The lesson essential questions that will guide our investigations are:

Transcription

1 Properties of the Atmosphere: Understanding Patterns Through Observation and Data Collection that Lead to Prediction of Local and Global Weather and Climate. Up until this point in class you have learned how uneven heating of the Earth s surface leads to changes in moisture content and pressure in the air. You have learned about how density changes leads to changes in pressure, which in turn can cause regions of high and low pressure that result in Global, Regional and Local winds. You have learned how temperature and moisture content of air changes over the surface of the Earth that lead to the creation of air masses with different properties and that the boundaries between these air masses can be classified as different types of fronts. You have learned how to recognize these patterns on surface weather maps. In the next phase of the Weather and Climate Unit we will look at how data on different properties of the atmosphere are collected and recorded and how these data can be used to recognize patterns that can be used to make predictions. You will use what you have learned in the first part of the unit to make predictions about the structure of the atmosphere and how global wind patterns move weather systems across the United States. You will learn how surface data is collected and recorded and will combine that knowledge with what we have learned about air masses and pressure to make predictions about future weather. We will end the unit by applying what we have learned to analyze global climate patterns. The lesson essential questions that will guide our investigations are: LEQ: What properties does the atmosphere have that can be observed, measured, and how can they be used to predict changes in weather and to identify climatic patterns? LEQ: How are global weather data from ground measurements, satellites and radar recorded on maps? LEQ: How are global weather data analyzed, and used to predict local weather?

2 Name pd Date Check for Understanding: Properties of the Atmosphere 1. Using only two words what do you think the main objective of the next phase of the weather unit is? 2. Describe three things we have already studied in the weather unit. 3. List three things we will be studying in the next phase of the unit. 4. What questions do you have as we begin the final stage of the weather unit?

3 Structure of the atmosphere: The Earth s atmosphere is made mainly of nitrogen and oxygen. By volume it is about 78% nitrogen gas (N 2 ) and 21% oxygen gas (O 2 ) the remaining 1% is all the other gasses that make up the air including Carbon Dioxide (CO 2 ), water vapor (H 2 O), argon gas(ar), Methane (CH 4 ) among others. There is a structure to atmosphere based on changes in temperature. There are 5 main layers. Most of the mass of the atmosphere is in the layer closest to the surface called the Troposphere. It extends from the surface up to an average of 7 miles. As you go up from the surface through the troposphere the temperature decreases to about -75 F! This is about the altitude that commercial airlines fly. From 7 miles to 30 miles is the Stratosphere. This is the layer that has what we call the Ozone Layer. Ozone (O 3 ) is a gas that absorbs Ultra Violet energy. The temperature increases as you move up through the stratosphere to about 0 F. All of weather occurs in the troposphere and lower stratosphere. At this altitude 99% of the mass of the atmosphere is below you! Extending from about 30 to 50 miles from the surface is the Mesosphere, in this region the temperature begins to decrease again and falls to around -100 F. The mesosphere is the part of the atmosphere where meteoroids burn up. While the density in this region is incredibly low, there is still enough material for friction to cause high speed particles from space to heat up, the result of this is what you see as a shooting star a meteor. As the trip upward through the atmosphere continues from 50 to 100 miles away from the surface is the Thermosphere. As you move up through the thermosphere the temperature increases dramatically depending on solar activity the temperature in this region varies between F! The upper thermosphere is called the Exosphere and it extends into the 1000 s of miles into space. The lower exosphere is where satellites and the space station orbit. We know of the temperature, density, pressure, and composition changes because weather balloons and rockets send instruments called radiosondes and rawinsondes up through the atmosphere that record this information. The radiosondes from weather balloons can be regularly recovered this data and the rawinsonde data from rocket launches is transmitted to the National Weather Service and National Oceanic and Atmospheric Administration. This information combined with data collected at surface stations all over the country and data from weather satellites allows meteorologists to observe patterns and make predictions based upon those patterns.

4 Name pd Date Apply what you have learned: Structure of the Atmosphere 1. If most of the mass of the atmosphere is in the troposphere, what can we predict about the air pressure? 2. Since the temperature decreases as you go up through the atmosphere, what can you predict about the air pressure as you go up? What about amount of water vapor the higher you go? 3. Why would the temperature increase as you go up through the stratosphere? 4. The exosphere is part of the thermosphere, the temperature in this region can reach 1000 s of degrees F. If this is true, how can satellites and the space station orbit here and not be affected by the extreme temperatures? 5. What kinds of tools and instruments are used to collect data on the properties of the atmosphere used to forecast weather?

5 Name pd Date Properties of the atmosphere that are used to understand weather and climate patterns. Use the space below to record the definition, instrument used to collect data and significance of the following atmospheric properties that are observed at surface weather stations. Air Temperature Weather conditions Dew Point Temperature Cloud Cover Air Pressure Wind Direction Wind Speed

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7 Surface station data: NOAA maintains and operates 1500 surface weather stations and coordinated thousands of volunteer stations. A single, individual station records what the conditions are like at one place at a certain time. One single data point is not very useful in detecting patterns, but combining data at one station with thousands of others gives a powerful tool for recognizing and recording patterns. Analyzing these patterns over time allows us to make predictions for the future. Data on certain properties of the atmosphere for a surface station are recorded on maps using a coded symbol called a station model, sometimes referred to as station circles. They work like this Data on NWS Surface Station Model (Circle) Air Temperature Weather conditions Dew Point Temperature Cloud Cover Air Pressure Wind Direction Wind Speed Station Model Guide Sheet (also called Station Circles)

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9 Cloud Cover Current Conditions have their Own Code The Wind Barb The flag pole gives the wind direction, the flags give the wind speed Calm Variable winds less than 5 mph 5 mph 10 mph 15 mph 20 mph 50 mph 65 mph

10 To figure out the air pressure at a station from the station model To go from data to station model If the data table said the pressure was995.0 mb If the data table said the pressure was mb