Educational Product Educators Grades 5–8 Investigating the Climate System PrecipitationPrecipitation “The Irrational Inquirer” PROBLEM-BASED CLASSROOM MODULES Responding to National Education Standards in: English Language Arts ◆ Geography ◆ Mathematics Science ◆ Social Studies Investigating the Climate System PrecipitationPrecipitation “The Irrational Inquirer” Authored by: CONTENTS Mary Cerullo, Resources in Science Education, South Portland, Maine Grade Levels; Time Required; Objectives; Disciplines Encompassed; Key Terms; Key Concepts . 2 Prepared by: Stacey Rudolph, Senior Science Prerequisite Knowledge . 3 Education Specialist, Institute for Global Environmental Strategies Additional Prerequisite Knowledge and Facts . 5 (IGES), Arlington, Virginia Suggested Reading/Resources . 5 John Theon, Former Program Scientist for NASA TRMM Part 1: How are rainfall rates measured? . 6 Editorial Assistance, Dan Stillman, Truth Revealed after 200 Years of Secrecy! Science Communications Specialist, Pre-Activity; Activity One; Activity Two; Institute for Global Environmental Activity Three; Extensions. 8 Strategies (IGES), Arlington, Virginia Graphic Design by: Part 2: How is the intensity and distribution Susie Duckworth Graphic Design & of rainfall determined? . 9 Illustration, Falls Church, Virginia Airplane Pilot or Movie Critic? Funded by: Activity One; Activity Two. 9 NASA TRMM Grant #NAG5-9641 Part 3: How can you study rain? . 10 Give us your feedback: Foreseeing the Future of Satellites! To provide feedback on the modules Activity One; Activity Two . 10 online, go to: Activity Three; Extensions . 11 https://ehb2.gsfc.nasa.gov/edcats/ educational_product Unit Extensions . 11 and click on “Investigating the Climate System.” Appendix A: Bibliography/Resources . 12 Appendix B: Assessment Rubrics & Answer Keys. 13 NOTE: This module was developed as part of the series “Investigating the Climate Appendix C: National Education Standards. 15 System.”The series includes five modules: Clouds, Energy, Precipitation, Weather, Appendix D: Problem-Based Learning . 17 and Winds. While these materials were developed under one series title, they Appendix E: TRMM Introduction/Instruments . 19 were designed so that each module could be used independently. They can be freely Appendix F: Florida Weather Page . 21 downloaded at: http://www.strategies.org/CLASS.html Appendix G: Cloud Diagram . 22 June 2003 Appendix H: Glossary . 23 1 Investigating the Climate System: PRECIPITATION Investigating the Climate System PrecipitationPrecipitation “The Irrational Inquirer” GRADE LEVELS climatology Grades 5–8 coalesce condensation nuclei/cloud nuclei TIME REQUIRED dew point/humidity graupel Ten to twelve 45-minute class periods hail OBJECTIVES latent heat meteorology ● Students will analyze data and interpret information passive sensor/radiometer in order to make predictions. radar ● Students will utilize satellite data to determine the radiation intensity and distribution of rainfall. rainfall intensity/rainfall rate ● Students will apply satellite data to improve the scientific method safety of air travel. Sun synchronous ● Students will analyze and research global rainfall supercooled water patterns. total integrated rainfall rate ● Students will apply various scientific methods total ozone concentration in order to collect and interpret precipitation turbulence measurements. weather ● Students will apply various scientific methods in order to predict precipitation events. KEY CONCEPTS ● Students will examine long-range weather predic­ ● Clouds that produce thunderstorms, and therefore tions and compare them to archival satellite data. heavy rain and hail, are called cumulonimbus. These ● Students will study scientific data to determine how clouds often span an extremely large temperature rainfall intensity and temperatures change vertically range. In strong thunderstorms, where the updrafts as well as horizontally. exceed 10 m/s, raindrops can actually be lofted up ● Students will investigate the effectiveness of using above the freezing level (where the temperature is the traditional scientific method in meteorological lower than 0°C). Some of these drops freeze to pro­ research. duce ice particles, while others remain in liquid ● Students will use their knowledge of TRMM to pro­ form despite the below-freezing temperatures— pose new instruments and satellite missions, which these are called supercooled water droplets. The will aid us in understanding and predicting changes combination of liquid and ice above the freezing in the Earth’s climate. level is known as the “mixed-phase layer.” In this ● Students will present their ideas to the class. region of the cloud, the ice particles and liquid water drops are colliding with each other. As