DATASTREME OCEAN WEEK TWELVE: 29 November-3 December 2004

• Another deadly tropical low pressure system hits the Philippines -- Within a week after Tropical Storm Muifa hit the main Philippine island of Luzon, Tropical Depression Merbok struck the island early last week with heavy rains that caused floods and landslides. At least 165 people were killed or remained missing and more than 30,000 homes were destroyed from these two tropical systems. [USA Today]
• New Arctic website unveiled -- A NOAA website called "Arctic Change" has been placed on line that focuses on the present and past state of the Arctic basin, with links to scientifically reputable sites for additional information on the Arctic's ice, land, climate and marine ecosystem. [NOAA News]
• Cores from Arctic Ocean seafloor reveal climate history --Members of the Arctic Coring Expedition have begun analyzing sediment cores obtained from the Arctic Ocean seafloor by the Integrated Ocean Drilling Program. These cores should help reveal the climate history of the region for the last 55 million years. [EurekAlert!]
• Award for tsunami warning system -- The US Department of Commerce gold medal has been awarded jointly to the Pacific Marine Environmental Laboratory and the National Data Buoy Center for their work on the development of DART (Deep Ocean Assessment and Reporting of Tsunamis), a new moored buoy system used to collect information for timely tsunami warnings. [NOAA News]
• Drifters and floats monitored hurricanes -- The data collected by specially designed instrumented floats and drifters dropped by aircraft into the paths of this season's hurricanes are now being analyzed. These instrumented platforms were part of a project called CBLAST (Coupled Boundary Layer/Air-Sea Transfer) that is aimed at focusing upon the energy exchanges between atmosphere and ocean during a hurricane. [EurekAlert!]
• Coupled models used to improve hurricane research--Physical oceanographers at the University of Rhode Island along with a group of international collaborators have utilized a coupled set of computer models that consider the atmospheric and oceanic conditions that develop around a hurricane. These scientists hope that the improved handling of wind-blown waves can help in improved forecasts of hurricane tracks and intensities. [EurekAlert!]
• Flame retardant chemicals found in Lake Michigan -- Researchers at the University of Wisconsin have reported finding large concentrations of flame-retardant polybrominated diphenyl ethers (PBDEs) in the sediments several hundred feet below the surface of Lake Michigan. [ENN]
• Withdrawal of Great Lakes water a concern --Proposals to divert fresh water from the Great Lakes to more arid sections of North America or to Asia have met with concern and opposition from various governmental and environmental groups in the states and Canadian provinces surrounding the Lakes. [ENN]
• Marine plankton could cool Southern Hemisphere -- A Dutch researcher recently reported that satellite observations of the distribution of marine phytoplankton suggest that these organisms could affect the climate of the Southern Hemisphere, with the release of dimethyl sulfide gas ultimately serving as condensation nuclei that could increase the cloud cover and result in the receipt of less sunlight at the earth's surface. [Netherlands Organization for Scientific Research]
• Coral reefs are endangered -- Scientists summarized the results to appear in the 2004 edition of "Status of Coral Reefs of the World" that indicate that 58 percent of the world's coral reefs are endangered. [ENN]
• Spill keeps offshore oil project from pumping -- A spill at Terra Nova off the Newfoundland coast at the beginning of last week has kept Canada's second-largest offshore oil project from resuming pumping operations. [ENN]
• Cost-effective tidal power envisioned--A British engineer believes that he can use existing turbine designs inside large underwater pipes to generate cost-effective tidal power. [EurekAlert!]
• Withdrawal of Great Lakes water a concern --Proposals to divert fresh water from the Great Lakes to more arid sections of North America or to Asia have met with concern and opposition from various governmental and environmental groups in the states and Canadian provinces surrounding the Lakes. [ENN]
• Fish refuges studied --Biological oceanographers at the University of Rhode Island recently reported on their study of several lagoons along Rhode Island's Atlantic seacoast. They found that eelgrass significantly helped the survival of certain fish and invertebrates in the lagoon from predation. [EurekAlert!]
• Marine mysteries probed-- Scientists from Scripps Institution of Oceanography and Indiana State University undertook a summer voyage last summer along Alaska's Aleutian Islands to investigate the causes of a major and devastating tsunami. While exploring the deep seafloor communities along the Aleutians with a remote submersible, they identified several previously undiscovered sea habitats. [Scripps Institution of Oceanography]
• Census of Marine Life expands database-- An international team of scientists from more than 70 countries have been cataloging and mapping marine species into the world's first Census of Marine Life. Within the last year, this database has been increased to include more than 5.2 million records that map the distribution of over 38,000 marine species. [EurekAlert!]
• An invasive species invades US waters--A team of scientists from NOAA, the US Geological Survey and the University of Rhode Island have announced that following their research cruise to Georges Banks in the North Atlantic, they found that sea squirts, a invasive type of tunicate, have invaded the US waters of this major offshore fishing ground. [EurekAlert!]
• 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: Climate Feedback Processes

Earth's climate system includes many interacting variables. Some variables are external to the Earth-atmosphere system and some are internal. External variables include solar energy output and Earth-sun geometry (i.e., the Milankovitch cycles). Internal variables include properties of the Earth's surface (e.g., albedo, moisture), the concentration of key atmospheric components (e.g., greenhouse gases, sulfurous aerosols), and cloud cover and thickness.

