WEEKLY OCEAN NEWS
18-22 October 2021
For Your Information
- International ShakeOut Day -- This Thursday, 21 October 2021, has been designated International ShakeOut Day, in which people and organizations around the world are encouraged to practice "Drop, Cover, and Hold On" to reduce injury and death during earthquakes. West Coast states that are prone to earthquakes, including California, Idaho, Oregon and Washington, are providing information on how to evacuate, survive and recover from tsunamis that could be generated along the coast by the earthquakes.
- Updated U.S. Climate Normals available in a user-friendly format -- Jan Null, a Certified Consulting Meteorologist with Golden Gate Weather Services, has compiled a set of downloadable pages that are designed to give quick, user-friendly access to both the monthly and daily normals of temperature, precipitation and snowfall for thousands of United States locations for the new 1991-2020 U.S. Climate Normals issued by NOAA's NCEI last May. Corresponding pages containing the U.S. Climate Normals for the previous 1981-2010 and 1971-2000 intervals are also available from this site. [Golden Gate Weather Services]
- Oceanographic expeditions that made an impact -- This week's Supplemental Information
... In Greater Depth provides a historical perspective of
some of the oceanographic expeditions that made an impact upon science,
especially in terms of oceanography.
Ocean in the News
- Eye on the tropics -- The weather across the tropical ocean basins of the Northern Hemisphere during the last week was relatively quiet as compared with previous weeks, as only three named tropical cyclones were found in the eastern and western sections of the North Pacific basin:
- In the eastern North Pacific basin (located off the western North American continent and extending westward to the 140-degrees West meridian) --
- Tropical Storm Pamela was strengthening rapidly last Monday morning as it traveled toward the west-northwest across the waters approximately 450 miles to the south-southeast of Cabo San Lucas, at the southern tip of Mexico's Baja California Peninsula. During the early morning hours of Tuesday, Pamela became the seventh hurricane of 2021 in the eastern North Pacific basin as maximum sustained surface winds reached an estimated 75 mph as it was approximately 265 mph south of Cabo San Lucas, Mexico. At the time, Hurricane Pamela was headed to the north. On Tuesday morning, Pamela reached peak intensity as a category 1 hurricane (on the Saffir-Simpson Scale) when maximum sustained winds reached 81 mph. Central minimum pressure had dropped to 985 mb (29.09 inches of mercury) as Pamela was 185 miles to the south-southeast of Cabo San Lucas. Pamela began weakening and was downgraded to tropical storm status as Air Force Reserve Hurricane Hunter aircraft found that winds had dropped to 70 mph as Pamela was 240 miles southwest of Mazatlán, Mexico. Traveling toward the northeast, Pamela passed close to Islas Marías, an archipelago of four islands located offshore of the western coast of the central Mexican mainland, on Tuesday evening. Strong winds, storm surge and torrential rains that were accompanying Pamela began spreading into west-central Mexico as Pamela. Early Wednesday morning, Pamela regained hurricane status as it was approaching the coastline. By dawn on Wednesday, Hurricane Pamela made landfall along the west-central coast of Mexico near Estacion Dimas, a community in the State of Sinaloa. Sustained winds at landfall were 75 mph. After making landfall, Pamela weakened to a tropical storm by midmorning on Wednesday as it crossed the mountainous terrain on a path toward the northeast. During the late afternoon, Pamela was further downgraded to a tropical depression. As of late Wednesday evening, Pamela finally dissipated over northeastern Mexico, approximately 110 miles west of Laredo, TX. Heavy rainfall accompanying the remnants of Pamela spread over sections of Texas and Oklahoma.
- In the western North Pacific basin (extending from the International Dateline westward to the Asian continent):
- Tropical Storm Namtheun, which had formed one week ago this past Sunday, was traveling toward the west-northwest to the south-southeast of Minami-Tori-shima, the Japanese coral atoll (also known as Marcus Island) early last Monday (local time). Maximum sustained winds were estimated to have been 50 mph. Strengthening occurred as it continued toward the west-northwest on Monday and into Tuesday, with sustained winds reaching 60 mph. Turning toward the north and then to the northeast, Namtheun weakened to tropical depression status on Wednesday, with winds dropping to 35 mph. However, Namtheun strengthened to become a tropical storm again on Thursday. Eventually, sustained winds surrounding Namtheun were estimated to have reached 75 mph on Saturday, making Namtheun a category 1 typhoon on the Saffir-Simpson Scale for a brief time this last Saturday. On Sunday, Namtheun had weakened to a minimal tropical storm with 40-mph sustained winds. As of early Monday morning, Tropical Storm Namtheun was tracking northward approximately 1130 miles to the northeast of Minami Tori-shima and was interacting with a midlatitude frontal boundary, which was causing it to lose its tropical characteristics.
