Weekly Ocean News

WEEKLY OCEAN NEWS

DATASTREME OCEAN WEEK SIX: 26 February-2 March 2007

Ocean in the News

(Thurs.) Field experiment studies air flow around Greenland ice cap -- Scientists from Britain, Norway, Iceland and Canada, including a physicist from the University of Toronto Mississauga, are participating in the Greenland Flow Distortion experiment (GFDex), an International Polar Year research project, that is attempting to monitor the role that the land and ice mass on Greenland plays in the atmospheric flow and Eurasian weather systems. One interesting feature is a "tip jet" that travels from Greenland to Iceland at speeds of up to 40 meters per second. This jet could affect the air-sea interaction, ultimately affecting water circulation in the Labrador Sea. [EurekAlert!] Scientists from the University of East Anglia in Great Britain are also involved with this project. [EurekAlert!]
(Thurs.) A big wave farm is considered -- Officials in Scotland have announced that a wave energy farm that they claim to be the world's largest is being planed for the Orkney Islands. [BBC News]
(Thurs.) Searching for life on icy Europa -- A paleobiologist from the University of California, Berkeley and colleagues have been attempting to search for life on Jupiter's moon Europa, which is thought to have a large ocean under an icy surface. [University of California, Berkeley]
(Thurs.) The missing crust -- Scientists from Cardiff University are probing the gap in Earth's crust under the Atlantic Ocean. Mantle rocks protrude to the surface off the Cape Verde islands. [BBC News]
(Thurs.) Clams are sequenced -- University of California Davis scientists have mapped the genome sequence of deep sea vent clams. [EurekAlert!]
(Tues.) High-altitude hurricane surveillance aircraft used in Pacific winter storms -- The NOAA Gulfstream-IV high-altitude jet that usually monitors hurricanes has been deployed to Honolulu, HI to collect atmospheric data from potent winter storms crossing the North Pacific Ocean as part of the 2007 Winter Storms Reconnaissance Program of the National Weather Service's National Centers for Environmental Prediction. This project is designed to help improve 24- to 96-hour forecasts of these storms that affect Hawaii, Alaska and the continental US. A middle school science and math teacher from Kona, HI will be a member of the flight crew as part of the NOAA Teacher in the Air program. [NOAA News]
(Tues.) A set of "ten commandments" could help improve fisheries management -- A zoology professor at Oregon State University proposed a list of "ten commandments" that he claimed could be used by fisheries managers as a part of an ecosystem-based management technique that could ensure a more sustainable catches in the future. [EurekAlert!]
(Tues.) Marine food chain could be threatened by more acidic ocean -- Marine scientists warn that increased air temperatures and rising atmospheric carbon dioxide concentrations across the globe could cause the world ocean to become more acidic, resulting in potentially catastrophic effects upon marine life, dissolving shells of marine organisms and destroying coral reefs. [National Geographic News]
(Tues.) Viewing Earth from space -- NASA officials have been posting a variety of images of the Earth along with atmospheric, oceanic and geologic data sets obtained from NASA satellites as part of the NASA Earth Observations (NEO) program. Samples of the imagery include those images obtained from the MODIS sensors on NASA's Aqua and Terra satellites of the chlorophyll concentrations of near surface waters, sea surface temperatures, cloud fraction and snow cover. [NASA Earth Observatory]
Tropical cyclone slams Mozambique -- A Southern Indian Ocean counterpart to a North Atlantic hurricane, Tropical Cyclone Favio, brought torrential rain and high winds to Mozambique late last week as it made landfall along the coast of this southeast African nation. This storm was rated a Category 4 on the Saffir-Simpson Intensity Scale. More than 120,000 people were made homeless from this tropical cyclone and several other earlier floods. [USA Today] An image obtained from the MODIS instrument on NASA's Terra satellite shows Tropical Cyclone Favio late last week before it made landfall in Mozambique. [NASA Earth Observatory]
International partnership struck on tsunami warning system -- Late last week NOAA and the Australian Bureau of Meteorology signed a cooperative partnership agreement that involves the deployment of a new Deep-ocean Assessment and Reporting of Tsunamis (DART™) buoy station in the Indian Ocean that would aid in early warning of tsunamis in that basin. [NOAA News]
Dangerous marine debris to be removed from Louisiana lake -- With aid from the NOAA Marine Debris Program, the Calcasieu Lake Marine Debris Marking and Mapping Program embarked on an effort involving the Louisiana Sea Grant College Program, state and local agencies, businesses and volunteers to remove nearly 100 pieces of marine debris from a vital estuary and shipping channel in southwest Louisiana that became a settling point for debris caused by Hurricane Rita in 2005. [NOAA News]
Bolivian floods prove deadly -- Torrential rains attributed to unseasonably warm sea surface temperatures in the eastern Pacific Ocean associated with an El Niño event have resulted in flooding and mudslides across Bolivia's eastern lowlands that caused 35 deaths, cut roads and affected approximately 69,000 families as of late last week. [USA Today]
Japanese ponder fate of disabled whaling ship -- The Japanese have yet to make a decision on what to do with their whaling vessel Nisshin Maru that was disabled by a fire and adrift in the Ross Sea off Antarctica. [BBC News] The New Zealand Conservation Minister along with conservation groups are demanding that Japan move the stricken vessel away from the Antarctic coast over a week after it caught on fire. [ENN]
Rapid ecosystem changes foreseen in the North Atlantic -- An oceanographer at Cornell University recently warned that increases in temperature that have affected the influx of fresh water from the Arctic along with a decrease in the cod fisheries have resulted in large, rapid changes in the ecosystems in the waters of the North Atlantic along the continental shelf from the Carolinas northward to Greenland. [Cornell University News]
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, cold but serene place where small particles rained gently downward and settled 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 131, 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

