolling mass of clouds under 10,000 feet Thin lumpy gray to white clouds May produce light precipitation that usually dissipates by the end of the day 44 Different Types of Clouds (cont.) Altocumulus Larger than cirrocumulus clouds Middle clouds between 10,000 to 20,000 feet Patterned white to gray clouds that are often rippled or appear in waves Considered fair weather that often follow storms Altostratus Formless gray to bluish clouds Middle clouds between 10,000 to 20,000 feet Form a thin veil over the sun and moon If these clouds gradually darken and blot out the sun or moon, precipitation will follow 45 Different Types of Clouds (cont.) Cirrostratus High clouds over 20,000 feet Milky, white-veined clouds Produce a halo around the sun or moon Often called “bed-sheet clouds If clouds are replaced by cirrostratus clouds it usually means precipitation will follow Cirrocumulus High clouds over 20,000 feet Appear in layers that look like rippled sand or fish scales Nicknamed “mackerel sky” Considered an omen of good weather 46 Different Types of Clouds (cont.) Contrail Thin high altitude clouds over 20,000 feet Formed when moisture released from jet engines turns into ice crystals Swelling Cumulus Flat bottomed towering clouds up to 60,000 feet Have growing, cauliflower-like towers Often form in midday and precede cumulonimbus clouds 47 Visual Opacity The thickness of a cloud determines the amount of light being transmitted through the cloud. Visual opacity can be described as: Opaque Translucent Transparent 48 Objective 3.04 Explain how global atmospheric patterns affect local weather When cool and warm air collide, wind is created. The collision causes warm air to rise. When air rises it gets cooler. Cooler air causes the water vapors in the atmosphere to condense or form water droplets. Cool air can not hold as much moisture as warm air. 49 Global Atmospheric Patterns (cont.) There are many types of wind patterns that affect global weather patterns. The wind pattern that affects our state are the Prevailing Westerlies named so because they blow in from the west. The Prevailing Westerlies move weather from west to east. Weather in your area may be different from weather in another part of the state or country. 50 Four Major Types of Air Masses Influence Weather in North America Cold and Dry Hot and Dry Cool and moist Warm and Moist 51 Cold and Dry Air Masses Continental Polar air masses bring cool or cold air in winter. Form over central and northern Canada and Alaska Air masses that form near the Arctic Circle can bring bitterly cold weather with very low humidity. 52 Hot and Dry Air Masses Continental Tropical air masses form only in summer over dry areas of the Southwest and northern Mexico. Cover a smaller area than other air masses. Occasionally move northeast, bringing hot dry weather to the southern Great Plains. 53 Cool and Moist Air Masses Maritime Polar air masses form over the icy cold North Pacific and North America. They affect the West Coast more than the East Coast. These air masses usually bring fog, rain, and cool temperatures to the West Coast. 54 Warm and Moist Air Masses Maritime Tropical air masses form over oceans near the tropics. When these air masses form over the Gulf of Mexico and the Atlantic Ocean, they move first into the southeastern United States. Then these air masses then move north and northeast, where they influence weather in the central and eastern United States. Hot humid weather is usually associated with maritime tropical air masses in the summer. 55 Fronts A front is an area where the air masses meet and do not mix. Two air masses meet with different temperatures and densities. When air masses meet at a front, the collision often causes storms and changeable weather. 56 Four Types of Fronts Cold Fronts Warm Fronts Stationary Fronts Occluded Fronts 57 Cold Fronts Cold fronts move quickly, so they can cause abrupt weather changes including violent storms. Cool dry air moves in an area after a cold front passes through. Cold air is dense and tends to sink. Denser cold air slides under the lighter warm air. 58 Warm Fronts Clouds, storms, and rain also accompany warm fronts. If warm air is humid, showers and light rain fall along the front where warm and cold meet. Warm fronts move more slowly than cold fronts. In winter, warm fronts bring snow. 59 Stationary Fronts A front is stationary when a warm front and a cold front doesn’t have enough force to move the other. If a stationary front remains stalled over an area, it may bring many days of clouds and precipitation. When the warm and cold air meet, water vapor in the warm air condenses into rain, snow, fog, or clouds. 60 Occluded Fronts At an occluded front, a warm air mass is caught between two cooler air masses. When a cold air mass and a cool air mass come together, the warm air mass caught between them is forced upward. The result of the mix is an occluded front. The warm air mass is cut off from the ground. As it cools and its water vapor condenses, the weather may turn cloudy and rainy or snowy. 61 Objective 3.05 Compile and use weather data to establish a climate record and reveal any trends. Weather can be observed and information about weather can be collected, measured, recorded, analyzed and presented. Weather information is collected and analyzed using many different tools, techniques, and strategies. (Including maps, charts, computers, satellites, balloons, and storm chasers). Forecasts about weather are made on short range and extended forecasts. Predictions about weather are based on historical climate trends and current data which is updated regularly as more information is received. 