Weekly Ocean News

WEEKLY OCEAN NEWS

WEEK SIX: 6-10 October 2008

Ocean in the News

Celebrate Earth Science Week -- The National Oceanic and Atmospheric Administration, to include the National Weather Service, along with NASA, the US Geological Survey and several professional scientific organizations such as the American Geological Institute have recognized next week (12-18 October 2008) 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 10th annual Earth Science Week is "No Child Left Inside", designed to encourage young people to learn about the geosciences, by going outdoors, leaving behind the indoor activities involving the television or computer. [American Geological Institute]
Eye on the tropics -- Several tropical cyclones formed last week over the Atlantic and Pacific:
- In the North Atlantic basin, Subtropical Storm Laura formed at the start of last week over the central North Atlantic as a hybrid storm, but gained tropical characteristics. This system traveled northward and while passing east of Newfoundland by late in the week, lost its tropical characteristics. The NASA Hurricane Center has a description along with satellite images of Tropical Storm Laura.
- In eastern North Pacific, a tropical depression became a tropical storm and eventually Hurricane Marie off the coast of Mexico last week. This category 1 hurricane (on the Saffir-Simpson Scale) was the sixth hurricane of the 2008 hurricane season in the eastern North Pacific basin. As of Sunday, the hurricane had weakened to a tropical storm that was continuing to the northwest, well off the coast. Several satellite images and a discussion of Marie are on the NASA Hurricane Page.
  Another named tropical cyclone formed this past weekend off the southwestern Mexican coast, to became Tropical Storm Norbert. As of Sunday, this tropical storm was traveling to the west.
- In western North Pacific, Supertyphoon Jangmi (category 4 on the Saffir-Simpson Scale) crossed the north end of Taiwan one week ago, then weakened as it curved to the north to pass just off the coast of mainland China before curving toward the northeast to dissipate just south of the southern Japanese islands. Satellite images of Jangmi and additional information on this system can be found on the NASA Hurricane Page.
  Tropical Storm Mekkhala organized over the South China Sea one week ago and traveled to the west-northwest before making landfall in northern Viet Nam by midweek.
  Tropical Storm Higos formed just east of the Philippines early last week, traveled across this island nation and continued to the west-northwest across the South China Sea. By Sunday, this storm had weakened to a tropical depression as it was about to make landfall along the southern China coast near Hong Kong. The NASA Hurricane Page has additional information and satellite images for Tropical Storm Higos.
Series of open houses scheduled on potential marine conservation areas --The federal government recently released a schedule for a series of open houses in Washington, DC, Honolulu, HI, Pago Pago, American Samoa and Saipan, Commonwealth of the Northern Mariana Islands within the next month that will be designed to seek public discussion on the recognition and protection of three specific marine areas in the Pacific west of the Hawaiian Islands, in American Samoa and in the western Pacific around the Northern Marianas. [NOAA News]
Applicants sought for advisory councils to national marine sanctuaries -- Several of NOAA's National Marine Sanctuaries are actively seeking applicants to the advisory councils for the individual sanctuaries that represent the public's interest in sanctuary matters and provide advice to the superintendents of these sanctuaries. The openings on the advisory councils are for the Hawaiian Islands Humpback Whale National Marine Sanctuary surrounding the main Hawaiian Islands [NOAA News]; the Gulf of the Farallones National Marine Sanctuary off California's Golden Gate to San Francisco Bay [NOAA News]; the Monterey Bay National Marine Sanctuary off the central California coast [NOAA News] and Gray’s Reef National Marine Sanctuary off the Georgia coast [NOAA News].
Beluga whale population hold steady in Cook Inlet -- NOAA’s Fisheries Service recently reported that an early summer 2008 aerial survey of Alaska's Cook Inlet indicates that the Inlet's beluga whale population appears to have remained steady from the previous year's count; however, the Service's scientists remain concerned that this endangered species has not recovered as earlier hoped. [NOAA News]
Another fisheries survey vessel launched -- The fourth in a series of new fisheries survey vessels, the 208-ft long NOAA Ship Bell M. Shimada, was launched last week at Moss Point, MS and will be assigned a home port along the West Coast; these new vessels are designed to study fish quietly so as not to alter their behavior. [NOAA News]
Shortage of marine scientists foreseen -- A new joint report to Congress by the US Departments of Commerce and Education warns that a serious shortage of research scientists trained to rebuild fish stocks and restore marine species will occur in the next decade. [NOAA News]
Record Arctic ice retreat noted - NASA scientists at the Goddard Space Flight Center report that during a four-week interval in August 2098, the Arctic sea ice melted at a rate faster than previously seen during the nearly 30 years of satellite surveillance; by mid September, the extent of the Arctic sea ice was the second smallest on record. [NASA GSFC] The European Space Agency recently reported that the annual freeze-up of the Arctic Sea ice was underway by the end of September. [ESA]
Air then ocean contributed to thinning of Greenland glacier -- Scientists from New York University, NASA's Wallops Flight Facility, Canada's Memorial University, the Danish Meteorological Institute, and the Greenland Institute of Natural Resources attribute the thinning of the Jakobshavn Isbræ glacier on Greenland to subsurface ocean warming that was preceded by changes in the atmospheric circulation pattern over the North Atlantic. [EurekAlert!]
Ice loss tracked on Greenland -- Researchers from Delft University of Technology in the Netherlands and the University of Texas at Austin have used data from the GRACE (Gravity Recovery and Climate Experiment) satellites to track the contribution of the shrinking Greenland ice cap to the annual rise in global sea level. [Delft University of Technology]
Effects of Ike still apparent -- Recent images obtained from the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) and the MODIS (Moderate Resolution Imaging Spectroradiometer) instruments on NASA’s Terra satellite from over the Upper Texas Gulf Coast help show the magnitude of the devastation from the storm surge and coastal flooding across the region when Hurricane Ike made landfall near Galveston in mid-September. [NASA Earth Observatory] [NASA Earth Observatory]
Gulf Coast bays are vulnerable to flooding -- An oceanography professor at Rice University and colleagues at the University of North Carolina at Chapel Hill warn that the bays along the Gulf Coast from Texas to Alabama could be flooded rapidly and often during this century because of a combination of rising sea levels and the sediments from the number of dammed rivers. They think that the bays could reach conditions similar to those experienced earlier in the Holocene (9600 to 7000 years ago). [EurekAlert!]
Paleozoic "sediment curve" helps track movements of sea-floor sediments -- Geologists with the National Science Foundation and Murphy Oil International of Houston, TX claim that a new sediment curve showing where marine sediments have been deposited during the Paleozoic Era (542 to 251 million years ago) can be used to derive predictive models for the migration of sediments along continental margins and in interior seaways. [EurekAlert!]
Gas from ice cores help in climate reconstruction -- Geoscientists from Oregon State University who studied ice core samples obtained from the Antarctic ice at Byrd Station have found that the gas from bubbles entrained within the ice cores between 20,000 and 90,000 years ago indicates complex links between carbon dioxide levels, ocean currents and climate; the data from these ice cores are comparable to reconstructions from ocean sediment cores. [EurekAlert!]
Back when the Sahara was green -- Scientists from Germany's Center for Marine Environmental Research in Bremen and the Alfred-Wegener-Institute in Bremerhaven report that their reconstruction of the vegetation cover and the hydrologic cycle of Africa's Sahara and Sahel regions from a marine sediment core obtained from off the coast of Northwest Africa indicate three episodes during the past 120.000 years when the region occupied by the current Sahara Desert contained extensive grasslands, lakes and other water bodies. [Kiel University]
Ocean acidification and underwater sound transmission -- Marine chemists at the Monterey Bay Aquarium Research Institute have determined that acidification of seawater from increased dissolved carbon dioxide could permit sounds to travel greater distances underwater. They warn that projected increases in the oceanic acidity by mid century could allow sound to travel as much as 70 percent farther, possibly affecting the behavior of marine mammals. [Monterey Bay Aquarium Research Institute]
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, 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, including 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

