Live from the ocean floor: new oil leak widget features 'Spillcam'

The following widget is provided by PBS.org to calculate the extent of the oil spill resulting in the Gulf of Mexico due to the explosion and subsequent sinking of the Deep Horizon oil drilling rig.
The flow rate can be adjusted to take into account the various figures being bounced around by various groups.

BP's estimate that only 5,000 barrels of oil are leaking daily from a well in the Gulf of Mexico, which the Obama administration hasn't disputed, could save the company millions of dollars in damages when the financial impact of the spill is resolved in court, legal experts say.
But BP could be facing a crippling liability of up to $10bn unless its latest effort to contain the oil leak in the Gulf of Mexico meets with success. (CNBC)
A preliminary internal investigation by BP has found that there were “several new warning signs of problems” in the hours before the Deepwater Horizon explosion, according to US lawmakers who were briefed by the company on Tuesday. (CNN)

Regardless of which figures are used, this is clearly an unprecedented disaster.
see : underwater video of oil slick (OceanFuturesSociety)
Experts at NOAA announce that they have extended the area where fishing is currently forbidden in the Gulf of Mexico. The closed area now represents 54,096 square miles, which is slightly more than 22 percent of Gulf of Mexico federal waters.

However, that didn’t stop BP Chief Executive Tony Hayward from claiming that the ongoing and largely uncontained spill is “relatively tiny” when compared to the volume of the Gulf of Mexico. (Daily Telegraph)
BP attempts to plug Gulf of Mexico oil leak with mud in 'top kill' technique : company awaits test results before trying to choke off Deepwater Horizon leak by force-feeding it mud and cement. (The Guardian)

By the way, more than 650,000 gallons of chemical dispersant have gone into the Gulf of Mexico to try to break up the oil.
But after giving BP the go-ahead to use the chemical, and to inject it undersea, the Environmental Protection Agency changed course yesterday and demanded that BP switch to a less toxic dispersant. (The Guardian)

Meanwhile, as BP’s solutions to stopping the leak and cleaning up the spill continue to struggle, a new savior has stepped up: Kevin Costner who is in real life, an avid environmentalist, fisherman, and greentech entrepreneur.
While making Waterworld in 1995, Costner was troubled by oil spills like the Exxon Valdez and started developing a system to cruise the surface of the sea and clean oily water.
“The machines are essentially like big vacuum cleaners, which sit on barges and suck up oily water and spin it around at high speed,” his business partner said in the Los Angeles Times. “On one side, it spits out pure oil, which can be recovered. The other side spits out 99% pure water”.
BP and the U.S. Coast Guard plan to test six of the massive devices this week.

Volume and depth of the world's oceans calculated

Fly down into the Marianas Trench
(Courtesy of NOAA's Marine Geology and Geophysics Division)

From ScienceDaily

How high is the sky? Scientists have a pretty good handle on that one, what with their knowledge of the troposphere, stratosphere an the other "o-spheres." Now, thanks to new work headed by the Woods Hole Oceanographic Institution (WHOI), they are closing in on the other half of that age-old query: How deep is the ocean?

They're also tackling an even more intriguing -- if less romantic -- question: What is the volume of the Earth's oceans? It's hard to imagine Irving Berlin putting those words into the mouth of a serenading lover -- as he did in his classic song, "How Deep is the Ocean?" -- let alone the answer: 1.332 billion cubic kilometers.

But that figure is pure music to the ears of Matthew Charette, an associate scientist in WHOI's Department of Marine Chemistry and Geochemistry who is part of a research effort to audit all the water on the planet. "A lot of water values are taken for granted," he says. "If you want to know the water volume on the planet, you Google it and you get five different numbers, most of them 30- or 40-year-old values."

Until now.

Using satellite measurements, Charette and co-investigator Walter H.F. Smith, a geophysicist at the National Environmental Satellite, Data and Information Service of the National Oceanic and Atmospheric Administration, have come with up the new ocean volume figure. Their work, funded in part by the EarthWater Institute, is published in the current issue of the journal Oceanography.

The researchers report that the world's total ocean volume is less than the most recent estimates by a volume equivalent to about five times the Gulf of Mexico, or 500 times the Great Lakes. While that might seem a lot at first glance, it is only about 0.3% lower than the estimates of 30 years ago.

