Weekly Ocean News

DATASTREME OCEAN WEEK SEVEN: 15-19 October 2007

Ocean in the News:

(Thurs.) Project initiated to protect Oregon coast from harmful algal blooms -- NOAA's National Ocean Service has awarded a five-year project to Oregon State University, the University of Oregon and the Oregon Department of Fish and Wildlife help coastal Oregon communities monitor harmful algal bloom events and develop response plans designed to help minimize the impact of these events. This project is to be administered by NOAA's National Centers for Coastal Ocean Science. [NOAA News]
(Thurs.) American Rivers awarded funding for local restoration projects-- NOAA officials recently awarded the national organization, American Rivers, a grant worth more than $800,000 to continue its efforts at preserving streams and rivers across the Northeast, Mid-Atlantic, Northwest, and California so as to benefit a variety of fish species that migrate between salt and fresh water. [NOAA News]
(Tues.) Migration routes of humpback whales discovered -- An international team of scientists have implanted satellite tags in the blubber of South Pacific humpback whales as a means of tracking the whales' migration and daily habits. New whale migration routes have been discovered from this effort. [NOAA News]
(Tues.) Red Sea Volcano remains active -- The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite obtained an image of the Jebel at Tair volcano in the Red Sea and the thin volcanic plume emanating from it. [NASA Earth Observatory]
(Tues.) Dust from the Middle East spreads out over the ocean -- The MODIS instrument on NASA's Terra satellite captures airborne dust being carried by winds from the coast of the United Arab Emirates westward out over the Persian Gulf. [NASA Earth Observatory] The following day, a MODIS image shows dust being carried southward from the coasts of Iran and Pakistan out over the eastern Gulf of Oman and northwestern Arabian Sea. [NOAA OSEI]
Eye on the tropics ---
- In the North Atlantic basin, Tropical Depression 15 formed to the east of Bermuda late last week and moved initially east, before turning to the north. It became disorganized on Friday, well away from land areas. [USA Today] An image from NOAA's GOES-12 satellite shows clouds associated with TD-15 last Friday. [NOAA OSEI]
- No organized tropical cyclone activity was reported in the eastern North Pacific basin.
- In the western North Pacific basin, Tropical Storm Lingling formed on Saturday well to the east of the Asian Continent. As of late Monday (local time) this marginal tropical storm weakened into a tropical depression as it moved to the north-northwest.
Effects of typhoon flooding in Southeast Asia --Two images obtained nearly one week apart from the MODIS sensor on NASA's Terra satellite shows the rain-swollen rivers of northern Viet Nam and the sediment plume carried by these rivers into the Gulf of Tonkin because of the torrential rain that accompanied Typhoon Lekima at the beginning of October. [NASA Earth Observatory]
Another perspective of the record minimum Arctic sea ice -- An image of the record minimum extent of the sea ice cover obtained from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) on NASA’s Aqua satellite in September 2007 is compared with the coverage in 2005 when the previous record was set and for the median seasonal minimum for 1979-2000. [NASA Earth Observatory]
The official early winter outlook -- At the start of the second week of October, scientists at the Climate Prediction Center issued their first version of their official Winter Outlook for the three months from December 2007 through February 2008. Since they conclude that a La Niña event, an anomalous atmospheric and oceanic circulation regime that favors a colder than average equatorial eastern Pacific Ocean, has developed, they foresee that much the nation should have a better than even chance of experiencing above average temperatures. Only the Pacific coast, the Northwest, the northern Rockies and the northern Plains appear to have equal chances of having above or below average winter temperatures. They also claim that the southern US, extending from the lower Colorado River Valley eastward to the Atlantic Seaboard should expect a better than even chance of continued dry conditions this winter, meaning a possible intensification of the southern drought. Sections of the Northwest and the Midwest should see a better than even chance of above average winter precipitation. [NOAA News]
Celebrate Earth Science Week -- The National Oceanic and Atmospheric Administration, to include the National Weather Service, along with NASA, the US Geological Survey and several professional scientific organizations such as the American Geological Institute have recognized this coming week (14-20 October 2007) as Earth Science Week 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 10th annual Earth Science Week is "The Pulse of Earth Science", designed to promote public and professional awareness of the status of earth science in education and society. [American Geological Institute]
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: Seiche Model

A seiche (pronounced "say-sh") is a rhythmic oscillation of water in an enclosed basin (e.g., bathtub, lake, or reservoir) or a partially enclosed coastal inlet (e.g., bay, harbor, or estuary). With this oscillation, the water level rises at one end of a basin while simultaneously dropping at the other end. A seiche episode may last from a few minutes to a few days. (Refer to pages 156-157 in your textbook for more on seiches.)

