Weekly Ocean News

WEEKLY OCEAN NEWS

WEEK SIX: 14-18 October 2013

For Your Information

Opportunity for Teachers: The National Ocean and Atmospheric Administration's (NOAA) Teacher at Sea 2014 Field Season program is now accepting applications until the end of business on 31 October 2013. Gain your "sea legs" and first-hand experience in one-week to one-month voyages. For more information, or to apply, see http://teacheratsea.noaa.gov.
Biomixing in ocean motion -- If you would like information on recent findings that indicate marine organisms contribute to motion in the ocean, please read this week's Supplemental Information…In Greater Depth.
Celebrate Earth Science Week 2013 -- The National Oceanic and Atmospheric Administration, including the National Weather Service, along with NASA, the US Geological Survey and several professional scientific organizations such as the American Geological Institute have recognized next week (13-19 October 2013) as Earth Science Week 2013 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 15th annual Earth Science Week is "Mapping Our World", designed to engage "young people and the public in learning how geoscientists, geographers, and other mapping professionals use maps to represent land formations, natural resource deposits, bodies of water, fault lines, volcanic activity, weather patterns, travel routes, parks, businesses, population distribution, our shared geologic heritage, and more." [American Geological Institute]

Ocean in the News

Eye on the tropics --- Several named tropical cyclones developed across the ocean basins of the Northern Hemisphere during the last week:

In the North Atlantic basin, the remnant low that had been former Tropical Storm Karen continued to affect the weather along the Southeast and Middle Atlantic coasts of the United States through most of this past week. After weakening to a a post-tropical cyclone off the Louisiana Gulf Coast one week ago, this remnant low merged with a midlatitude cold front over the northeastern Gulf of Mexico by early Monday. Moving across the northern Florida Peninsula, the remnant low moved northward along the cold front to the coast of the Carolinas. While this system remained offshore for most of the week, strong onshore winds from the northeast brought locally heavy rain, coastal flooding and high surf to the Atlantic coast from the Carolinas northward to southern New England by late in the week.
In the eastern North Pacific basin, Tropical Storm Narda formed from a tropical depression approximately 950 miles to the southwest of Mexico's Baja California Peninsula. This fourteenth named tropical cyclone of the 2013 eastern Pacific hurricane season traveled toward the west-northwest during the first half of the week, eventually weakening to a tropical depression and then becoming a remnant low by last Thursday well off the Mexican coast.
Over this past weekend, Tropical Storm Octave formed approximately 470 miles to the south of Mexico's Baja California Peninsula. On Sunday Octave showed some strengthening as it traveled to the northwest off the Mexican coast. Current forecasts indicate that this tropical storm could curve toward the north and then northeast early this week, approaching the western coast of Baja.
In the western North Pacific basin, Typhoon Danas became Super typhoon Danas at the start of this past week as maximum sustained surface winds reached nearly 145 mph as it traveled toward the northwest passing near Okinawa; these winds made Danas a category 4 typhoon on the Saffir-Simpson Scale. During the week, Danas curved toward the north and then the north-northeast as it traveled across the East China Sea. By midweek, Danas weakened as it moved into the Korean Strait as a tropical storm.
A second strong typhoon called Typhoon Nari formed early last week and moved westward across the Philippine Sea becoming a category 3 typhoon as it moved across Luzon, the main islands in the Philippines. Crossing Luzon, Typhoon Nari weakened slightly, but brought heavy rain, winds to 125 mph and 30 to 40-foot waves around the island last Friday. On Saturday and Sunday, Typhoon Nari continued traveling west toward the coast of Vietnam near Da Nang. Landfall was expected along the Vietnam coast by Tuesday.
The third major typhoon that traveled across the western North Pacific last week was Typhoon Wipha that formed late last week from a tropical depression located to the west of Guam. Typhoon Wipha intensified to become a category 4 typhoon late Sunday (local time) as it traveled toward the northwest. Current forecasts indicate that Typhoon Wipha should curve toward the north and then to the north-northeast as it would approach southern Japan.
In the northern Indian basin, the first major tropical cyclone of the 2013 season for that basin formed near the end of last week. Named Cyclone Phailin, this system formed from a tropical storm near the Andaman Islands and traveled across the Bay of Bengal toward the northwest. As it traveled toward the eastern coast of India, Phailin intensified to become a category 5 tropical cyclone on the Saffir-Simpson Scale as maximum sustained surface winds exceeded 160 mph. By Sunday, this storm made landfall along the coast as one of the strongest tropical cyclones to hit India in decades. At least 14 fatalities were attributed to Cyclone Phailin. [CNN]