62 Tools Used to Collect Weather Data Ordinary radar is able to report location and strength of precipitation. Doppler Radar indicates wind direction, wind speed, and boundaries between warm fronts and cold fronts as well as location and strength of precipitation. Observational tools such as satellites, dropsondes, weather stations, weather buoys, ships, and airplanes are sources of weather data. 63 Weather Data Collection (cont.) Weather stations and buoys record various weather parameters at fixed locations. Ships and airplanes are moving weather stations recording data at their current position. After being launched from balloons or airplanes, 1800 dropsondes collect weather data as they drop through the sky each day. Satellites are important sources of weather data. Data from all these sources are channeled into a supercomputer at a central location to make weather predictions that take into account the current weather. 64 Weather Data Collection (cont.) Supercomputers Use numerical forecasting or mathematical calculations to predict weather Perform many calculations that take into account such as air pressure differences, solar radiation, the Earth’s rotation, the water cycle, as well as current information Allow forecasters to generate more accurate forecasts based on a comprehensive regional perspective about current weather 65 Weather Data Collection Tools Barometer Anemometer Wind Vane Psychrometer Thermometer Rain Gauge 66 Weather Data Collection Tools (cont.) Barometer Measures air pressure Sometimes referred to as barometric pressure The pressure of the air on the pool of mercury causes the mercury to rise in a tube. The height of the mercury in the tube is measured in inches. Anaeroid Barometer Doesn’t contain mercury The air pressure on this box causes it to change shape, moving the needle on the gauge that indicates air pressure. 67 Weather Data Collection Tools (cont.) Anemometer Measures wind speed Wind pushes small cups and makes part of the anemometer spin. The faster the wind blows, the faster the cup spins. Counts how many turns the cups make in a certain time. The dial then shows the wind speed. Wind Vane Shows from which direction the wind is blowing Letters on the wind vane show which way is north, south, east, and west. An arrow turns to point into the wind. If a wind vane’s arrow points north, that means wind is blowing from the north. 68 Weather Data Collection Tools (cont.) Psychrometer Measures relative humidity Often called wet bulb thermometer Uses two thermometers, one bulb of which is covered with a wet cloth. As the cloth dries, the cooling effect of evaporation lowers the temperature on that thermometer Temperatures on the two thermometers are compared on a chart to find relative humidity Thermometer Measures air temperature via the expansion of a liquid or a metal as the air temperature changes Numbers on a thermometer are the scale. The scale shows the temperature in degrees. 69 Weather Data Collection Tools (cont.) Rain Gauge A very simple instrument that collects rain Used to measure the amount of liquid precipitation The average conversion of 10 inches of snow equals 1 inch of rain to find out how much water fell. 70 Objective 3.06 Discuss and determine the influence of geography on weather and climate: mountains, sea breezes, and water bodies Geological features influence weather patterns. Mountains and large bodies of waters such as oceans and huge lakes have the most affect on weather patterns. Wind blowing against a mountain causes the air to rise, cool, and condense. ( cool air can hold less moisture than warm air). Wind that flows over the mountain and down the other side causes air to become warmer and takes up moisture through evaporation. 71 Influence of Geography (cont.) Land absorbs heat from the sun faster than bodies of water; therefore as the warm air of the land rises, it is replaced by the cooler air from the water that we call sea breezes. Urbanization also affects weather conditions such as, it is typically hotter and rainier in large cities than in rural areas; factors contributing to this are: pavement, huge buildings, transportation systems, factories, etc. 72 Influence of Geography (cont.) Geography is influenced by: Mountains Sea Breezes Water Bodies 73 Mountains Humid winds blowing from the ocean toward coastal mountains causes the air to rise up to pass over the mountain. Rising warm air cools and its water vapor condenses forming clouds. Cool air can hold less moisture than warm air. Mountains in the path of prevailing winds can influence where precipitation falls. 74 Mountains (cont’d) Rain or snow falls on the windward side of the mountain, the side oncoming wind hits. Land on the leeward side of the mountain, the downwind, has cool dry air since it has lost much of its water vapor. The leeward side of the mountain forms a rain shadow, an area that doesn’t receive rain, because a mountain range blocks the rain. 75 Sea Breezes A wind that blows from the ocean onto land is a sea breeze. Cool air, during the day, moves from the sea to the land. At night, the situation reverses. Land cools more quickly than water, so the air over land becomes cooler than the air over water. 76 Water Bodies Oceans are the bodies of water most often referred to as the five oceans-Atlantic, Pacific, Arctic, Indian, and Southern. The Atlantic and Pacific oceans are divided by the equator which in turn divides into the North and South Atlantic Ocean and the North and South Pacific Ocean. A sea can be a part of an ocean or attached to an ocean. 77 Water Bodies (cont’d) Water bodies are considered different forms of flowing water. There are many names for water bodies such as: rivers, streams, lakes, bays, seas, oceans, ponds, and etc. The water cycle (hydrologic cycle) plays a very important process which moves all bodies of water, powered by the sun’s energy. 78