Weekly Ocean News

WEEKLY OCEAN NEWS

7-11 October 2019

For Your Information

Celebrate National Seafood Month -- The US Department of Commerce, along with one of its agencies, NOAA Fisheries, is celebrating this month of October 2019 as National Seafood Month. The public is invited to savor seafood during this month. A collection of short video clips of U.S. seafood can be viewed showing various aspects of the nation's sustainable fisheries. [NOAA Fisheries]
Fire Prevention Week -- This week (6-12 October 2019) is Fire Prevention Week across the nation, held in commemoration of the great Chicago (IL) and Peshtigo (WI) fires that occurred simultaneously on 8 October 1871. This year’s Not Every Hero Wears a Cape. Plan and Practice Your Escape™.”
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.

Ocean in the News

Eye on the tropics -- Tropical cyclone activity across the ocean basins of the Northern Hemisphere waned last week:
- In the North Atlantic basin (that includes the open North Atlantic, along with the Caribbean Sea and the Gulf of Mexico) --
  - Hurricane Lorenzo was a high-end category 2 hurricane on the Saffir-Simpson Scale as it was traveling to the north-northeast across the central North Atlantic last Monday. At that time, this fifth Atlantic hurricane of 2019 was located approximately 1000 miles to the southwest of the Azores. Lorenzo accelerated as it began curving to the northeast and headed toward the islands on Monday and Tuesday, while maintaining its strength. As of early Wednesday morning, Lorenzo had weakened to a category 1 hurricane as its central eye was approximately 55 miles to the north of Flores Island in the western Azores. Racing to the northeast away from the Azores on Wednesday, Hurricane Lorenzo lost its tropical characteristics and became an extratropical cyclone (midlatitude storm) by midafternoon. At that time, 80-mph maximum sustained surface winds were surrounding the center of former Hurricane Lorenzo as it was located approximately 945 miles to the west-southwest of Cork, Ireland. During its life-span, Lorenzo had become the easternmost major category 5 hurricane on a record that extends back more than 150 years, when maximum sustained surface winds reached 160 mph on the previous Sunday morning. As it traveled northward, the winds surrounding Hurricane Lorenzo generated ocean swells that propagated outward across most of the North Atlantic. Some of these ocean swells reached the East Coast of the U.S., resulting in high surf and rip currents that were responsible for as many as five drownings. The NASA Hurricane Blog and [Phys.org] have additional information and satellite imagery on Hurricane Lorenzo.
- In the eastern North Pacific basin (located off the western North American continent and extending westward to the 140-degrees West meridian) --
- In the western North Pacific basin (extending from the International Dateline westward to the Asian continent) --
  - Typhoon Mitag was heading toward the northwest across the waters of the western Pacific to the east of Taiwan and near the southern Ryukyu Islands at the start of last week. As it traveled, Mitag strengthened to become a category 2 typhoon (on the Saffir-Simpson Scale) late last Monday. However, Mitag weakening back to a category 1 typhoon on Tuesday as it crossed the East China Sea off the eastern coast of China. Typhoon Mitag made landfall on the southern coast of South Korea on Wednesday. Moving inland across the Korean Peninsula, it weakened into a tropical storm before becoming a remnant low as it traveled across the Sea of Japan. Strong winds associated with Mitag, along with torrential rains leading to flooding and landslides resulted in at least nine fatalities in South Korea. The NASA Hurricane Blog has satellite images and additional information on Typhoon Mitag.
  - A tropical depression, identified as Tropical Depression 20W, formed over the waters of the western North Pacific this past Saturday. TD-20W rapidly intensified to become Tropical Storm Hagibis by Sunday morning (local time) as it headed to the west. Heading toward Guam and the Mariana Islands on Sunday, Hagibis strengthened to become a category 1 typhoon, and then to a category 2 typhoon within four hours. As of Monday, Hagibis was continuing toward the west as it was approximately 320 miles to the east-northeast of Guam. Typhoon Hagibis was forecast to curve toward the northwest during this week.
NOAA Tide and Tidal Current Tables for 2020 are now available -- NOAA’s National Ocean Service announced last week that the NOAA 2020 Tide Tables and Tidal Current Tables are now available. These tide tables are official annual predictions of tides for approximately 3000 locations around the nation that have been generated by NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS) and its predecessor office for over 150 years. These tide tables that show the daily times and levels of high and low tides, along with the corresponding tidal current tables, are used by commercial and recreational mariners for safe navigation. These tables for 2020 are available online for U.S. coastal stations and some islands in the Pacific and Caribbean, for a time period of up to two years. With the availability of electronic predictions products, NOAA is ending the production of these printed publications with the final printed edition for the calendar year 2020. [NOAA National Ocean Service News]
New Gulf of Alaska sea floor maps reveal rich marine habitat -- Scientists from NOAA Fisheries and the U.S. Geological Survey have created new bathymetry charts for Alaska’s western Gulf of Alaska and the Shelikof Strait (to the west of Kodiak Island) that reveal the sea floor from the edges of the land masses down to a depth of approximately 7000 meters in the Aleutian Trench. These maps were generated by combining data obtained from historical National Ocean Service sounding information, shallow multibeam and LIDAR (light detection and ranging) data sets from the NOS and numerous soundings from multibeam surveys made during fisheries research cruises. This region off the Alaska Peninsula is a spawning ground for the Gulf’s biggest stock of walleye pollock and the mysterious Pacific sleeper shark species. The maps help scientists better understand the habitat requirements of many species and the oceanographic processes that influence their success. Furthermore, these new maps uncovered a rich record of glaciation with features that likely dated between 13,000 to 25,000 years ago. These features reveal the flow direction, extent and thickness of multiple glaciers. [NOAA Fisheries Feature Story]
A changing climate is literally causing a stink in south Florida -- A report made by Florida's Miami-Dade County Department of Regulatory & Economic Resources, the Miami-Dade County Water and Sewer Department and the Florida Department of Health predicts that within the next 25 years, 64% of the septic system tanks within the county could break and need repairs every year because of increased vulnerability to sea level rises and torrential downpours due to changing climate conditions across south Florida. Failure of these septic systems due to rising water table levels could result in contamination by untreated sewage or poorly treated effluent. Other coastal communities with large numbers of septic systems around the nation could also become vulnerable to rising water levels associated with climate change. [CNN News]
An All-Hazards Monitor-- This Web portal provides the user information from NOAA's National Weather Service, FAA and FEMA on current environmental events that may pose as hazards such as tropical weather, fire weather, marine weather, severe weather, drought and floods. [NOAA/NWS Daily Briefing]
Earthweek -- Diary of the Planet [earthweek.com]

