WEEKLY OCEAN NEWS

WEEK SIX: 11-15 October 2010

ITEM OF INTEREST --

• Celebrate Earth Science Week -- The National Oceanic and Atmospheric Administration, including the National Weather Service, along with NASA, the US Geological Survey and several professional scientific organizations such as the American Geological Institute have recognized this week (10-16 October 2010) as Earth Science Week to help the public gain a better understanding and appreciation for the earth sciences and to encourage stewardship of the Earth. This year's theme for the 12th annual Earth Science Week is "Exploring Energy", designed to "engage young people and the public in learning about Earth's energy resources." [American Geological Institute]

Ocean in the News

• Eye on the tropics --
The last week was relatively inactive across the tropical waters of the Northern Hemisphere's ocean basins:
• In North Atlantic basin, a subtropical low-pressure system formed over the waters of the southwestern Atlantic north of Puerto Rico early last week. As a subtropical low, this system had characteristics that were both tropical and extra-tropical. However, by midway through the week, this system evolved into a tropical system, becoming Tropical Storm Otto as it traveled to the north and then to the northeast. By the end of the week, Otto had strengthened to become the eighth hurricane of the 2010 Atlantic hurricane season. Over the weekend, Hurricane Otto continued traveling to the northeast as a category 1 hurricane on the Saffir-Simpson Hurricane Scale. By the end of the weekend, Hurricane Otto had weakened to a tropical storm over the North Atlantic. The NASA Hurricane Page has additional information and satellite imagery on Otto, which had originally been designated as Subtropical Storm 17.
• In western North Pacific, Tropical Depression 14W formed over the South China Sea near China's Hainan Island early in the week. However, this tropical depression was short-lived as it weakened over southern China. See the NASA Hurricane Page for additional information, along with satellite images of TD 14W.
• A shift in the GRIP mission emphasis --
While the portion of NASA's six-week Genesis and Rapid Intensification Processes (GRIP) experiment that involved data-collection on using aircraft and an autonomous drone ended one week ago, the data analysis phase is now underway for this highly successful field experiment designed to study how hurricanes can rapidly form from tropical disturbances. During the experiment, 15 science flights were conducted by NASA's DC-8 research aircraft and the Global Hawk, the autonomous drone. Flights above Hurricane Karl were highly successful, helping fulfill the mission's stated objectives. [NASA GSFC]
• Nautical charts for Arctic coastal states improved through collaboration --
At a recent meeting in Ottawa, a new Arctic Regional Hydrographic Commission was established in which the United States, led by NOAA's Office of Coast Survey, has joined with the other Arctic Coastal States of Canada, Denmark, Norway and Russia in a collaborative effort to develop nautical charts that will improve the safety of mariners transiting the Arctic. [NOAA News]
• Proposal made to place five Atlantic sturgeon populations on the endangered/threatened list --
Last week, NOAA’s Fisheries Service proposed that five populations of Atlantic sturgeon along the US East Coast should receive protection under the federal Endangered Species Act. The salmon population in the Gulf of Maine was proposed to be listed as threatened, while those Chesapeake Bay, New York Bight, Carolina, and South Atlantic populations were to be considered for the endangered status list. [NOAA News]
• Gulf oil spill remains in the news --
Several newsworthy items occurred during the last week concerning the leaking oil well that created last spring's infamous BP/Deepwater Horizon explosion and subsequent oil spill:
• NOAA officials reopened nearly 3000 square miles of Gulf of Mexico waters off eastern Louisiana today to commercial and recreational fishing after consultation with the US Food and Drug Administration and officials with the Gulf Coast States. As of this time, nearly 90 percent of federal waters of the Gulf are open after the oil spill from the Deepwater Horizon BP disaster. [NOAA News]