An important consideration in understanding how Earth's climate system responds to some perturbation is feedback. Feedback is defined as a sequence of interactions among variables in a system that determines how the system responds to some initial perturbation in one or more of the variables. Variables in Earth's climate system may interact in such a way as to either amplify (positive feedback) or lessen (negative feedback) a change in climate. An example of positive feedback is the ice-albedo effect described in Chapter 12 of the DataStreme Ocean textbook. Less ice cover in the Arctic greatly reduces the albedo of the Arctic Ocean causing higher sea surface temperatures and accelerated melting of the multiyear pack ice.

Consider an example of negative feedback. Increasing concentrations of atmospheric carbon dioxide enhances the greenhouse effect causing global warming. Global warming in turn raises sea surface temperatures and increases the rate of evaporation. A more humid atmosphere means more persistent and thicker cloud cover but clouds have both a cooling and warming effect on the lower atmosphere. The relatively high albedo of cloud tops causes cooling whereas absorption and emission of infrared radiation by clouds causes warming by contributing to the greenhouse effect. Satellite measurements and numerical models indicate that cooling would dominate.

In general, negative feedback tends to dominate over positive feedback in Earth's climate system, limiting the magnitude of climate change. The great thermal inertia of the ocean is the principal reason for dampening the planetary temperature response.

Concept of the Week: Questions

1. Feedback in Earth's climate system that amplifies climate change is described as [(positive)(negative)] feedback.
2. In general, [(negative)(positive)] feedback tends to prevail in Earth's climate system.

• 1 December 1969...Ocean swells generated by a storm more than 1000 miles to the north-northwest of the French Frigate Shoals produced 50-foot high surf along the outer shoals of Tern Island, submerging the 300-foot wide island under two to three feet of water. The 19-member Coast Guard contingent was evacuated, but considerable damage was done to buildings. (Accord Weather Calendar)
• 1 December 1990...Workers from the United Kingdom and France on the Channel Tunnel construction project met approximately 120 feet beneath the English Channel seabed, to establish the first ground connection between the British Isles and mainland Europe since the last Ice Age. (Wikipedia)
• 2 December 1755...The second Eddystone Lighthouse near Plymouth England was destroyed by fire. This light had replaced an earlier light that had been destroyed in the Great 1703 Storm". The current structure is the fourth light to be constructed at that site. (Wikipedia)
• 3 December 1952...A remarkable display of sea smoke was seen in Hong Kong harbor. The sea-smoke, induced by a strong surge of arctic air, poured from the water of Kowloon Bay from 8 AM to 9:30 AM. The air temperature near the sea wall was 44 degrees. (Accord Weather Calendar)
• 3 December 1992...The Greek oil tanker Aegean Sea carrying 80,000 tons of crude oil ran aground in a storm while approaching La Coruña, Spain, spilling much of its cargo. (Wikipedia)
• 3 December 1999...After rowing for 81 days and 2962 miles, Tori Murden became the first woman to cross the Atlantic Ocean by rowboat alone when she reached Guadeloupe after departing from the Canary Islands. (Wikipedia)
• 4 December 1786...The first of two great early December storms began. The storm produced high seas at Nantucket that did great damage. (David Ludlum)
• 4-13 December 1991...Tropical Cyclone Val with gusts to 150 mph caused $700 million damage. Seventeen deaths were reported in American and Western Samoa, with 95 percent of the housed in Savaii either destroyed or badly damaged. Savaii was essentially hit twice by Val as the system completed a loop on the 8^th. (Accord Weather Calendar)
• 5 December 1872...A British brigantine, the DeGratia, discovered the American ship Mary Celeste derelict and boarded her. The Mary Celeste, a brigantine had set sail from New York harbor for Genoa, Italy, on 5 November 1872. Everyone aboard the Mary Celeste had vanished-her captain, his family, and its 14-man crew. The ship, which appeared to have been abandoned for approximately nine days, was in perfect order with ample supplies and there was no sign of violence or trouble. The fate of the crew remains unknown. (Infoplease.com) (Wikipedia)
• 5 December 1492...The explorer Christopher Columbus became the first European to set foot on the island of Hispaniola, which now contains the countries of Haiti and the Dominican Republic. (Wikipedia)
• 5 December 1949...A typhoon struck fishing fleet off Korea; several thousand men reported dead. (Infoplease.com)
• 5-6 December 1968...High surf from an intense storm near Alaska swept rocks and seawater into pavilions at Onekahakaha Beach near Hilo, HI. Water reached 150 feet above high-tide mark at Napili Beach and swept into the swimming pool and ground floor of a hotel there. (Accord Weather Calendar)

Return to DataStreme Ocean Homepage

URL: DSOcean/news.html

Prepared by AMS DSOcean Central Staff and Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
ã Copyright, 2004, The American Meteorological Society.