Weekly Ocean News

DATASTREME OCEAN WEEK TWELVE: 16-20 April 2007

Ocean in the News:

(Thurs.) Earthquakes could cause an increase in regional volcanic activity -- A scientist from the University of Hawaii and colleagues who analyzed MODIS data obtained from two NASA satellites have concluded that a major earthquake, such as the 6.4 magnitude earthquake on Java, could cause increased volcanic activity within the next week. [NASA Earth Observatory]
(Thurs.) Narwhal data gatherers -- Scientists from the U. of Washington's Polar Science Center and Greenland's Institute of Natural Resources are attaching satellite water profilers to deep-diving narwhals. These toothed whales make several soundings per day to depths of 3000 m with the temperature and depth data transmitted to satellites upon surfacing. The narwhals can provide profiles through the polar winters. [Wash. Post]
(Thurs.) A major marine migration monitored -- A recently published research report describes the annual migration that humpback whales undertake from their wintering area off Central America to feeding grounds off Antarctica, a distance of move than 5100 miles, which represents a record distance made routinely by a mammal. [EurekAlert!]
(Thurs.) Seafloor vents discovered on an ocean ridge -- Using the Autonomous Benthic Explorer from Woods Hole Oceanographic Institution, scientists have discovered active seafloor vents on the slowly spreading Southwest Indian Ridge on the floor of the Indian Ocean between the African and Antarctic tectonic plates. [Woods Hole Oceanographic Institution]
(Thurs.) Water debate tests Great Lakes compact -- A proposed regional compact that would protect Great Lakes water from being pumped to the water-starved Southwest is undergoing debate in the eight states surrounding the Lakes. [US Water News Online]
(Tues.) Satellite coverage of South America increased -- NOAA's GOES-10 satellite was repositioned in its geosynchronous orbit of the Earth to a new equatorial position over South America to provide residents of that continent with improved satellite coverage that would lessen the effects of natural disasters as part of the cooperation between NOAA in the US and counterpart agencies and organizations across the Americas as part of the Global Earth Observation System of Systems (GEOSS). [NOAA News]
(Tues.) Madagascar receives a soaking -- Recent images obtained from sensors on the Tropical Rainfall Measuring Mission (TRMM) satellite show the precipitation accumulated between 1 December 2006 and 5 April 2007 and the precipitation anomaly (difference between observed and average precipitation for the corresponding 1996 to 2006 interval) across Madagascar. Excessive precipitation across this region was the result of four tropical cyclones that drenched the island, the most recent making landfall in early April 2007. [NASA Earth Observatory]
(Tues.) Portrait of a potent midlatitude storm -- A visible image obtained from NOAA's GOES-11 satellite shows a major extratropical cyclone moving from the North Pacific toward the Gulf of Alaska and the Alaska coast late last week. This storm ultimately brought heavy precipitation and windy weather to the Pacific coast, from Alaska southward to Oregon. [NOAA OSEI]
(Tues.) Venice's future could be at mercy of high tides and climate change -- High tides and rising sea level cause by increased global temperatures could flood Venice, Italy and doom its future unless the complex system of floodgates called MOSES that are scheduled to become operational by 2012 can hold back waters from the Adriatic Sea. [Smithsonian Magazine]
(Tues.) Helping India prepare for sea level rise -- An international team of scientists that includes a coastal sciences professor from Louisiana State University is attempting to help India develop an environmental observation network and policies for coastal sections of that country that would mitigate the problems associated with projected rises in sea level. [EurekAlert!]
(Tues.) Soil erosion in Kenya documented by ancient coral reefs -- A scientist from Stanford University and his colleagues has found that coral reefs in the Indian Ocean can be used a proxy paleoclimatic record since these coral reefs can be used to detect 300 years of soil erosion from Kenya. [EurekAlert!]
High astronomical tides -- A combination of perigee (closest point in the lunar orbit of the Earth) and syzygy (the alignment of the sun, moon and Earth in a straight line at the time of new moon) on Tuesday should produce very high astronomical tides in most coastal locales.
The 2006 hurricane season reviewed -- The relatively benign 2006 hurricane season in the North Atlantic is reviewed and compared to the historic 2005 season when numerous long-standing records were broken during the most active hurricane season in the North Atlantic in over 150 years of record keeping. In addition to a review of this season in this basin, a review of the eastern North Pacific hurricane season was also made. [AMS DataStreme Atmosphere]
Hurricane awareness tour to commence -- With the approach of the 2007 hurricane season, the Director of NOAA's National Hurricane Center and a senior hurricane specialist will make a six-day and six-city tour of the Caribbean region onboard a US Air Force Reserve "Hurricane Hunter" aircraft to help raise public awareness of the threats associated with hurricanes. [NOAA News]
National Guard inventory not up to strength for hurricane season -- As the 2007 hurricane season approaches, state government officials in Florida are concerned that the inventory of National Guard equipment has been depleted by deployment to southwest Asia, thereby hampering a response to a potential natural disaster in the Sunshine State. [USA Today]
Hurricane forecaster critical of Gore's documentary -- Hurricane expert, Dr. William Gray of Colorado State University, recently criticized former Vice President Al Gore for being "a gross alarmist" in the production of documentary, "An Inconvenient Truth." Dr. Gray believes that the recent increase in the number of strong hurricanes is part of a long-term cyclic variation in ocean circulation patterns. [US Water News Online]
Coastal disasters due to hurricanes and tsunamis studied -- A research project funded by the National Science Foundation that has been focusing on the coastal erosion caused by the Indian Ocean Tsunami of 2004 and the Hurricane Katrina of 2005 has found certain surprising similarities. [EurekAlert!]
"Name NOAA's New Ship" winners announced -- The winners of "Name NOAA's New Ship" contest were five high school students and their biology teacher from Marina, CA who named the 208-foot fisheries survey vessel currently being built for NOAA "Bell M. Shimada" for a fisheries scientist who specialized in Pacific tropical tuna. [NOAA News]
Surveying arctic ice with a zeppelin -- A French physician has proposed a project to be developed by the Alfred Wegener Institute for Polar and Marine Research that would have a zeppelin airship equipped with sensors designed to measure ice thickness make a crossing of the Arctic Ocean from northern Canada over the North Pole to Siberia. [EurekAlert!]
Rogue wave hit Acapulco beach -- A large wave identified as a "rogue wave" swept into Acapulco Bay on Mexico's Pacific Coast early last week, washing over a coastal road and forcing six people to be rescued. [USA Today]
Complex mantle wedge structure could affect evolution of volcanic arcs -- Scientists at the University of California, Santa Cruz and Lawrence Livermore National Laboratory have been studying the complex structure of the mantle wedge along the major subduction zones that form the Pacific "rim of fire." They have found that this structure of the mantle wedge may affect the evolution of volcanic arcs in a complex way. [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 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:

16 April 1851...The famous "Lighthouse Storm" (a "nor'easter") raged near Boston Harbor. Whole gales and gigantic waves destroyed the 116-ft Minot Ledge Light at Cohasset, MA with the loss of its two keepers still inside. The lighthouse was the first one built in the United States that was exposed to the full force of the ocean. The storm coupled with a spring tide resulted in massive flooding, great shipping losses and coastal erosion. Streets in Boston were flooded to the Custom House. (David Ludlum) (US Coast Guard Historians Office) (Accord's Weather Guide Calendar)
16 April 1854...A furious storm that produced two feet of snow at New Brunswick, NJ also caused approximately 18 shipwrecks along the New Jersey coast. The immigrant ship Powhattan beached 100 yards from the shore. With rescue impossible, 340 people onboard lost their lives. "The shrieks of the drowning creatures were melancholy indeed." (Accord's Weather Guide Calendar)
16 April 1992...The Katina P ran aground off Maputo, Mozambique, causing 60,000 tons of crude oil to spill into the ocean. (Wikipedia)
17 April 1492...Spain and the Italian explorer Christopher Columbus signed a contract for him to sail to Asia to obtain spices. (Wikipedia)
17 April 1524...Giovanni Verrazano, a Florentine navigator, onboard the frigate La Dauphine "discovered" New York Bay. (Wikipedia)
18 April 1906...An early morning magnitude 7.8 earthquake along with a subsequent fire devastated much of San Francisco, CA, resulting in one of the worst natural disasters to hit a major US city. As many as 6000 people may have died because of this disaster. The earthquake was along the San Andreas Fault, with an epicenter thought to have been near Mussel Rock along the coast at suburban Daly City. [A series of articles commemorating the 100th anniversary of the San Francisco earthquake has been posted. San Francisco Chronicle]
18 April 1848...U.S. Navy expedition to explore the Dead Sea and the River Jordan, commanded by LT William F. Lynch, reached the Dead Sea. (Naval Historical Center)
19 April 1770...Captain James Cook discovered New South Wales, Australia. Cook originally named the land Point Hicks.
20 April 1534...Jacques Cartier, a French explorer, set sail from St. Malo, France with two ships to explore the North American coastline in an attempt to find a passage to China. In this first voyage, he explored the Gulf of St. Lawrence.
20 April 1952...The tankers Esso Suez and Esso Greensboro collided in thick fog off the coast of Morgan City, LA. Only five of the Greensboro's crew survived after the ship burst into flame. (David Ludlum)
21 April 1910...The U.S. Government took over sealing operation of Pribilof Islands in the Bering Sea from private lessees. (USCG Historian's Office)
21 April 1906...Commander Robert Peary, USN, discovered that the supposed Arctic Continent did not exist. (Naval Historical Center)
22 April 1500...Portuguese navigator Pedro Álvares Cabral became the first known European to sight Brazil, claiming it for Portugal. (Wikipedia)