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

Historical Events

7 October 1737...A furious cyclone in the Bay of Bengal caused a major disaster at the mouth of the Hoogby River near Calcutta, India. As many as 300,000 people were killed, mainly as the result of the storm's forty foot high surge. (Accord Weather Guide Calendar)
9 October 1873...LT Charles Belknap called a meeting at the Naval Academy to establish the U.S. Naval Institute for the purpose of disseminating scientific and professional knowledge throughout the U.S. Navy. (Navy Historical Center)
9 October 1967...A cyclone of relatively small dimension with a surface width of only 31 miles, hit India's coast at Orissa and moved to the northeast along the coast for 75 miles. As many as 1000 people and 50,000 head of cattle died. A surge in the storm's wake penetrated 16 miles inland. (Accord Weather Guide Calendar)
10-16 October 1780...The most deadly Western Hemisphere hurricane on record raged across the Caribbean Sea. This "Great Hurricane of 1780" killed 22,000 people on the islands of Martinique, St. Eustatius, and Barbados. Thousands more died at sea. (The Weather Doctor)
10 October 1845...Naval School, renamed the U.S. Naval Academy, opened in Annapolis, MD with 50 midshipmen students and seven faculty. (Navy Historical Center)
10 October 1861...Fridtjof Nansen, the Norwegian explorer, oceanographer, statesman, and humanitarian was born. Nansen led a number of expeditions to the Arctic (1888, 1893, 1895-96) and oceanographic expeditions in the North Atlantic (1900, 1910-14). He wrote The Oceanography of the North Polar Basin (1902). For his relief work after World War I, he was awarded the Nobel Prize for Peace in 1922. (Today in Science History)
10 October 1913...President Woodrow Wilson with the aid of a telegraph signal sent from Washington, DC triggered the demolition of the Gamboa Dike, allowing water to fill the Culebra Cut and create Lake Gatun, at 85 ft above sea level, the largest man-made lake at that time. This act signaled the completion of construction of the Panama Canal, which would eventually open to ship traffic between the Atlantic and Pacific Oceans on 14 August 1914. (Wikipedia, Today in Science History)
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)