What may be more interesting, he says, is how accurate scientists were in the past, using cruder techniques to measure ocean depth. As long ago as 1888, for example, John Murray dangled lead weights from a rope off a ship to calculate an ocean volume -- the product of ocean area and mean ocean depth -- just 1.2% greater than the figure Charette and Smith now report.

Starting in the 1920s, researchers using echosounders improved depth estimates significantly, according to the researchers. Most recently, Smith and others have pioneered the use of satellites to calculate ocean volume.

The trend toward a progressive lowering of volume estimates is not because the world's oceans are losing water. Rather, it reflects a greater ability to locate undersea mountain ranges and other formations, which take up space that would otherwise be occupied by water.

Satellite measurements reveal that ocean bottoms "are bumpier and more mountainous than had been imagined," said Smith. As measurements improve, ocean-volume values are lowering, he notes, emphasizing that this does not reflect an actual lessening of water but a more accurate accounting of undersea formations.

Satellite-based radar cannot "see" the ocean bottom, he explains. Rather, it measures the ocean surface, which reflects what lies beneath. For instance, if a mountain range lurks under a certain part of the ocean, the surface above it will bulge outward. "I take the data set and estimate the location and height of the mountains," Smith says.

The satellite project has covered virtually all the world's oceans, except for some areas of the Arctic that are covered with ice, he says. The result is a "new world map" of the oceans, Smith adds. "Matt and I are seeing a better picture of the shape and volume of oceans."

But satellite measurements have their shortcomings. "There is a problem of spatial resolution, like an out-of-focus camera," says Smith. "We're measuring the sea surface that is affected by mountains," he says, "but we're seeing only really big mountains, and in a blurry way. The resolution is 15 times worse than our maps of Mars and the moon."

Consequently, the researchers say, more ship-based measurements are needed to augment and "fine tune" the satellite data. And so far, ship-based sonar and other instrumentation have mapped only 10% of the Earth's seafloor. "We have gaps in echosounding measurements as wide as New Jersey," says Smith.

It would take a single ship 200 years (or 10 ships 20 years) to measure all the ocean-floor depths with an echsounder, according to published U.S. Navy estimates. "That would come to about $2 billion," Smith says. "NASA is spending more than that on a probe to [the Jupiter moon] Europa."

Charette and Smith are not sure why so little ship-based ocean mapping has been done throughout history. It may be because ocean depth and volume seem to have few direct, practical implications.

However, Charette notes, accurate estimates of ocean depth and volume could tie in with the growing field of ocean observation and exploration as well as, perhaps, climate change models and estimates of salt in the oceans.

And for those of you wondering -- as Berlin put it so eloquently in his music -- if you ever lost your love, how much would you cry? Apparently not as much as you might have 30 years ago. The study's calculation of the ocean's mean depth is 3,682.2 meters -- that's 21-to-51 meters less than previous estimates.

Links :

• LiveScience
  
• Ocean Planet
• Mariana Trench, deepest part of the world's oceans (11033 meters -36,201 feet)
  
• The deepest place on Earth : Part 1 / 2 / 3 / 4 / 5
  

NOAA meets on benefits of improved 3D positioning

Nautical charts have all a horizontal datum.
On a global basis, the International Hydrographic Organization (IHO) designated the use of the World Geodetic System (WGS) as the universal datum.
Since then, the horizontal features have been based on WGS 84 or in other geodetic reference systems which are compatible, such as NAD 83 (in the US) or the ITRF combined with the GRS80 ellipsoid.

But what about heights ?

Nautical charts have depths referred to different tidal surfaces, which may vary from chart to chart. Tide heights are given relative to the "datum" which in most cases is one of different benchmarks corresponding to low tides of varying extremeness.
In the United States, Mean Lower Low Water (MLLW) is the typical low water reference surface (MLWS in Nederlands, LAT in Germany...)
By the way, to support harbor and river navigation, bridge clearances are also typically referenced to mean high water (MHW): not to a low water...