a liq­ DISCIPLINES ENCOMPASSED uid drop collides with an ice particle, the liquid Meteorology, climatology, geography, language arts, attaches, or accretes, to the ice, enlarging the size of mathematics (data analysis, graphing skills), and the ice particle. Eventually, the ice particle with atmospheric science accreted liquid water (known as graupel) falls out of the updraft either because the updraft is weak­ KEY TERMS ening in that part of the cloud or the particle active sensor becomes too heavy. In some instances where the bright band updraft in the cloud is tilted with height, the parti­ climate cle can actually fall back into the main part of the 2 Investigating the Climate System: PRECIPITATION updraft lower down in the cloud. The particle may Because it is necessary to make assumptions about then be swept back up into the mixed-phase the size, density, and shape of the particles, as well as region, and grow again by accretion. If this process the amount of emission coming from only the clouds, occurs a number of times, the graupel grows to these sensors provide a very indirect measure of pre­ become what we call hail. cipitation. Also, passive sensors can infer only the total ● As the snow crystals in cumulonimbus clouds fall accumulated depth of precipitation in the cloud, not and get close to the 0°C region, they stick together its vertical structure. The unique aspect of the TRMM and become large collections, or aggregates, of satellite is that it utilizes passive instruments as well as snow crystals. Subsequently, as they continue to fall, active instruments which can see the full vertical they start to melt so that a ring of liquid water forms structure of precipitation in the cloud, thus providing around the aggregate. Because liquid water reflects more accurate rainfall measurement. much more energy back to the radar compared to “There are many other climatically important measure­ ice, and because it only takes a small coating of liq­ ments obtained from satellites, such as the vertical uid water for the aggregate to look like a raindrop temperature structure of the atmosphere, sea surface to the radar, the radar senses that it is seeing really temperature and wind, total ozone concentration, big drops. This is what produces the radar bright ocean productivity, and land biomass. These data are band (melting aggregates of snow flakes). As the available from NASA and NOAA (National Oceanic & particles continue to fall below the bright band, the Atmospheric Administration). large aggregate eventually melts into a large rain­ “The TRMM orbit limits its measurements to latitudes drop which, because of aerodynamic drag, eventual­ between 35°N and 35°S. TRMM does not acquire obser­ ly breaks up into smaller drops—which reduces the vations at higher latitudes. There are no other direct amount of power returned to the radar. The bright measurements of rainfall from satellites as accurate as band layer shows up clearly on TRMM radar images. TRMM. There are several military satellites with passive ● An advantage of TRMM over other satellites is its sensors that observe every place on Earth two times ability to use radar to penetrate through clouds, each day, but because they are in Sun synchronous providing scientists with the three-dimensional orbits, they measure rain at the same local time at each structure of the rain formation. This is important place each day, a poor way to observe rain. Since rain­ since it is the distribution of latent heat within fall occurs in highly variable patterns, observations at clouds that affects the large-scale circulations of the each place should be made at various times through­ atmosphere. Recall that latent heat is released when out the day, as is done by TRMM. Also, passive sensors water changes phase: vapor to liquid and liquid to measure only the total integrated rainfall rate, but solid. Depending on the strength of the updraft and radars (like those on TRMM) can measure the vertical other properties of the surrounding atmosphere, profile of rain, which is important for understanding different clouds may release latent heat at different where the rain is forming, whether it is reaching the heights in the atmosphere. Forecast models need ground, and its effects on the stability and circulation this information on the distribution of latent heat of the atmosphere.” (inferred from radar structure) to accurately predict How passive sensors (microwave radiometers) and weather. active sensors (radars) work PREREQUISITE KNOWLEDGE A passive sensor (a radiometer) simply receives and measures the energy emitted by its target objects PART 1 (raindrops, in this case); TRMM radiometers are also How satellites observe weather and other sensitive to the energy emitted by the