• NOAA's Administrator, Dr. Jane Lubchenco and the Office of Management and Budget (OMB) Acting Director, Jeffrey Zients, released a statement concerning the report that NOAA produced and OMB reviewed on the movement of oil from the Deepwater Horizon BP spill. [NOAA News]
• A transcript was made available of the keynote address delivered by the NOAA Administrator, Dr. Jane Lubchenco, to the American Bar Association’s Section of Environment, Energy, and Resources (SEER) Law Summit in New Orleans the week before last. Her remarks were on NOAA science and the Gulf Oil spill. [NOAA News]
• Construction contract awarded for NOAA's Atlantic Marine Operation Center --
During this last week, NOAA officials announced that a contract was awarded to a construction company to repair the agency's Marine Operational Center-Atlantic in the Norfolk, VA port, which houses NOAA’s National Ocean Service Atlantic Hydrographic Branch, Navigational Response Team, Oceanic and Atmospheric Research, and Public Health Services, as well as being the home port for the NOAA Ship Thomas Jefferson. [NOAA News]
• Special Civil War maps and nautical charts collection unveiled ---
NOAA recently announced that in honor of the 150th anniversary of the start of the Civil War in 2011, a historical collection of maps, charts, and documents called "Charting a More Perfect Union" has been placed on a special website. This collection, which includes over 400 documents that were made by the US Coast Survey during the war, is available free to the public. [NOAA News]
• Mapping the global water vapor for August --
NASA scientists recently released an image showing the global distribution of water vapor during August 2010 obtained from data collected by the Atmospheric Infrared Sounder (AIRS) and the Advanced Microwave Sounding Unit (AMSU-A) sensors onboard NASA’s Aqua satellite. [NASA Earth Observatory]
• Arctic sea ice shrinks to 2010 summer minimum --
Researchers at NASA's Goddard Space Flight Center who have been analyzing data on the Arctic sea ice obtained by the AMSR-E instrument onboard NASA's Aqua satellite claim that the sea ice covering the Arctic Ocean reached its annual minimum extent on Wednesday, 29 September 2010. Scientists at the National Snow and Ice Data Center noted that the extent of the sea ice coverage at its minimum was the third lowest extent since satellite surveillance of the sea ice began in 1979, with 2007 and 2008 summers having smaller areal extents of ice. [NASA's Earth Science News Team]
• Investigating the oxygenation of Earth --
An international team of scientists from Arizona State University, Harvard University and research institutions in Denmark, Sweden and the United Kingdom have developed techniques for studying the process of oxygenation, where the levels of free oxygen in the early Earth's oceans and atmosphere rose quickly during the Phanerozoic era approximately 550 million years ago. These researchers claim that plants played a dominant role in the process. [Arizona State University News]
• New deep-sea hot springs are discovered --
Scientists from Germany's MARUM Center for Marine Environmental Sciences and the Max Planck Institute for Marine Microbiology who were on the German research vessel Meteor recently discovered a new deep-sea hydrothermal vent approximately 1000 meters below the surface waters of the central tropical Atlantic Ocean at a distance of approximately 500 kilometers to the southwest of the Azores. These researchers claim that these hydrothermal vents may contribute more to the thermal budget of the world's oceans than previously assumed. [Max Planck Society]
• An All-Hazards Monitor --
This Web portal provides the user information from NOAA on current environmental events that may pose as hazards such as tropical weather, drought, floods, marine weather, tsunamis, rip currents, Harmful Algal Blooms (HABs) and coral bleaching. [NOAAWatch]
• Global and US Hazards/Climate Extremes --
A review and analysis of the global impacts of various weather-related events, to include drought, floods and storms during the current month. [NCDC]
• Earthweek --
Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Abyssal Storms

