Section 2.3 Remote Sensing Earth Science Section 2.3 Remote Sensing

Objectives Compare and contrast different types of remote sensing. Discuss how satellites and sonar are used to map Earth’s surface and its oceans. Describe the Global Positioning System and how it works.

Vocabulary satellite remote sensing Landsat satellite TOPEX/Poseidon satellite sonar Global Positioning System Geographic Information System

Remote Sensing The process of gathering data about Earth using instruments mounted on satellites, airplanes, or ships is called remote sensing.

Landsat Image of Lake Michigan Landsat Satellites Landsat Image of Lake Michigan Landsat 7 Satellite

Landsat Satellite Landsat satellites record reflected wavelengths of visible light and infrared radiation from Earth’s surface, and then computers convert the information into digital images.

Uses for the Landsat Satellite Landsat data are also used to study the movements of Earth’s plates, rivers, earthquakes, and pollution. The Bahamas from a Landsat Satellite

TOPEX/Poseidon Satellite The TOPEX/Poseidon satellite uses radar to map features on the ocean floor.

TOPEX/Poseidon Satellite The satellite transmits high-frequency signals to the surface of the ocean. The receiving device picks up the reflected echo. The distance is calculated using the known speed of light and the time it takes for the signal to be reflected.

Uses for the TOPEX/Poseidon Satellite Scientists also use TOPEX/Poseidon to estimate global sea levels and study tidal changes and global ocean currents. This is a TOPEX/Poseidon Image Mapping Wave Heights This is a TOPEX/Poseidon Image of El Nino

Sea Beam Sonar is the use of sound waves to detect and measure objects underwater.

Sea Beam Sea Beam technology uses sonar to map the ocean floor from a ship.

Sea Beam A sound wave is sent from a ship toward the ocean floor. A receiving device picks up the returning echo when it bounces off the seafloor.

Sea Beam A computer calculates the distance from the ship to the ocean floor using the speed of sound in water and the time it takes for the sound to be reflected. This is a type of Sea Beam called a Sidescan Sonar. A system like this was used to search for the Challenger Space Shuttle

A Sea Beam Image of the Mid Atlantic Ridge Uses for the Sea Beam Sea Beam technology is used by fishing fleets, deep-sea drilling operations, oceanographers, volcanologists, and archaeologists. A Sea Beam Image of the Mid Atlantic Ridge

Global Positioning System The Global Positioning System (GPS) is a satellite navigation system that allows users to locate their approximate position on Earth. GPS Satellite

Global Positioning System These satellites can also relay information to a GPS receiver about elevation, direction of movement, and speed. GPS Satellites Orbiting the Earth

Uses for GPS Technology GPS technology is used extensively in navigation by airplanes and ships.

Uses for GPS Technology GPS receivers detect signals from the 27 GPS satellites orbiting Earth. Using signals from at least three satellites, the receiver can calculate location within 10 m. GPS receivers also help people in everyday life to find a destination or determine their current location.

Geographic Information System The Geographic Information System (GIS) uses a worldwide database to create layers, or “themes,” of information that can be placed one on top of the other to create a comprehensive map. GIS System – Bases in Dallas and Tokyo

Geographic Information System The Geographic Information System (GIS) uses a worldwide database to create layers, or “themes,” of information that can be placed one on top of the other to create a comprehensive map. Examples of GIS Layers

Geographic Information System This is a GIS Map of Ogden, Utah Showing the Route of a Marathon This is an Example of GIS Layers