Weekly Ocean News

DATASTREME OCEAN WEEK TWELVE: 14-18 April 2008

Ocean in the News:

(Thurs.) Clean up efforts of Biscayne Bay receives funding -- NOAA officials recently announced that the agency has provided $200,000 to aid Florida’s Miami-Dade County expand the scope of Baynanza, an annual celebration and cleanup of Biscayne Bay. [NOAA News]
(Thurs.) Public comment on effects of ship tests -- The NOAA’s Fisheries Service is seeking public comment on its proposal designed to minimize the US Navy's potential disturbance to marine mammals during sea testing of a new class of transport dock ship off the east coast of Florida this summer. [NOAA News]
(Thurs.) Coastal air pollution worsened by sea salt -- A group of researchers have found that sunshine along with airborne sea salt in coastal regions and along shipping lanes appear to make the pollution from urban areas and shipping markedly worse. [EurekAlert!]
(Tues.) A satellite comes to a rescue at sea -- Using the distress signal received by a NOAA satellite, the US Coast Guard and the Canadian Navy helped save 23 crew members onboard the Panamanian-flagged merchant vessel M/V Sea Venus that had an engine fire late last week approximately 1200 miles east of Cape Cod, MA. [NOAA News]
(Tues.) Seaweed in Sydney Harbor can be deadly -- A study by researchers at Australia's University of New South Whales report that seaweed in Sydney Harbor have very high levels of copper and lead contamination making them deadly to most sea creatures that feed on the seaweed. [EurekAlert!]
(Tues.) Winter's last stand in the Canadian Maritimes -- An image obtained at the start of last week from the MODIS sensor on NASA's Terra satellite shows sea ice remaining in eastern Canada's Gulf of St. Lawrence and snow across the surrounding Canadian Maritime Provinces, Quebec and Labrador [NASA Earth Observatory]
(Tues.) Arctic Ocean floor reveals ancient history --An expedition to the North Pole headed by a geoscientist from the University of Houston has found ancient rocks on the floor of the Arctic Ocean that date back two billion years and reveal a record of the planet's geological history involving complex processes involved with mantle formation. [EurekAlert!]
The 2007 hurricane season reviewed -- The 2007 hurricane season in both the North Atlantic and North Pacific is reviewed and compared to the more than 150 years of record keeping in the North Atlantic and the 40 years in the eastern North Pacific. [AMS DataStreme Atmosphere]
Hurricane forecast update -- Hurricane forecasters Dr. Philip Klotzbach and Professor William Gray from Colorado State University in Fort Collins recently issued an updated forecast of the upcoming 2008 North Atlantic hurricane season to the one they prepared last December. Their most recent April update calls for 15 named storms, including eight hurricanes, four of which could become major hurricanes. They also anticipate an above-average probability of a landfall on the mainland US. For these forecasts refer to [The Tropical Meteorology Project]
Gulf Coast hurricane awareness tour to begin -- The new Director of NOAA's National Hurricane Center and two hurricane specialists will make a five-day and five-city tour of the Gulf Coast region onboard a NOAA "Hurricane Hunter" aircraft this week to help raise public awareness of the threats associated with hurricanes. [NOAA News]
Virtual touring the National Hurricane Center -- NOAA's National Hurricane Center has unveiled a website that permits the public to take a virtual tour of the Center, with audio and text descriptions of the Center's activities in addition to the panoramic views of the facility located in Miami, FL. [NOAA News]
New radar technique adopted by hurricane forecasters -- During this upcoming summer, hurricane forecasters at NOAA's National Hurricane Center will use a new technique called VORTRAC (Vortex Objective Radar Tracking and Circulation) that was developed at the National Center for Atmospheric Research and the Naval Research Laboratory that relies on existing coastal Doppler radar units to continually monitor landfalling storms in the United States. [UCAR/NCAR] [NSF]
Listening for hurricanes -- Researchers at the Massachusetts Institute of Technology claim that placement of underwater microphones (hydrophones) in the path of an oncoming hurricane or tropical storm could be a relatively inexpensive means of determining the intensity of the tropical cyclone by determining the wind speed from the sound produced by the wind-generated froth in the surface water. [MIT News]
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:

14 April 1543...Bartolomé Ferrelo returned to Spain after assuming command of the ill-fated expedition of the Spanish navigator Juan Rodríguez Cabrillo (who died on San Miguel Island in California's Channel Islands). The expedition was the first known entry by Europeans into San Francisco Bay in the New World.
14-15 April 1912...The British steamer RMS Titanic sank following its collision with an iceberg in the North Atlantic off Newfoundland on its maiden voyage from South Hampton to New York. The collision occurred at about 11:45 PM on 14 April and the ship, which was considered unsinkable, sank in 2.5 hours during the early morning hours of the 15^th. Reports showed 1517 people out of 2207 onboard lost their lives in this accident. As a result of this disaster, certification and life saving devices were improved and an International Ice Patrol was established to monitor the iceberg hazards in the North Atlantic. The U.S. Coast Guard continues to conduct much of the effort. (US Coast Guard Historian's Office) A 21-year old telegraph operator at the Marconi radio station in New York City, David Sarnoff who became a pioneer in radio and television broadcasting, received and transmitted the distress calls from the Titanic. (Today in Science History)
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)