Weekly Ocean News

DATASTREME OCEAN WEEK TWELVE: 27 November-1 December 2006

Ocean in the News:

(Thurs.) Supertyphoon Durian slams Philippines -- The fourth strong typhoon in four months has struck the Philippine Islands cutting off power to thousands and stranding travelers. Durian was packing winds to 119 mph with gust to 140 mph. [USA Today]
(Thurs.) Coral reefs at risk due to stormy seas -- Based upon the output from an engineering model, scientists at the University of California, Santa Barbara and James Cook University in Australia have warned that seas churned by increased storms and potentially large tsunamis could damage reefs around the world. [EurekAlert!]
(Thurs.) A mangrove forest seen from space -- An image obtained from NASA's Landsat 7 satellite shows the thick vegetation in the large Matang Mangrove Forest on the Malaysia Peninsula, surrounded by areas that have been cleared for agriculture and settlement. These mangrove forests that contain trees adapted to grow in a salty coastal environment can serve as a buffer against coastal erosion from strong storm systems and can be a nursery for marine life. [NASA Earth Observatory]
(Thurs.) Permian mass extinction produced dramatic shift in marine ecosystems -- Researchers at the Field Museum and at James Cook University claim that while the major mass extinction of species near the end of the Permian (approximately 250 million years ago) resulted in the demise of approximately 95 percent of the marine species, the event triggered a major shift in the ecology of the world ocean from domination by simple communities to complex ones. [EurekAlert!]
(Thurs.) Fossilized "nymph of the sea" studied -- An international team of scientists from the US and the British Isles discovered a crustacean fossil identified as an ostracod that contained approximately twenty eggs and two possible juveniles that were preserved in her soft anatomy as a result of volcanic ash approximately 500 million years ago. [EurekAlert!]
(Tues.) Downward trend in Arctic sea ice is noted -- A new analysis of satellite data made by experts at the U.S. National Ice Center indicates a steady decline in the extent of sea ice in the Arctic Ocean during the last 33 years. These data derived from a 1972 - 2004 chart series have become available in a new climatology data set, "New 30-Year Arctic Sea Ice Climatology" available to the research community. [NOAA News]
(Tues.) Greenland ice and snow shows signs of retreating -- Several images made from the MODIS instrument on NASA's Aqua satellite of a glacier in southeastern Greenland over a six-year span indicate a shrinkage of the glacier. These images confirm the results of a study made early this fall by NASA' s Gravity Recovery and Climate Experiment (GRACE) satellites that indicate loss of ice from the periphery of the ice, despite gains to the interior ice sheet. [NASA Earth Observatory]
(Tues.) Chesapeake Bay is reported to remain in poor health -- The Chesapeake Bay Foundation recently gave the nation's largest estuary failing grades for pollution, dissolved oxygen, water quality and underwater grasses important to help filter the water. However, the foundation found that the number of oysters increased over the previous year. [US Water News Online]
(Tues.) Ancient sunken treasure to be sold -- Approximately 150,000 items ranging from bowls to swords that were thought to be more than 1000 years old and retrieved less than two years ago from a sunken ship off the Java coast are to be sold. [BBC News]
(Tues.) Climate change affecting flows in submarine canyons -- Warming of ocean surface waters could decrease formation of denser waters and currents. These currents are a major player along with freshwater flows from land in bringing sediment to submarine canyons. [New Scientist]
Eye on the tropics --
- In the South Pacific Ocean basin, Tropical Cyclone Yani developed to the southeast of the Solomon Islands last week and moved toward the south, reaching an intensity of a Category 1 system on the Saffir-Simpson Intensity Scale. By the end of the week, this tropical cyclone had weakened to a tropical depression. An image obtained from the MODIS instrument onboard NASA's Terra satellite shows Tropical Cyclone Yani to the southeast of the Solomon Islands. [NOAA OSEI]
- In the western North Pacific, Tropical Storm Durian formed late last week approximately 1500 miles east of the Philippines. As of early Sunday, this tropical storm was continuing to move toward the west-northwest as it underwent slow intensification.
Underwater eruption viewed -- For the first time on record, a geologist at the University of Florida and colleagues were able to observe and record using sophisticated instruments an undersea volcanic eruption on the floor of the Pacific Ocean off the Mexican coast using the deep sea submersible Alvin. [EurekAlert!]
The scientists were able to witness the eruption because they were investigating why a marine geophysicist at the Lamont-Doherty Earth Observatory had lost two-thirds of her ocean bottom seismometers deployed along the East Pacific Rise. [EurekAlert!]
New East Coast ship routes are recommended to reduce ship-whale collisions -- Officials with the NOAA Fisheries Service are urging ship captains to use new routes when entering and leaving East Coast ports in northeastern Florida, Georgia and Cape Cod Bay in Massachusetts in an effort to reduce the chances of collisions between ships and endangered North Atlantic right whales. [NOAA News]
The 2006 hurricane seasons reviewed -- Although tropical storms and hurricanes could continue to form, the official 2006 hurricane season in both the North Atlantic and North Pacific will end this coming Thursday, 30 November 2006. [AMS DataStreme Atmosphere]
Deep-sea life found near methane seeps -- A team of scientists from New Zealand and the US have discovered deep-sea communities living around cold seeps on the ocean floor off the eastern coast of New Zealand near locations where methane or hydrogen sulfide escape. [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

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:

27 November 1703...The first Eddystone Lighthouse off the coast of Devon, England (approximately 14 miles southwest of Plymouth) was destroyed in the "Great Storm," and killed its builder Henry Winstanley. This first light was in an octagonal wooden structure built in 1698. The current structure is the fourth light to be constructed. The "Great Storm" is reported to have killed more than 8000 people. (Wikipedia) (Today in Science History)
27-28 November 1905... Heavy snow and wind blasted the western Great Lakes with as much as seven inches of snow in northwestern Wisconsin and sustained winds of 42 mph recorded at Duluth, MN for 29 straight hours and 65 mph winds for 13 continuous hours. Severe drifting resulted. Eighteen ships were destroyed or disabled on Lake Superior. The ship Mataafa was grounded and broke in two in Duluth harbor. Nine of the fifteen crew of the Mataafa froze to death despite running aground within 100 yards of the shore. (Accord Weather Guide Calendar)
28 November 1520...Portuguese navigator Ferdinand Magellan reached the Pacific Ocean after passing through the treacherous South American strait that now bears his name in a 38-day passage. He was the first European to sail into the Pacific Ocean from the Atlantic to the east. (The History Channel)
28 November 1960...A severe storm produced waves 20 to 40 feet high on Lake Superior. Duluth, MN was buried under a foot of snow, and clocked wind gusts to 73 mph. The northern shore of Lake Superior was flooded, and property along the shore was battered. Thousands of cords of pulpwood were washed into Lake Superior, and up to three feet of water flooded the main street of Grand Marais. Thunder accompanied the "nor'easter". (David Ludlum) (The Weather Channel)
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)