WEEKLY OCEAN NEWS

DATASTREME OCEAN WEEK SIX: 28 February-4 March 2011

Ocean in the News

• Eye on the tropics ---
The tropical waters of the Southern Hemisphere remained active last week as boreal summer was drawing to a close. The following tropical cyclones were reported:
• In the South Indian Ocean basin, Tropical Cyclone Carlos, which had formed early the previous week as a tropical storm off the northern coast of Australia, moved southwestward across northwestern Australia late in that week before reforming along the continent's coast late last weekend. Continuing southwestward over the waters of the eastern Indian Ocean, this tropical storm briefly became a category 1 tropical cyclone on the Saffir-Simpson Scale late last week. Over this recent weekend, Carlos weakened to a tropical depression and was dissipating well off the coast of western Australia. For additional information on Tropical Cyclone Carlos including satellite imagery, consult the NASA Hurricane Page.
  Tropical Cyclone Dianne, which had reached a category 2 tropical cyclone status over last weekend, continued to travel to the southwest across the waters of the eastern Indian Ocean early in the week. However, by midweek this system had dissipated. The NASA Hurricane Page has additional information and satellite images on Tropical Cyclone Dianne.
• In the South Pacific basin, Tropical Cyclone Atu had intensified to become a major category 4 tropical cyclone on the Saffir-Simpson Scale late last weekend after formation near the island nation of Vanuatu during the week before last. Atu traveled to the south-southeast across the waters of the western South Pacific between New Caledonia and Fiji before dissipating late last week. An image made by the MODIS instrument onboard NASA's Aqua satellite shows the clouds surrounding Tropical Cyclone Atu early last week. [NASA Earth Observatory] [Editor's note: Since this tropical cyclone is in the Southern Hemisphere, the clouds appear to be circulating in a clockwise direction around the system, opposite the direction found in Northern Hemisphere counterparts, such as the hurricanes of the North Atlantic basin. EJH]
• Economic contributions of saltwater angling to be surveyed --
NOAA officials began a national survey of recreational saltwater anglers last week designed to update and improve the agency's estimates of the overall economic contributions that saltwater recreational fishing provides to the US economy. [NOAA News]
• Next step announced in the Gulf oil spill restoration process --
Early last week, NOAA and the US Department of Interior publicly announced plans to develop a Programmatic Environmental Impact Statement in cooperation with state co-trustees as part of the ongoing Natural Resource Damage Assessment in the Gulf of Mexico. This restoration process follows in the wake of last year's BP Deepwater Horizon Spill. [NOAA News]
• Scientists attempt explanation of baby dolphin deaths in Gulf --
Federal marine scientists are attempting to explain the rash of baby dolphin deaths in the northern Gulf of Mexico since the beginning of this year. However, a NOAA official advises that at present, these deaths should not be tied to last April's Gulf oil spill, as previous "unusual mortality events" in dolphins and manatees have been tied to coastal algae bloom ("red tide") toxins. [USA Today]
• Algae bloom in waters off New Zealand --
An image made over two weeks ago by the MODIS sensor on NASA's Aqua satellite shows a large phytoplankton bloom in the surface waters of the western South Pacific Ocean along New Zealand's South Island. [NASA Earth Observatory]
• Sea ice rings an island in the Kurils --
A natural color image obtained two weeks ago from the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite shows the annual sea ice formation around Ostrov Shikotan, a volcanic island at the southern end of the Kuril chain in the western North Pacific Ocean between Japan and Russia's Kamchatka Peninsula. [NASA Earth Observatory]
• Genetic code leading to harmful "brown tides" is cracked --
Researchers including those at the University of Tennessee, Knoxville and Oak Ridge National Laboratory have used genetic sequencing technique to crack the genome of a micro-organism species responsible for the Eastern Seaboard's notorious "brown tides", a harmful algal bloom. [University of Tennessee, Knoxville] [DOE Joint Genome Institute]
• More than two-thirds of Northeast's beaches are eroding --
A report released last week by the US Geological Society provides an assessment of changes along the coasts of the New England and Middle Atlantic States over the past 150 years and indicates that 68 percent of these beaches are eroding. However, the rate of erosion has decreased during the last 25 to 30 years. [USGS Newsroom]
• Offshore wind power generation proposed for Outer Banks --
County officials in North Carolina's Dare County were considering the building and testing of wind turbines offshore of Roanoke Island. Concern was voiced as to the proximity of these turbines to popular tourist beaches. [Outer Banks Voice] [Editor's note: Special thanks are extended to Terri Kirby Hathaway, AMS Oceans LIT Leader and Marine Education Specialist with North Carolina Sea Grant, for forwarding this article. EJH]
• Human health could be impacted within 30 years by climate change --
A panel of scientists attending last week's annual meeting of the American Association for the Advancement of Science unveiled new research that indicates how projected changes in climate over the next 30 years could increase exposure and risk of human illness originating from ocean, coastal and Great Lakes ecosystems. [NOAA News]
• Tiny marine creatures collected by famous Antarctic explorer used to monitor climate change --
Researchers from the British Antarctic Survey are beginning to study bryozoans, tiny marine animals, collected in the Ross Sea by the British explorer Robert Falcon Scott in 1901 in an effort to understand the impact of future climate change. They have found that polar carbon sinks in Antarctica have been increasing over the last century. [British Antarctica Survey]
• Ancient global warming events documented in the Arctic --
Scientists from the United Kingdom's University of Southampton have been studying marine sediment cores to ascertain environmental changes that occurred in the Arctic during the Paleocene–Eocene Thermal Maximum (PETM), an exceptionally warm period in Earth history approximately 56 million years ago. At that time, global sea surface temperatures increased by 5 Celsius degrees, causing widespread extinction of many foraminifera types, while plankton from tropical latitudes migrated poleward. [National Oceanography Centre]
• Plankton found to be a key to free oxygen in early atmosphere --
Analysis of isotopes stored in rock samples approximately 500 million years ago has permitted a researcher at Ohio State University and his colleagues to demonstrate how plankton provided for the release of a burst of free oxygen into the Earth's atmosphere at that time. Their study also details how oxygen nearly vanished from Earth's ancient atmosphere early in the Cambrian Period, only to return at higher levels. [Ohio State University]
• 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.