With a typical seiche in an enclosed basin, the water level near the center does not change at all but that is where the water exhibits its greatest horizontal movement; this is the location of a node. At either end of an enclosed basin, vertical motion of the water surface is greatest (with minimal horizontal movement of water); these are locations of antinodes. The motion of the water surface during a seiche is somewhat like that of a seesaw: The balance point of the seesaw does not move up or down (analogous to a node) while people seated at either end of the seesaw move up and down (analogous to an antinode).

Go to the University of Delaware's Seiche Calculator at http://www.coastal.udel.edu/faculty/rad/seiche.html. Set the "Modal Number" to 1 and then press "Calculate" for a graphical simulation of a seiche in an enclosed basin.

Partially enclosed basins usually have a node located at the mouth (rather than near the center) and an antinode at the landward end. Go to the Seiche Calculator, set the "Modal Number" to 0.5 and then press "Calculate" for a simulation of a seiche in a basin open to the right. Furthermore, some basins are complex and have multiple nodes and antinodes; these can be simulated on the Seiche Calculator by selecting different values of "Modal Number" greater than one.

The natural period of a seiche depends on the length and depth of the basin and generally ranges from minutes to hours. The period is directly proportional to basin length. For example, the natural period of a seiche in a small pond is considerably less than its period in a large coastal inlet. Also, for the same basin, the natural period is inversely proportional to water depth; that is, the period shortens as water deepens. Using the Seiche Calculator, you may wish to experiment with different basin lengths and depths. Conversely, one can determine the average depth of a lake by determining the period of the seiche and the length of the lake.

Concept of the Week: Questions

In an enclosed basin the node of a seiche is located [(at either end) (near the center)] of the basin.
The natural period of a seiche [(depends on) (is independent of)] the size of an enclosed basin.

Historical Events:

15 October 1947...A hurricane made a hairpin turn off the Georgia coast after being seeded with dry ice. The storm passed over Savannah and tracked inland through Georgia. (Intellicast)
15 October 1954...Hurricane Hazel struck the Carolina coastline near Cape Fear, NC. The hurricane (category 4 on the Saffir-Simpson Scale) demolished every pier along a 170-mile stretch from Myrtle Beach, SC to Cedar Island, NC, and obliterated rows of beach homes. At Long Beach, 300 homes vanished; no debris remained. Hurricane Hazel also destroyed 1500 homes as it made landfall with 17-ft tides. Winds between Myrtle Beach, SC and Cape Fear, NC gusted to 150 mph. Later, the remnants of Hazel moved northward into Ontario and became the most remembered storm in Canadian history. Winds gusted to 75 mph and as much as 7.2 inches of rain fell. Eighty people died, mostly from flooding in the Toronto area (David Ludlum) (The Weather Channel) (The Weather Doctor)
15 October 1999...A waterspout (a tornado over water) moved onshore at Fort Lauderdale Beach, FL and blew out a plate glass window in a bar, injuring 8 patrons. The waterspout also overturned a vehicle and caused other significant damage on Los Olas Blvd. (Accord Weather Calendar)
16 October 1877...Bjørn Helland-Hansen, the Norwegian pioneer of modern oceanography, was born on this date. His studies of the physical structure and dynamics of the ocean were instrumental in transforming oceanography from a descriptive science to one based on the principles of physics and chemistry. (Today in Science History)
17-20 October 2004…Humid air from a former typhoon east of Japan helped deepen low pressure to 941 mb over the Gulf of Anadry west of Nome, AK (18th). Winds between 50 and 80 mph, with an unofficial gust to 114 mph at Red Dog Mine on the 19th, raked western Alaska. Storm surges reached approximately 11 feet. As much as $19.9 million in damage resulted from this storm. (Accord Weather Guide Calendar)
18 October 1910...Northeasterly winds as high as 70 mph (from a hurricane moving northward up the Florida peninsula) carried water out of Tampa Bay and the Hillsboro River. The water level lowered to nine feet below mean low water. Forty ships were grounded. (The Weather Channel)
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 Bianco, 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)