Vertical datum used by software covering the whole planet (such as Google Earth) is the WGS84 EGM96 Geoid which gives altitudes in meters above sea level (MSL) while seafloor mapping software (Hypack, Olex...) reference bathymetric survey data to Low Water vertical datums...

In a goal of uniformity, seamless VDatum software emerges to cover all of the U.S. coastal areas out to 25 nautical miles from land. The availability of VDatum nationwide will enable bathymetric, topographic and coastline data to be easily transformed and assembled in a manner that complements dissemination through national databases.

Last week the National Oceanic and Atmospheric Administration held a Federal Geospatial Summit in Maryland to discuss the proposed improvements to the National Spatial Reference System (NSRS) in the US.
The meeting discussed how the replacement of the North American Datum of 1983 (NAD83) and the North American Vertical Datum of 1988 (NAVD88) will positively impact measurement and operations.

The agency recently received the findings of an independent study that shows the benefits to the U.S. economy for better positioning.
The study found that the NSRS provides a benefit of more than $2.4 billion annually to the U.S. economy, and that an additional $522 million in economic benefits could be realized by improving the precision of elevation measurements, with an estimated $240 million saved by improved floodplain management.

The existing vertical datum means elevation errors from 16 inches to 6 feet at sea level.
The improved Gravity for the Redefinition of the American Vertical Datum (GRAV-D) reference system would improve that error to under an inch.

Links :

• overview of the 'U.S. economy for better positioning' study / full report
• NSRS / Elements of NSRS
  
• NOAA : Tutorial geodesy
• Height modernization program
  
• Water level information

Image of the week : plankton arrives in Scandinavia

Envisat's MERIS acquired this image on 3 May 2010 at a resolution of 300 m.

Envisat captures a crescent-shaped string of plankton in the North Sea weaving through the Scandinavian region. Norway (left) and Sweden (right), part of the Scandinavian Peninsula, are visible at the top, and Denmark is at bottom right.

The emerald green lake seen in Sweden is Vänern, the largest in the country..
The green water around Denmark is due to sediments being transported in the water.
Also visible (image centre) is Norway’s second largest fjord, Hardangerfjord at the north of Bergen.

The plankton, which forms the most abundant life in the oceans, is mainly composed of microscopic marine plants that drift on the surface of the sea or near it.
The plankton was nicknamed "the grass of the sea" because it is the staple food for a lot of other forms of marine life.
As the plankton contains pigments of chlorophyll for photosynthesis, these simple organisms play a role similar to terrestrial green plants in the process of photosynthesis.

Plankton is capable of transforming inorganic compounds such as water, nitrogen and carbon in complex organic materials. Because of his ability to digest these compounds, it is estimated that the plankton contributes as much as terrestrial vegetation to extract carbon dioxide from the atmosphere.

The chlorophyll used for photosynthesis by these microscopic organisms gives color to the waters of the ocean where they concentrate, which provides a means of detecting from space through sensors dedicated to the study of "ocean color" as the camera MERIS (Medium Resolution Imaging Spectrometer) Envisat.

Links :

• Envisat’s MERIS captures phytoplankton bloom (2002)
• Earth from Space: 'The grass of the sea' (2006)
• NASA : Phytoplankton bloom in the North Atlantic
  
• NASA : Phytoplankton Bloom in the Arabian Sea
  

Marine GeoGarage sightseeing contest : win a 'Chart Premium' subscription

Following to our previous post :

As Marine GeoGarage gives to the user the possibility to superimpose official raster charts from International Hydrographic Services upon Google aerial and satellite imagery, it could be interesting to report sights with major differences.

see : NOAA shoreline website

Aerial and satellite Google images are regularly updated with accuracy improvements (see the Historical imagery tool in Google Earth), so the use of the Marine GeoGarage nautical chart opacity tool could become a basic technique for coastal change monitoring.

User feedback :

Users who note a major difference between imagery and nautical chart can report us (contact@geogarage.com) the place using the network link at the bottom left side of the viewer.
http://marine.geogarage.com/routes?anonmap=...........

GeoGarage contest :

We will publish a specific page signaling the different reports (with reference to the user or in an anonymous way).
Every month, the GeoGarage team will select the most significant report and will credit a month 'Premium Chart' for the winner.