DATASTREME OCEAN WEEK TWELVE: 18-22 April 2011

Item of Interest:

• Celebrate Earth Day --
This Friday (22 April 2011) is the 41st Earth Day, first proposed by the late Senator Gaylord Nelson of Wisconsin in 1970 as a teach-in to heighten awareness of the environment. The Nelson Institute for Environmental Studies at the University of Wisconsin-Madison has posted a website called "Gaylord Nelson and Earth Day: The Making of the Modern Environmental Movement" that highlights Senator Nelson and his idea became Earth Day. A government website provides links to various activities and resources planned for this week.
• New York science center lauded by NOAA administrator --
Last Friday, NOAA Administrator Dr. Jane Lubchenco spotlighted NOAA's Cooperative Remote Sensing Science and Technology Center (CREST) at the City College of New York for its efforts to prepare high school and community college students for careers in science, technology, engineering, and math. CREST, which includes eleven post-secondary institutions in a five-state area and in Puerto Rico, is one of five cooperative science centers established by NOAA through the Educational Partnership Program (EPP) with minority serving institutions. [NOAA News]

Ocean in the News:

• Eye on the tropics --
Two tropical systems developed over the tropical waters in the Southern Hemisphere. In the South Pacific basin, a low-pressure system identified as System 93P formed northwest of New Caledonia. The NASA Hurricane Page provides information on System 93P and a low that formed in the South Indian Ocean basin called System 92S off the northern coast of Western Australia to the west of Darwin. Ultimately, this latter low organized to become Tropical Storm Errol at the end of the week. Over the weekend, Errol traveled to the northwest. For additional information and satellite imagery on Errol, please see the NASA Hurricane Page.
• The 2010 hurricane season reviewed --
The 2010 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]
• New rules issued to safeguard killer whales in Puget Sound --
Last week, NOAA's Fisheries Service issued new rules on vessel traffic that are aimed at protecting the endangered Southern Resident killer whales (or orca) in Washington State's Puget Sound. These rules will commence in one month. [NOAA News]
• Compliance assistance liaison named as outreach to Northeast fisheries --
NOAA recently announced appointment of Don Frei, a former commercial fisherman, as NOAA Office of Law Enforcement's compliance assistance liaison to continue outreach to the fisheries industry in Northeast. [NOAA News]
• Addition of Chinook salmon in Oregon rivers to threatened list considered --
Based upon a petition received from the Center for Biological Diversity, Oregon Wild, Environmental Protection Information Center and The Larch Company, NOAA's Fisheries Service recently announced that it make a decision on the placement of Chinook salmon in the Upper Klamath and Trinity Rivers basin as threatened or endangered under the Endangered Species Act. [NOAA News]
• Regulations governing Navy's activities in Washington State waters issued --
During the last week, NOAA's Fisheries Service has issued regulations and a letter of authorization to the US Navy that includes measures designed to protect marine mammals at the Naval Sea System Command Undersea Warfare Center Keyport Range Complex in waters off Washington State. [NOAA News]
• Global temperatures for March 2010 reviewed --
Using preliminary data collected from the global network of surface weather stations, scientists at NOAA’s National Climatic Data Center report that the combined global land and ocean surface temperature for March 2010 was the 13th highest for any March since global climate records began in 1880. They also reported that when considered separately, the average ocean and land temperatures were the 12th highest for March. La Niña conditions continued to contribute to the below average ocean temperatures across the central and eastern equatorial Pacific Ocean in March.
The researchers also noted the Arctic sea ice reached its annual maximum extent at the end of the first week of March, but the areal extent tied 2006 for the smallest annual maximum extent since satellite surveillance began in 1979. [NOAA News]
• Differing views of Gulf oil spill on first anniversary --
In polling conducted by the University of New Hampshire, residents of Louisiana and Florida were found to have differing views on the long-term effects resulting from the BP Deepwater Horizon disaster in the Gulf of Mexico one year after the oil rig explosion. Louisiana residents claimed more serious economic setbacks than Floridians and the former were more concerned with effects on fishing and oil industries, while the latter were concerned with tourism. [University of New Hampshire Media Relations]
• Great Lakes experience massive ecological changes due to invasive mussels --
A study conducted by the University of Michigan and NOAA's Great Lakes Environmental Research Laboratory reports "massive, ecosystem-wide changes" are currently occurring throughout Lakes Michigan and Huron because of the rapid spread of non-native mussels in the waters of the Laurentide Great Lakes. [University of Michigan News Service]
• Ocean "front" appears as an energetic contributor to mixing --
University of Washington and Stanford University researchers using three-dimensional surveys along an ocean "front", or a boundary between dissimilar water masses, report that turbulence forming along these fronts represents a potentially substantial source of energy for mixing of carbon dioxide downward into the ocean. Such information appears to be of import for inclusion in climate models. [University of Washington]
• Copepod carcasses show important link in marine ecosystems --
Researchers at the University of Maryland Center for Environmental Science and the Virginia Institute of Marine Science have found that the carcasses of copepods, multi-cellular marine organisms, found in water samples collected from Chesapeake Bay can provide insights into oceanic food webs and may provide insight into how these organisms respond to environmental change. [NSF]
• Humpback whale songs spread eastward across the ocean --
Researchers at Australia's University of Queensland and the South Pacific Whale Research Consortium have found that male humpback whales emit song patterns that typically spread from west to east across the Pacific Ocean from Australia east to French Polynesia. [EurekAlert!]
• Warmer surface waters in tropical Pacific could trigger West Antarctic warming --
Researchers at the University of Washington suggest that the rapid warming of the Antarctic Peninsula and West Antarctica during the last half century may have been the result of rising sea surface temperatures of the equatorial Pacific Ocean near the International Date Line. They claim that the warm equatorial waters drive an atmospheric circulation that has caused some of the largest shifts in Antarctic climate in recent decades. [University of Washington]
• Effect of black carbon upon climate change appears altitude-dependent --
Researchers at the Carnegie Institution for Science claim that how black carbon aerosols affect the climate depends on the altitude where these human-generated aerosols collect. They found that as the altitude of black carbon increased, surface warming is decreased, with black carbon inserted into the stratosphere causing a cooling of the underlying land and oceans. [Carnegie Institution for Science]
• Tectonic plate movement and earthquakes affected by climate change --
A team of Australian, French and German researchers report that they have found the strengthening of the Indian monsoon contributed to an accelerated movement of the Indian tectonic plate over the past 10 million years. Traditionally, tectonic plate movement is viewed as one of the factors responsible for climate change. [The Raw Story] [Editor's note: Special thanks goes to Terri Kirby Hathaway, LIT Leader and Marine Education Specialist for the North Carolina Sea Grant Program in Manteo, NC, for forwarding this article. EJH]
• 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, drought, floods, 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, to include 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.

Historical Events:

• 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)
• 23 April 1924...A tube transmitter for radio fog-signal stations, developed to take the place of the spark transmitters in use, was placed in service on the Ambrose Channel Lightship and proved successful. (USCG Historian's Office)
• 24 April 1884...USS Thetis, Bear, and Alert sailed from New York to search for Greeley expedition lost in the Arctic. (Naval Historical Center)
• 24 April 1928...The fathometer was patented by Herbert Grove Dorsey (No. 1,667,540). The invention measured underwater depths by using a series of electrical sounds and light signals. (Today in Science History)

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Prepared by AMS DS Ocean Central Staff and Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2011, The American Meteorological Society.