Weekly Ocean News

DATASTREME OCEAN WEEK TWELVE: 1-5 December 2008

Ocean in the News:

(Tues.) Venice floods -- Winds and tides combined to flood central Venice, Italy with its highest water in decades, 1.56 m (5 ft) above normal. Even the famous gondolas couldn't operate as the access docks were under water. Extensive damage to homes has occurred. [BBC News]
Eye on the tropics --- With the end of the official hurricane seasons in both the North Atlantic and eastern North Pacific basins, neither basin experienced tropical cyclone activity during the last week. Likewise, no activity was found across the western North Pacific. Only the tropical North Indian Ocean was active. The ninth tropical cyclone of 2008 in the Indian Ocean basin, Tropical Cyclone Nisha (or 6B), developed last week over the waters between Sri Lanka and India. Moving westward, this cyclone made landfall along the southeast coast of India. An image of the clouds surrounding Tropical Cyclone Nisha was made by the MODIS sensor on NASA's Terra satellite. More information can be obtained about Nisha on the NASA Hurricane Page.
The 2008 hurricane seasons reviewed -- Although tropical storms and hurricanes could continue to form, the official 2008 hurricane season in both the North Atlantic and North Pacific ended yesterday Sunday, 30 November 2008. [AMS DataStreme Atmosphere] Hurricane forecasters at NOAA's Climate Prediction Center suggest that the reason for the very active Atlantic hurricane season was a combination of several factors that included a the phase of a multi-decadal signal that favored increased hurricane activity; a lingering La Niña event; and above average tropical Atlantic sea surface temperatures at the height of hurricane season. [NOAA News]
Payment settles Alaska fisheries violations case -- NOAA’s Office of the General Counsel for Enforcement and Litigation recently announced that a settlement agreement was reached with a Seattle-based commercial fisheries company along with fishing ship captains for fisheries violations occurring from 2002 through 2004. [NOAA News]
Historic shipwreck found -- Maritime archaeologists from Ships of Discovery, an underwater archaeology research institute, recently announced that during a NOAA-supported diving mission in Atlantic waters off the Turks and Caicos Islands they discovered the wreck of the Spanish vessel Trouvadore, a historic slave ship that ran aground on a reef in 1842. [NOAA News]
Protection of bluefin tuna receives mixed signals -- Although the multinational International Commission for the Conservation of Atlantic Tunas failed to adopt measures championed by the United States that would end overfishing of bluefin tuna, the commission did adopt a strong measure advocated by the US that would rebuild the western Atlantic bluefin tuna stock. [NOAA News]
Mercury levels in red snapper could be raised by shrimp trawling -- Research conducted at Texas Christian University and Louisiana State University indicates the sharp reduction in the population of popular red snapper in the coastal waters of the Gulf of Mexico appears to be related to the shrimp trawling operations that have increased the level of toxic mercury in young snapper as the shrimp nets are dragged across and agitates deposits of mercury on the Gulf's floor. [EurekAlert!]
Monitoring the diet of humpback whales -- A team of researchers from the University of British Columbia, the University of California, San Diego and Cascadia Research Collective have been monitoring the eating habits of humpback whales, finding that these large marine mammals expend a large amount of energy as they forage for and consume zooplankton, some of the smallest prey. [EurekAlert!]
Ocean acidification grows at a rapid pace -- Scientists from the University of Chicago scientists claim that their research indicates the world's oceans are growing more acidic at a rate that is faster than previously thought. They have found that this increasing ocean acidity correlates with increasing concentrations of atmospheric carbon dioxide. [EurekAlert!]
Light pollution could affect coral reef health-- An international team of researchers from the US and Austria have developed the Lights Proximity Index that can be used to determine how the nighttime light pollution from urban areas, fishing vessels and oil/gas flares affects the health of coral reefs in the waters surrounding Puerto Rico, both directly and indirectly. [EurekAlert!]
Fishing activities may affect dolphin populations -- A study conducted by researchers at Scripps Institution of Oceanography and NOAA's Southwest Fisheries Science Center concludes that despite "dolphin safe" practices, fishing activities have had an adverse effect upon the population of at least one Pacific Ocean dolphin because of disruptions in the dolphins' reproduction output. [Scripps Institution of Oceanography]
Past climates could provide view of future -- A comprehensive reconstruction of the extremely warm mid-Pliocene period (3.3 to 3.0 million years ago) conducted by the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) group, which was led by the US Geological Survey, indicates that a sensitivity of the Earth's climate system to changes in atmospheric carbon dioxide levels, as well as to strong influences by ocean temperatures and heat transport away from equatorial regions. [USGS]
Predicting iceberg calving -- Researchers from Penn State University, Scripps Institution of Oceanography and several other academic institutions claim that they have derived a relationship that should improve their climate models in predicting where icebergs would calve from parent ice sheets. These researchers report that the rate at which ice shelves spread appears to be the most important variable in when an iceberg breaks, while other factors involve the width of the ice shelf and its thickness. [EurekAlert!]
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: 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

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

Historical Events:

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 Guide 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 F. (Accord Weather Guide 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 houses 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 Guide Calendar)
4 December 2003...A tropical depression became Tropical Storm Odette in the Caribbean well south of Kingston, Jamaica, becoming the first December tropical storm of record to form in the Caribbean Sea. Odette made landfall on near Cabo Falso, Dominican Republic on 6 December, causing eight deaths and destroying 35 percent of the banana crop. (Accord Weather Guide 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)
6 December 1830...The US Naval Observatory, the first U.S. national observatory, established as the Depot of Charts and Instruments in Washington, DC, under commander of Lieutenant Louis Malesherbes Goldsborough. Its primary mission was to care for the U.S. Navy's chronometers, charts and other navigational equipment. (Naval Historical Center)
7-8 December 1703...A monstrous storm raked southern England and adjacent waters with winds in excess of 100 mph. Approximately 8000 deaths were the result of this storm, mostly at sea. Many naval and supply ships were anchored in harbors or in the English Channel. The Eddystone Lighthouse disappeared. (Accord Weather Guide Calendar)
7 December 1872...An expedition put to sea from Sheerness aboard the corvette H.M.S. Challenger under the command of Captain George Nares on a 3 1/2-year world oceanographic cruise. During the 68,890 nautical mile cruise that ended on 24 May 1876, the ship traversed the North and South Atlantic and Pacific Oceans, traveled north of the limits of drift ice in the North Atlantic polar seas and south of the Antarctic Circle. The scientists onboard the Challenger sounded the ocean bottom to a depth of 26,850-ft, found many new species, and provided collections for scores of biologists. (Today in Science History)
7 December 1932...The first gyro-stabilized vessel to cross the Atlantic, the Conte di Savoia of the Italian Line, arrived in New York City. The ship had 48,502 gross tons, an overall length 814.6 ft by beam 96.1 ft, two funnels, two masts, four screws and a speed of 27 knots. As one of the first ships to be fitted with gyrostabilizers, it was claimed that rolling was limited to a maximum of three degrees. The maiden voyage began from Genoa to Villefranche and New York on 30 November 1932. (Today in Science History)