Until recently, ocean scientists thought of the deep ocean abyss as a dark and cold, but serene place where small particles rained gently onto the ocean floor. However, instruments lowered to the sea floor to measure ocean motion or currents and resulting mobilization of bottom sediments detected a much more active environment. Scientists found that bottom currents and abyssal storms occasionally scour the ocean bottom, generating moving clouds of suspended sediment. A surface current of 5 knots (250 cm/sec) is considered relatively strong. A bottom current of 1 knot (50 cm/sec) is ripping. Although this may be called an abyssal storm, the water motion pales by comparison to wind speeds in atmospheric storms.

Abyssal currents and storms apparently derive their energy from surface ocean currents. Wind-driven surface ocean currents flow about the margins of the ocean basins as gyres centered near 30 degrees latitude. (Refer to Figure 6.6, page 152, in your textbook.) Viewed from above, these subtropical gyres rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. For reasons given in Chapter 6 of your textbook and this week's Supplemental Information, surface currents flow faster, are narrower, and extend to greater depths on the western arm of the gyres. These are known as western boundary currents and include, for example, the Gulf Stream of the North Atlantic basin. Abyssal currents are also most vigorous on the western side of the ocean basins, moving along the base of the continental rise, which is on the order of several kilometers deep.

Abyssal storms may be linked to or may actually be eddies (rings) that occasionally break off from the main current of the Gulf Stream (and other western boundary currents). During an abyssal storm, the eddy or ring may actually reach to the bottom of the ocean where the velocity of a bottom current increases ten-fold to about 1.5 km (1 mi) per hr. While that is an unimpressive wind speed, water is much denser than air so that its erosive and sediment-transport capacity is significant even at 1.5 km per hr. At this higher speed, the suspended sediment load in the bottom current increases by a factor of ten. Abyssal storms scour the sea floor leaving behind long furrows in the sediment. After a few days to a few weeks, the current weakens or the eddy (ring) is reabsorbed into the main surface circulation and the suspended load settles to the ocean floor. In this way, abyssal storms can transport tons of sediment long distances, disrupting the orderly sequence of layers of deep-sea sediments. Scientists must take this disruption into account when interpreting the environmental significance of deep-sea sediment cores.

Concept of the Week: Questions

1. In the subtropical ocean gyres, boundary currents flow faster on the [(western)(eastern)] side of an ocean basin.
2. Currents in an abyssal storm erode, transport, and redeposit sediments that have accumulated on the [(continental shelf)(deep ocean bottom)].

Historical Events

• 11 October 1737...A deadly cyclone and storm surge of 42 ft raced up the Hooghly River in India and through the city of Calcutta destroying an estimated 40,000 boats and drowning as many as 300,000 people. (The Weather Doctor)
• 11 October 1846...A very intense hurricane caused great destruction in the Florida Keys. Key West was virtually destroyed with 5 feet of water reported in the city. Fort Taylor was reduced to ruins. (Intellicast)
• 11 October 1897...Property saved at Cape Hatteras, NC. During a severe storm, the surf threatened to wash away a fish house, with valuable nets and other gear. Surfmen saved the property and took it to a place of safety. They also assisted a lighthouse keeper by removing lenses from the beacon to a secure place. The lighthouse was in danger of being washed away by the sea. (US Coast Guard Historian's Office)
• 12 October 1492...Italian explorer Christopher Columbus sighted and landed on an island (possibly Watling Island) in the Bahamas during his travels westward across the Atlantic Ocean in search of an ocean route to eastern Asia. Apparently he underestimated the size of the world and assumed that he had reached East Asia after setting sail with three ships from Palos, Spain on 3 August 1492. During this expedition, which was the first known European expedition to the Americas since the 10^th century Viking colonies in Newfoundland, he sighted Cuba and landed on Hispaniola. (The History Channel)
• 12 October 1886...A hurricane made landfall between Sabine Pass, TX and Johnson's Bayou, LA. Waves were said to be as high as 2-story buildings. The surge extended 20 mi inland, with 150 people killed. Survivors clung to trees or floated on mattresses. Only two of 100 homes in Sabine Pass were reparable. (Accord Weather Calendar)
• 12 October 1954...Hurricane Hazel pounded Haiti and the island of Hispaniola with winds of 125 mph. Many villages were reported totally destroyed and more than 1000 Haitians died. (The Weather Doctor)
• 12 October 1965...End of Project Sealab II where teams of naval divers and scientists spent 15 days in Sealab moored 205 feet below surface near La Jolla, CA. (Navy Historical Center)
• 12 October 1979...The lowest observed sea-level barometric pressure (870 millibars or 25.69 inches of mercury) was recorded near Guam in the western Pacific Ocean at the center of Typhoon Tip. (The Weather Doctor)
• 13 October 1775...Birthday of U.S. Navy. The Continental Congress established the Continental Navy, later the U.S. Navy. (Naval Historical Center)
• 13 October 1884...The longitude that passes through the principal Transit Instrument at the Observatory in Greenwich, England was selected as the single universal meridian at the International Meridian Conference held in Washington, DC. A universal day was also selected. (Today in Science History)

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Prepared by AMS DS Ocean Central Staff and Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2010, The American Meteorological Society.