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 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.

Historical Events

7 October 1737...A furious cyclone in the Bay of Bengal caused a major disaster at the mouth of the Hoogby River near Calcutta, India. As many as 300,000 people were killed, mainly as the result of the storm's forty-foot-high surge. (Accord Weather Guide Calendar)
7 October 1844...A major hurricane swept over Jamaica, Cuba, and the Bahamas. 158 vessels were wrecked and 2546 houses were destroyed along the Cuban coast. (National Weather Service files)
9 October 1804...The famous "Snow Hurricane" moved ashore along the New Jersey coast near Atlantic City on this day. After briefly passing through Connecticut and into Massachusetts, cool air was entrained in the circulation with heavy snow falling between New York to southern Canada. The Berkshires in Massachusetts and Concord, NH recorded two feet of snow with this hurricane. (National Weather Service files)
9 October 1873...LT Charles Belknap called a meeting at the Naval Academy to establish the U.S. Naval Institute for the purpose of disseminating scientific and professional knowledge throughout the U.S. Navy. (Navy Historical Center)
9 October 1967...A cyclone of relatively small dimension with a surface width of only 31 miles, hit India's coast at Orissa and moved to the northeast along the coast for 75 miles. As many as 1000 people and 50,000 head of cattle died. A surge in the storm's wake penetrated 16 miles inland. (Accord Weather Guide Calendar)
10-16 October 1780...The most deadly Western Hemisphere hurricane on record raged across the Caribbean Sea. This "Great Hurricane of 1780" killed 22,000 people on the islands of Martinique, St. Eustatius, and Barbados. Thousands more died at sea. (The Weather Doctor)
10 October 1780...The Great Hurricane of 1780 made landfall on the island of Barbados on this day with estimated wind gusts of 200 mph. This hurricane went on to affect the islands of St. Vincent where only 14 of 600 homes stood at Kings Town. St. Lucia, Martinique, Dominica, and Puerto Rico were all impacted from this hurricane. This is the deadliest Atlantic hurricane on record with between 20,000 and 22,000 deaths. (National Weather Service files)
10 October 1845...Naval School, renamed the U.S. Naval Academy, opened in Annapolis, MD with 50 midshipmen students and seven faculty. (Navy Historical Center)
10 October 1861...Fridtjof Nansen, the Norwegian explorer, oceanographer, statesman, and humanitarian was born. Nansen led a number of expeditions to the Arctic (1888, 1893, 1895-96) and oceanographic expeditions in the North Atlantic (1900, 1910-14). He wrote The Oceanography of the North Polar Basin (1902). For his relief work after World War I, he was awarded the Nobel Prize for Peace in 1922. (Today in Science History)
10 October 1913...President Woodrow Wilson with the aid of a telegraph signal sent from Washington, DC triggered the demolition of the Gamboa Dike, allowing water to fill the Culebra Cut and create Lake Gatun, at 85 ft above sea level, the largest man-made lake at that time. This act signaled the completion of construction of the Panama Canal, which would eventually open to ship traffic between the Atlantic and Pacific Oceans on 14 August 1914. (Wikipedia, Today in Science History)
10 October 2018...Hurricane Michael made landfall along the Florida Panhandle near Mexico Beach as a category 5 hurricane, as maximum sustained winds reached 160 mph. Central air pressure was 919 mb (27,14 inches of Hg), the third lowest reading for a U.S. landfalling hurricane. (National Hurricane Center)
11 October 1737...A deadly cyclone and storm surge of 42 ft raced up the Hooghly River in India and through the city of Calcutta destroying an estimated 40,000 boats and drowning as many as 300,000 people. (The Weather Doctor)
11 October 1846...One of the most intense Atlantic hurricanes of the 19th century ravaged Havana, Cuba and Key West, FL. At Havana the entire city was demolished and at Key West 594 of the town's 600 buildings were destroyed, with 5 feet of water reported in the city. The old Key West lighthouse and Fort Taylor were reduced to ruins. The storm eventually traveled up the entire U.S. East Coast and into the Canadian Maritimes. (Intellicast) (National Weather Service files)
11 October 1897...Property saved at Cape Hatteras, NC. During a severe storm, the surf threatened to wash away a fish house, with valuable nets and other gear. Surfmen saved the property and took it to a place of safety. They also assisted a lighthouse keeper by removing lenses from the beacon to a secure place. The lighthouse was in danger of being washed away by the sea. (US Coast Guard Historian's Office)
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 approximately 300 miles west of Guam in the western Pacific Ocean at the center of Typhoon Tip. This super typhoon had 190-mph winds. Gale force winds extended 1,350 miles out from the eye making it the largest tropical cyclone on record. (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)