Measuring Water Depth from the International Space Station: Image o...

	Measuring Water Depth from the International Space Station: Image o...
	by NASA -- Astronaut photographs eol.jsc.nasa.gov/scripts/sseop/photo...
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	Looking out the window of the International Space
	Station, astronauts often take the time to admire and
	photograph tropical islands and coral reefs. From an
	altitude of 400 km and with only a digital camera as a
	tool, it seems impossible to make detailed measurements
	of the depth of underwater features. However, a new
	technique developed by NOAA scientists has done just that-
	-plotted the depths of lagoon features at Pearl and
	Hermes Reef, northwest Hawaii, using digital astronaut
	photography from the International Space Station (ISS).
	Measuring water depth is an important step in mapping
	coral reef environments. Even though digital cameras are
	designed to visually approximate film photographs, the
	information they collect is similar to the bands of
	different wavelengths of light collected by multispectral
	instruments on satellites. NOAA scientists developed an
	algorithm that could estimate bathymetry from the blue
	and green bands in IKONOS satellite data. After
	calibrating the astronaut photography to the signal in
	the IKONOS data, the same algorithm could be successfully
	used with the blue and green channels in the astronaut
	photography. An accuracy assessment of the
	eol.jsc.nasa.gov/newsletter/CoastalZone/default.htm
	bathymetry map shows good correspondence between
	reference data, IKONOS, and ISS data. Analysis of the
	Pearl and Hermes imagery was completed by Rick Stumpf and
	Kris Holderied at the NOAA National Ocean Service. NOAA
	NOS's most recent coral reef mapping activities have
	focused on producing ccma.nos.noaa.gov/rsd/products.html
	benthic habitat maps of the Northwest Hawaiian Islands
	for the Office of National Marine Sanctuaries. NOAA has
	primary responsibility for mapping activities in U.S.-
	Flag waters under the U.S. Coral Reef Task Force's
	coralreef.gov/mapping/mpwg.cfm Mapping Implementation
	Plan . Partnership with Julie Robinson, Earth
	Observations Laboratory (Lockheed Martin), Johnson Space
	Center, has been facilitated by NASA support for
	eol.jsc.nasa.gov/Reefs/ Coral Reef Remote Sensing
	projects and collaborations.

	References:

	Stumpf, R. P., K. Holderied, J. A. Robinson, G. Feldman,
	N. Kuring. Mapping water depths in clear water from
	space. Coastal Zone 03, Baltimore, Maryland, 13-17 July
	2003.
	http://eol.jsc.nasa.gov/newsletter/CoastalZone/defau
	lt.htm Stumpf, R.P. K. Holderied, and M. Sinclair. 2003b.
	Determination of water depth with high-resolution
	satellite imagery over variable bottom types. Limnology
	and Oceanography 48(1, part 2):547-556.

	Date Published: 2011-07-01 02:12:58
	Identifier: ISS005-E-13927
	Item Size: 222742
	Media Type: image

	# Topics
	What -- International Space Station (...
	What -- Hermes
	What -- NOSS
	What -- Earth
	Where -- Hawaii
	Where -- Johnson Space Center (JSC)
	Where -- Maryland

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