Remote sensing of natural hazards Remote sensing = satellite imagery and aerial photography They range from low resolution (weather satellites) to very high res .. capable of detecting objects <1 metre. Hurricane Katrina. 1. Introduction-Instruments: Most satellite images are not photos.
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Remote sensing of natural hazards
Remote sensing =
satellite imagery and aerial photography
They range from low resolution (weather satellites) to very high res ..
capable of detecting objects <1 metre
1. Introduction-Instruments:Most satellite images are not photos
Millennium Island photographed by a crew member on the International Space Station
This image was acquired with a Nikon D3 digital camera fitted with an 800 mm lens
Geostationary: 36,000 km above equator, stay vertically above the same spot, rotates with earth - weather images, e.g. GOES (Geostat. Operational Env. Satellite)
Scanning enables the data to be transmitted back to earth from the satellite. orbits
Sun-synchronous satellites:700-900 km altitude, rotates at circa 81-82 degree angle to equator: captures imagery approx the same time each day (10am +/- 30 minutes) -
Landsat path: earthnow
Intro– Resolution (pixel size) ~1 m to 10km
Low resolution 1km - 10km (international)
Medium resolution 100m -1km (national)
High resolution 10 -100 m (regional)
Very High resolution 1 - 10 metres (local)
Introduction Energy wavelengths used for remote sensing
2. Sensors: Low resolution - weather satellites
Sensors: MODIS – medium resolution
Sensors: ASTER - High resolution
Very high resolution –
e.g Ikonos, Quickbird, GeoEye
GeoEye 50cm resolution: Vancouver Olympic village (April 26, 2009)
Selected satellite remote sensing systems
Tornado Rips Through Maryland, 2002 (west <- east)
Lava flow, New Aiyansh
USGS Volcano Hazards http://volcanoes.usgs.gov/
Earth Observatory: Anak Krakatau
Ikonos satellite on June 11, 2005.
Use of LiDAR digital elevation models for flood plain mapping and mitigation
Remote Sensing for Hazard Assessment: Landslides - Hong Kong
LANDSAT Thematic Mapper colour composite, bands 2, 4 and 6 with band 6 (thermal band) displayed as red and band 4 (visible infra-red) as green.
Red areas represent hot spots and correspond to areas of grassland which have been burnt during the dry season.
4. Remote sensing of hazards by type … Volcanoes
This ASTER image of Mount St. Helens was captured one week after the March 8 ash and steam eruption (2005) http://www.nasa.gov/centers/goddard/earthandsun/mshelenslidar_prt.htm
Avalanches, Bowron Lakes
Climate change: melting polar ice cap
- lake dam collapse:
A chunk of glacier was threatening to fall into an Andean lake and cause major flooding in a Peruvian city of 60,000. If the piece breaks off, ensuing floods would take 15 minutes to reach the city. In 1941, the lake overflowed and caused massive destruction, killing 7,000 people.
Rita: Evolution From Tropical Storm to HurricaneWhile Rita is dragging over both Cuba and the Florida peninsula, she can't draw much power since there is less water available for evaporation. However, once she starts to clear Cuba and Florida, and gets over the warm waters of the Gulf of Mexico, she is able to spin up into a full hurricane. From these images, you can also see that her path will take her across the Gulf, towards the Texas coast.
MODIS Rapid Response System Global Fire Maps
5. Some general websites for remote sensing of hazards
Mapping reference for hazards- Canada
Natural Resources Canada - natural hazards
Dr. George Pararas-Carayannis
Satellite images and digital terrain models for 3D visualisation