Weekly Ocean News

WEEKLY OCEAN NEWS

WEEK SIX: 12-16 October 2009

ITEMS OF INTEREST -

Celebrate Earth Science Week -- NOAA, including the National Weather Service, NASA, the US Geological Survey and several professional scientific organizations such as the American Geological Institute are recognizing this week (11-17 October 2009) as Earth Science Week. The goal of this week's celebration is to help the public gain a better understanding and appreciation for the earth sciences and to encourage stewardship of the Earth. This year's theme for the 11th annual Earth Science Week is "Understanding Climate", designed to "promote scientific understanding of a timely, vital topic: Earth’s climate." [American Geological Institute] [NASA GSFC]
An era of data collection from a satellite ends -- NASA scientists finally terminated the data collection from instruments onboard NASA's Earth Radiation Budget Satellite Experiment (ERBS) satellite after a 24-year span in which these instruments collected data about the Earth's atmosphere and climate. One of the important instruments on ERBS was the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument. [NASA Earth Observatory]

Ocean in the News

Eye on the tropics -- During the last week several tropical cyclones (low pressure systems that form over tropical or subtropical oceans) developed and traveled across tropical waters of the Atlantic and Pacific ocean basins:
- In North Atlantic basin, Tropical Storm Grace, the seventh named Atlantic tropical cyclone of 2009, formed over waters to the northeast of the Azores at the start of last week. After one day, this tropical storm, which was somewhat rare for the location, merged with an extratropical weather system after traveling to the northeast toward Ireland. The NASA Hurricane Page has additional information and satellite imagery on Grace.
  During the early week, Tropical Storm Henri formed over the central tropical Atlantic and traveled toward the west-northwest to approach the northern Leeward Islands. This system remained active for two days. Satellite images and additional information concerning Tropical Storm Henri can be found on the NASA Hurricane Page.
- In the eastern North Pacific basin, Tropical Storm Patricia, the fifteenth named tropical cyclone of the 2009 eastern Pacific hurricane season formed by early Sunday evening off the southwestern coast of Mexico. Patricia was traveling to the north.
- In western North Pacific Typhoon Parma, which had reached category 4 status on the Saffir-Simpson Scale over last weekend, caused problems over Luzon in Philippines before it moved out over the South China Sea and weakened to as tropical depression. However, as it approached Hainan Island and the Gulf of Tonkin Parma intensified again to a tropical storm as of Sunday. Flooding rain caused mudslides in the Philippines. See the NASA Hurricane Page for additional information, along with satellite images of Parma.
  Typhoon Melor, which became a supertyphoon (category 5 status of the Saffir-Simpson Scale) at the start of last week, during its travel toward the northwest across the western North Pacific near Guam, curved toward the north and then northeast during the early part of the week. By late in the week, this typhoon, which had weakened to a category 1 typhoon made landfall along the Japanese Archipelago. By the end of the week, Melor had become extratropical as it traveled northeastward across the North Pacific. Additional information on the former Typhoon Melor appears on the NASA Hurricane Page.
  Near the end of last week, Tropical Storm Nepartak formed near the Mariannas and traveled northward. As of early Monday (local time), Nepartak had turned toward the east. See the NASA Hurricane Page for additional information on this system.
National aquariums receive ocean education grants -- Last week, NOAA Education announced eleven grants had been made of more than $9 million to the nation's aquariums that will create new education projects at these aquariums designed to educate visitors about the ocean and encourage better stewardship of the marine environment. Some of these programs will have a theme that involves the ocean and climate change. [NOAA News]
Investigating how sea-level rises linked to climate could affect coastal areas -- Researchers at Florida State University have been investigating how anticipated rises in sea-level due to increased global temperatures, along with melting ice caps and increased storms could affect the infrastructure along the nation's low-lying coastal areas during the next century. [Florida State University]
New coastal map of the British Isles could help strengthen sea defenses -- Scientists from the United Kingdom's Durham University have published a mew "Coastland Map" that details the changes in the elevation of the United Kingdom due to isostatic adjustment since the last Ice Age, along with the current relative changes in sea level due to changes in global climate. Data obtained from this map could be used in planning for those coastal communities threatened by the projected changes in sea level during this century due to increased global temperatures. [EurekAlert!] A new study by researchers at the University of Southampton have found that sea levels have increased along the southern coast of England over the last century, making this coast more susceptible to coastal flooding during storms. [EurekAlert!]
Ship trails tracked by satellite -- An image made from data collected by the MODIS instrument on NASA's Terra satellite last week shows enhanced white trails in the marine clouds over the eastern North Pacific Ocean off North America's West Coast. These cloud tracks were caused by particulate matter in the ship exhaust that seeded the clouds and caused enhanced clouds. [NASA Earth Observatory]
Global oceans nourished by acidic clouds -- In research conducted at the United Kingdom's University of Leeds, scientists have proved that atmospheric acid helps decompose large particles of iron found in dust into extremely soluble small iron nanoparticles, which can be more readily used by plankton. With these iron nanoparticles falling from clouds with acidic particles, plankton growth can occur in the oceans, especially in iron-poor regions, thereby potentially triggering increased absorption of atmospheric carbon dioxide. [EurekAlert!]
Largest airborne polar ice survey to commence over Antarctica -- Later this week, NASA will begin a series of flights across Antarctica using the agency's DC-8 airborne laboratory as part of "Operation Ice Bridge," a six-year campaign designed to survey the sea ice, glaciers and ice sheets of Antarctica in the largest airborne survey of a polar region. [NASA] [EurekAlert!]
Catching feeding patterns of marine animals on camera -- Scientists from the British Antarctic Survey and Japan's National Institute of Polar Research and Hokkaido University who attached miniature digital cameras on the backs of black-browed albatrosses breeding on Bird Island, South Georgia have recorded how these albatrosses feed alongside killer whales in the Southern Ocean. [EurekAlert!]
Atmospheric carbon dioxide levels approach levels last found 15 million years ago -- Scientists at the University of California, Los Angeles, the California Institute of Technology and the United Kingdom's University of Cambridge report that their analysis of ancient marine algae shells using a new boron to calcium ratio shows that the last time atmospheric carbon dioxide levels were as high as at present occurred at least 15 million years ago. At that time, global temperatures may have been as much as 10 Celsius degrees above present and sea level 120 feet higher. [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: Abyssal Storms

