A Remote Sensing A Remote Sensing SamplerSampler

Typical reflectance Typical reflectance spectraspectra

Remote Sensing Applications Consultants - http://www.rsacl.co.uk

Even within a class of materials there are differences in spectral signatures

Nahum Gat (1998)

Near surface remote sensing in Pinedale, Wyoming - sensor is seeing a combination of vegetation and soils and how that changes through the season

NDVI = NIR – R/NIR + R

(Prihodko, Chong, Steltzer and Shory, unpublished data)

Some sensors acquire two or three

bands within the spectrum, and some

acquire hundreds

LASP/Univeristy of Colorado, Boulder

NASA

Sensors operate at different spectral, spatial and temporal scales

1m – Quickbirdhttp://www.spaceimaging.com

10m ~SPOT 30m ~TM

250m ~MODIS

500m ~MODIS

1Km ~AVHRR

Four Mile Fire, Boulder County, Colorado – September 2010High-resolution (sub-meter) DigitalGlobe images

1990 2000

Greeley, Colorado

GeoCover (GLCF 2005)

Landsat TM

June 23, 1990

Landsat MSS

August 15, 1973

Landsat ETM+

September 20, 2002

Landsat ETM+

June 27, 2006

MODIS images with statewide greenness standardized across years, showing declines due to killed trees, which appear red in the high resolution image.

Percent Ground CoverVegetation Continuous Field (MODIS MOD44B) – 250m

Hansen, M., R. DeFries, J.R. Townshend, M. Carroll, C. Dimiceli, and R. Sohlberg (2006), Vegetation Continuous Fields MOD44B, 2001 Percent Tree Cover, Collection 4, University of Maryland, College Park,

Maryland, 2001.

Normalized Difference Vegetation Indices

NDVI – AVHRR

R. Boone, using AVHRR Pathfinder NDVI

Sea Surface Temperature, May 2001 - MODIS

NASA Science Earth

City Lights (DMSP City Lights (DMSP program)program)

Nighttime Lights of the World: 1994-95 Christopher D. Elvidge http://sedac.ciesin.org/gpw-v2/presentations/ChrisElvidge/nightCD/world95.html

Nighttime Lights data also shows regions of high fire activity

White – human settlement Green – gas flaresRed – ephemeral lights (fires) Blue – fishing boats

Nighttime Lights of the World: 1994-95 Christopher D. Elvidge http://sedac.ciesin.org/gpw-v2/presentations/ChrisElvidge/nightCD/world95.html

MODIS Burned Area Product (500m)Blue – July

Green – JanuaryRed - June

http://modis-fire.umd.edu/index.html

MODIS Active Fire Product – Four Mile Canyon Fire

The MODIS instrument on NASA’s Aqua satellite captured this natural-color image of the fire at 2:40 p.m. local time on September 7, 2010. The red outline corresponds with the unusually high surface temperatures associated with an active fire. Credit: NASA/MODIS: http://www.nasa.gov/topics/earth/features/fourmile-canyon-fire.htmlhttp://modis-fire.umd.edu/Active_Fire_Products.html

EOS (Earth Observing System) AQUA satellite –AIRS (Atmospheric Infrared Sounder)

http://airs.jpl.nasa.govVariations in the height of a surface representing a constant

value of water vapor during the summer and fall of 2005. This water vapor surface is highest in the tropics where vapor amounts are largest.

Shuttle Radar Topography Missionof 2000

More than 80% of the earth’s elevations measures

30 m resolution in US

90 m resolution elsewhere

Galapágos Islands

(Boone 2010)

http://modis-snow-ice.gsfc.nasa.gov/010707co.htmlhttp://modis-snow-ice.gsfc.nasa.gov/

MODIS Snow Cover – Colorado January 2007image courtesy of NASA's Earth Observatory.