REPORT FROM THE FIELD -- George Rausch, an AMS DataStreme LIT Leader and a snow spotter for the North Webster (IN) National Weather Service Forecast Office, reported on this season's lake effect snow across southwestern Michigan and northern Indiana. Using a snowboard, he measured 78.33 inches from November through 20 February at his home in Benton Harbor, MI near Lake Michigan, which was more than 21 inches above normal. Two major lake effect events were responsible for this snowfall. He noted that this amount was more than the 64.25 inches of snow that had fallen to the same date last year. The bulk of the snow this year came between 5 January and 12 February when 58.7 inches fell. George also noted that South Bend, IN, approximately 30 miles south of Benton Harbor had received 98 inches or snow, or 38 inches above normal. Usually, Benton Harbor receives more lake effect snow than South Bend.

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

• 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)
• 5 March 1914...The Spanish ship the Principe de Asturias enroute from Barcelona to Buenos Aires sank with the loss of 445 of the 588 passengers and crewmembers when it struck the jagged reefs along the Brazilian coast at Ponta Boi in dense fog.
• 5-6 March 1962...The Great Atlantic Coast Storm of 1962 caused more than $200 million in property damage from Florida to New England. Winds along the Middle Atlantic Coast reached 70 mph raising 40-ft waves, and 42 inches of snow fell at Big Meadows, in the mountains of Virginia--a state record. The storm caused greater alteration of the coastline from Cape Hatteras, NC to Long Island than any previous storm, including hurricanes. A new inlet was cut through Hatteras Island and more than 10 miles of Outer Banks barrier dunes were obliterated. The Virginia shoreline was rearranged by historic tidal flooding caused by the combination of the long stretch of strong onshore winds and the spring tides. A 3-mile long boardwalk in Ocean City, MD was wiped out. (David Ludlum) (Intellicast)
• 6 March 1521...The Portuguese explorer Ferdinand Magellan reached Guam in his around the world voyage. (Wikipedia)
• 6 March 1987...The British ferry Herald of Free Enterprise capsized in the English Channel off the coast of Belgium with the loss of 189 people.

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Prepared by DS Ocean Central Staff and Edward J. Hopkins, Ph.D.,
email hopkins@meteor.wisc.edu
© Copyright, 2011, The American Meteorological Society.