Until recently, ocean scientists thought of the deep ocean abyss as a dark and cold, but serene place where small particles rained gently onto the ocean floor. However, instruments lowered to the sea floor to measure ocean motion or currents and resulting mobilization of bottom sediments detected a much more active environment. Scientists found that bottom currents and abyssal storms occasionally scour the ocean bottom, generating moving clouds of suspended sediment. A surface current of 5 knots (250 cm/sec) is considered relatively strong. A bottom current of 1 knot (50 cm/sec) is ripping. Although this may be called an abyssal storm, the water motion pales by comparison to wind speeds in atmospheric storms.

Abyssal currents and storms apparently derive their energy from surface ocean currents. Wind-driven surface ocean currents flow about the margins of the ocean basins as gyres centered near 30 degrees latitude. (Refer to Figure 6.6, page 152, in your textbook.) Viewed from above, these subtropical gyres rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. For reasons given in Chapter 6 of your textbook and this week's Supplemental Information, surface currents flow faster, are narrower, and extend to greater depths on the western arm of the gyres. These are known as western boundary currents and include, for example, the Gulf Stream of the North Atlantic basin. Abyssal currents are also most vigorous on the western side of the ocean basins, moving along the base of the continental rise, which is on the order of several kilometers deep.

Abyssal storms may be linked to or may actually be eddies (rings) that occasionally break off from the main current of the Gulf Stream (and other western boundary currents). During an abyssal storm, the eddy or ring may actually reach to the bottom of the ocean where the velocity of a bottom current increases ten-fold to about 1.5 km (1 mi) per hr. While that is an unimpressive wind speed, water is much denser than air so that its erosive and sediment-transport capacity is significant even at 1.5 km per hr. At this higher speed, the suspended sediment load in the bottom current increases by a factor of ten. Abyssal storms scour the sea floor leaving behind long furrows in the sediment. After a few days to a few weeks, the current weakens or the eddy (ring) is reabsorbed into the main surface circulation and the suspended load settles to the ocean floor. In this way, abyssal storms can transport tons of sediment long distances, disrupting the orderly sequence of layers of deep-sea sediments. Scientists must take this disruption into account when interpreting the environmental significance of deep-sea sediment cores.

Concept of the Week: Questions

In the subtropical ocean gyres, boundary currents flow faster on the [(western)(eastern)] side of an ocean basin.
Currents in an abyssal storm erode, transport, and redeposit sediments that have accumulated on the [(continental shelf)(deep ocean bottom)].

Historical Events

12 October 1492...Italian explorer Christopher Columbus sighted and landed on an island (possibly Watling Island) in the Bahamas during his travels westward across the Atlantic Ocean in search of an ocean route to eastern Asia. Apparently he underestimated the size of the world and assumed that he had reached East Asia after setting sail with three ships from Palos, Spain on 3 August 1492. During this expedition, which was the first known European expedition to the Americas since the 10^th century Viking colonies in Newfoundland, he sighted Cuba and landed on Hispaniola. (The History Channel)
12 October 1886...A hurricane made landfall between Sabine Pass, TX and Johnson's Bayou, LA. Waves were said to be as high as 2-story buildings. The surge extended 20 mi inland, with 150 people killed. Survivors clung to trees or floated on mattresses. Only two of 100 homes in Sabine Pass were reparable. (Accord Weather Calendar)
12 October 1954...Hurricane Hazel pounded Haiti and the island of Hispaniola with winds of 125 mph. Many villages were reported totally destroyed and more than 1000 Haitians died. (The Weather Doctor)
12 October 1965...End of Project Sealab II where teams of naval divers and scientists spent 15 days in Sealab moored 205 feet below surface near La Jolla, CA. (Navy Historical Center)
12 October 1979...The lowest observed sea-level barometric pressure (870 millibars or 25.69 inches of mercury) was recorded near Guam in the western Pacific Ocean at the center of Typhoon Tip. (The Weather Doctor)
13 October 1775...Birthday of U.S. Navy. The Continental Congress established the Continental Navy, later the U.S. Navy. (Naval Historical Center)
13 October 1884...The longitude that passes through the principal Transit Instrument at the Observatory in Greenwich, England was selected as the single universal meridian at the International Meridian Conference held in Washington, DC. A universal day was also selected. (Today in Science History)