26 February 1935...Robert Watson-Watt demonstrated RADAR (Radio Detection and Ranging) for the first time, using the BBC shortwave radio transmitter to successfully detect the distance and direction of a flying bomber during the so-called Daventry Experiment.
26 February 1938...The first passenger ship was equipped with radar.
27 February 1949...Aerial ice observation flights by long-range aircraft operated from Argentia, Newfoundland. An International Ice Patrol by vessels was neither required nor established during the 1949 season, and it was the first time that aircraft alone conducted the ice observation service. (USCG Historian's Office)
27 February 1988...A major rain event occurred across Saudi Arabia's Foroson Islands in the Red Sea and on the adjacent mainland around Jizon when 1.15 in. fell. The monthly average rainfall is only 0.02 in. On the following day, flash flooding south of Riyadh killed three children. (Accord's Weather Calendar)
28 February 1849...Regular steamboat service to California from the East Coast via Cape Horn arrived in San Francisco for the first time. The SS California had left New York Harbor on 6 October 1848 on a trip that took 4 months and 21 days. (Wikipedia)
28 February 1964...A world 12-hour rainfall record was set at Belouve, La Reunion Island in the western Indian Ocean when 52.76 inches of rain fell. World records for 9 hours and 18.5 hours were also set with 42.79 and 66.49 inches, respectively. (Accord's Weather Calendar) (The Weather Doctor)
29 February 1504...Christopher Columbus used his knowledge of a lunar eclipse that night to convince Native Americans to provide him with supplies. (Wikipedia)
1 March 1498...The Portuguese explorer, Vasco de Gama, landed at what is now Mozambique on his way to India.
1 March 1854...The SS City of Glasgow left Liverpool harbor for Philadelphia and was never seen again with 480 people on board.
1 March 1902...The first regular light stations in Alaska were established at Southeast Five Finger Island and at Sentinel Island--both on the main Inside Passage between Wrangell Strait and Skagway. (USCG Historian's Office)
1 March 1905...The first regular light stations in Alaska were established. (USCG Historian's Office)
1 March 1927...A system of broadcasting weather reports by radio on four lightships on the Pacific Coast was put into effect. (USCG Historian's Office)
1 March 1970...US commercial whale hunting was ended.
1 March 1977...The United States extended its territorial waters to 200 miles.
1 March 1983...A ferocious storm battered the Pacific coast. The storm produced heavy rain and gale force winds resulting in flooding and beach erosion and in the mountains produced up to seven feet of snow in five days. An F2 tornado hit Los Angeles. Thirty people were injured and 100 homes were damaged. (The Weather Channel) (Intellicast)
3 March 1873...US Army Signal Corps established storm signal service for benefit of seafaring men, at several life-saving stations and constructed telegraph lines as original means of communication. (USCG Historian's Office)
3 March 1960...The submarine USS Sargo returned to Hawaii from an Arctic cruise of 11,000 miles, of which 6,003 miles were under the polar ice, reaching the North Pole on 9 February. This cruise marked the first time that a submarine explored the Arctic in winter. (Naval Historical Center)
4-5 March 1899...Tropical Cyclone Mahina (the Bathurst Bay Hurricane) crossed the Great Barrier Reef and generated a 48-ft storm surge across Barrow Point, Queensland, Australia. The Australian pearling fleet was destroyed, over 100 shipwrecks reported and 307 people killed. Barometric pressure fell to an unofficial reading of 915 millibars (27 inches of mercury). (Accord's Weather Calendar) (The Weather Doctor)