Georgia robot joins marine research project -- An underwater robotic glider called GliderPalooza that was created by the University of Georgia's Skidaway Institute of Oceanography has joined a fleet of more than a dozen other autonomous underwater robotic vehicles that are participating in a marine research project in the waters of the Atlantic coast. These gliders have collecting data on ocean conditions during the peak in the Atlantic hurricane season and designed to help NOAA scientists create improved hurricane intensity forecasts. [The Register-Guard]
Wave buoy deployed in Hawaiian waters to improve weather and ocean forecasts -- A 500-pound Pacific Islands Ocean Observing System (PacIOOS) wave buoy was recently deployed off the northern coast of the Hawaiian Island of Kauai that will measure ocean wave height, wave direction, wave period and sea surface temperature. This buoy was placed where it can collect data from large ocean swells that reach the Islands during the winter. These ocean data will be used to inform mariners and recreational boaters of coastal hazards and help provide information on transit times, as well as information on inundation forecasts for low-lying sections of the north-facing coasts. [The University of Hawaii System]
Explaining why sea ice around Antarctic is expanding while in Arctic sea ice is shrinking -- A recently produced Earth Gauge fact sheet describes the reasons why the sea ice around the Antarctic continent has been expanding over the last several decades while the sea ice covering the Arctic Ocean has shrunk to record minimum extent. [Earth Gauge]
Compaction of Nile Delta sediments is as important as rising seas -- A scientist at the Smithsonian Institution's National Museum of Natural History and colleagues from Italy claim that their analysis of subsurface sediments along Egypt's Nile Delta shows that subsidence rates due to compaction of these sediments are approximately four times greater than the rate of sea-level rise. This subsidence could cause the Nile Delta to be submerged within approximately 130 years. [ AGI Earth Magazine]
Slower spinning of Earth causes time problems -- As the rate of rotation of the Earth slows slightly by a few extra milliseconds per day during the last half century, accurate time-keeping instruments have to be readjusted to take into account the slight lengthening of the mean solar day. In addition to chronometers for time keeping, changes in the rotation rate affect GPS signals and other highly sophisticated devices. The slowdown of the Earth's spin rate is due to the Moon's gravitation and its affect upon the oceanic tides on Earth and upon the planet's interior. [The Sydney Morning Herald]
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]
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

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19 October 1843...Captain Robert Stockton of the Princeton, the first screw propelled naval steamer, challenged the British merchant ship Great Western to a race off New York, which Princeton won easily. (Naval Historical Center)
20 October 1892...After ten years of difficult and costly construction, the St. George Reef Lighthouse, built on a rock lying six miles off the northern coast of California, midway between Capes Mendocino and Blanco, was first lighted. (USCG Historian's Office)
20 October 1956...A German physician, Dr. Hannes Lindemann, began a voyage on which he would become the first person to cross the Atlantic in the smallest craft. Using a double-seat folding kayak that was 17 feet in length and outfitted with an outrigger and sail, he made the trip from Las Palmas in the Canary Islands to St. Thomas in the US Virgin Islands in 72 days. He had made a prior crossing in a 23-foot African dugout canoe. He later wrote a book, Alone at Sea, describing his experiences. (Today in Science History)
20 October 1984...The Monterey Bay Aquarium opened on Cannery Row in Monterey, CA as the largest artificial environment for marine life, housing 500 marine animals from at least 525 species. The aquarium also supports active research and conservation programs. (Today in Science History)
21 October 1797...The USS Constitution was launched at the Charlestown Navy Yard in Boston, MA. The ship, nicknamed "Old Ironsides," is now the oldest commissioned ship in the U.S. Navy. (Naval Historical Center)
21 October 1580...Portuguese navigator Ferdinand Magellan on his famous circumnavigation voyage of the globe reached Cape Virgenes and the strait at the tip of South America that now bears his name. Only three ships entered the 373-mile long passage separating Tierra del Fuego (land of fire) and the continental mainland. Navigating the treacherous strait in 38 days, the expedition entered the South Pacific Ocean, which Magellan named "Mar Pacifico" for the relatively tranquil seas that he found. However, one ship had been wrecked and another deserted. (The History Channel)
21-26 October 1998...Hurricane Mitch, a category 5 hurricane (on the Saffir-Simpson Scale), developed as a tropical depression over the southwestern Caribbean Sea about 360 mi south of Kingston, Jamaica on the 21^st. It would intensify over the next few days to become the second deadliest Atlantic hurricane on record, on the 24^th. By the 26^th, Mitch finally dissipated after remaining a category 5 hurricane for 33 hours. Estimated rainfall totals of up to 75 in. caused devastating flooding and mudslides in Honduras and Nicaragua for days. Estimated death toll from this hurricane was more than 11,000, the worst since 1780. (The Weather Doctor) (Accord Weather Calendar)