Gathering Global Data: Mind Bending GPS Occultations
The GPS system is used for more than finding your way around a new city. By analyzing the signals sent and received by GPS satellites we can continuously examine the Earth's dynamic atmosphere for a wide range of purposes, including weather forecasting and climate change monitoring.Copyright (left) NIST and (right) Mike Meares, US Air Force, Wikipedia http://www.nist.gov/pml/div688/grp40/gpsarchive.cfm http://en.wikipedia.org/wiki/File:2_SOPS_space_systems_operator_040205-F-0000C-001.jpg
Students learn about the remote sensing radio occultation technique and how engineers use it with GPS satellites to monitor and study the Earth's atmospheric activity. Students may be familiar with some everyday uses of GPS, but not as familiar with how GPS technology contributes to our ongoing need for great amounts of ever-changing global atmospheric data for accurate weather forecasting, storm tracking and climate change monitoring. GPS occultations are when GPS signals sent from one satellite to another are altered (delayed, refracted) by the atmosphere passed though, such that they can be analyzed to remotely learn about the planet's atmospheric conditions.
Engineers and scientists use GPS satellites and low-Earth orbit (LEO) satellites to study the atmosphere of Earth, which provides information that is helpful in the analysis of weather, climate, pollution, ozone and solar radiation. Although GPS satellites designed by engineers are most commonly used for navigation, a technique called GPS occultations is now extensively used gather atmospheric data from all over the planet. Using satellite information gathered via this technique enables us to learn more about our weather and climate and how the atmospheric layers function and interact with one another.
After this lesson, students should be able to:
- Describe how disturbed GPS signals are analyzed in order to understand the type of weather they passed through.
- Compare actual results to expected results to find out reasons for any differences.
- Describe how GPS satellites are used for more than just navigation, specifically for natural disasters and other atmospheric phenomena.