- Tropical Storm Kompasu, the 24th tropical storm of 2021 in the western North Pacific basin, formed at the start of last week approximately 450 miles to the northeast of Manila, the capital of the Philippines. This system, which was traveling toward the northwest, was named Tropical Storm Kompasu. Over the next several days, Tropical Storm Kompasu curved and took a track toward the west passing just north of the Philippine Island of Luzon on Tuesday, but making a landfall near Fuga Island in the Philippine Province of Cagayan. The tropical storm then crossed the South China Sea toward China's Hainan Island. Early on Thursday, Kompasu had made landfall over the east coast of China's Hainan Island. After crossing the island, Kompasu headed across the Gulf of Tonkin as a tropical depression. As of late Thursday, Tropical Depression Kompasu was heading westward across the Gulf of Tonkin approximately 120 miles to the south-southeast of Hanoi, Vietnam. Sustained winds surrounding Kompasu had fallen to 30 mph. This system was becoming disorganized as it approached the coast of Vietnam, due to vertical windshear and entrainment of dry air. Kompasu made landfall by early Friday and became a remnant low as it moved across the mountainous terrain of Vietnam.
- September 2021 weather and climate for the globe reviewed -- Scientists at the NOAA National Centers for Environmental Information (NCEI) recently reported on their analysis of preliminary weather data collected from around the world during the month of September 2021. They found:
- The global combined land and ocean average surface temperature departure for September 2021 was 1.62 Fahrenheit degrees above the 20th-century average (1901-2000) temperature for the month of 59.0 degrees Fahrenheit. Consequently, the September 2021 global average temperature anomaly was the fifth highest September reading since a sufficiently dense network of global temperature records began in 1880. The record highest combined global September temperature departure was 1.69 Fahrenheit degrees that was reached four times in 2015, 2016, 2019 and 2020. Furthermore, the combined land-ocean temperature anomaly across the entire Southern Hemisphere for September 2021 was the highest September land-ocean temperature on record in that hemisphere, being 1.26 Fahrenheit degrees above the 20th century average. However, the corresponding combined land-ocean temperature anomaly across the Northern Hemisphere for last month was 1.96 Fahrenheit degrees, which was the fifth-highest anomaly for any September in 142 years.
When considered separately, the land surface temperature across the globe for this recently concluded month was the second highest September temperature in the 142-year record, with a monthly land-only global temperature that was 2.50 Fahrenheit degrees above the 20th-century average. The September record for air temperatures over land was set last year (September 2020), which had a temperature departure from the 20th century average of +2.65 Fahrenheit degrees. Over the oceans, the September 2021 globally-averaged sea surface temperature was 1.30 Fahrenheit degrees above the 20th century average, which was the sixth highest ocean-only global temperature anomaly on record for any September since 1880. The air just over the global ocean surfaces was the warmest in September 2015, with a record monthly temperature departure of +1.49 Fahrenheit degrees.
- According to data provided by the National Snow and Ice Data Center (NSIDC), the September 2021 Arctic sea ice extent in the Northern Hemisphere was approximately 23.2 percent below the 1981-2010 average, which was the twelfth smallest September Arctic sea ice extent since satellite records began in 1979; the smallest areal extent for September was in 2012. The sea ice cover reached its annual minimum extent on 16 September 2021, which was the twelfth lowest minimum seasonal extent in the 43-year period of record in the satellite era. In the Southern Hemisphere, the September 2021 Antarctic sea ice extent was slightly below average (-0.22 percent), making last month the 21st smallest (or 23rd largest) September extent on record; the annual maximum extent appears to have been reached on 1 September 2021.
- A global map of "Selected Significant Climate Anomalies and Events" for September 2021 is available from NCEI.
- A summary article on the September global climate highlights is available, while more detailed analysis with tables and maps can be viewed in NOAA/NCEI State of the Climate.
- According to NCEI’s Global Annual Temperature Rankings Outlook, the scientists feel virtually certain (greater than 99 percent) that 2021 will rank among the 10 warmest years on record, based upon current anomalies (through September) and historical global annual temperature readings. [NCEI Global Annual Temperature Rankings Outlook]
- Comparative El Niño and La Niña climatologies for October are updated -- Jan Null, a Certified Consulting Meteorologist with Golden Gate Weather Services, has updated his "Early October Comparative El Niño and La Niña Climatology (1997-1998 to 2021-2022)." Sets of "similar" ENSO (El Niño Southern Oscillation) warm and cool Sea Surface Temperature (SST) events were grouped using the NASA JPL Sea Height Anomaly products. He noted that the simple teleconnections that were thought to have been seen in the 1980s and 1990s do not appears as simple looking at the updated statistics. Very different outcomes are seen for the same categories of ENSO events. [Golden Gate Weather Services]
- El Niño/Southern Oscillation (ENSO) Diagnostic Discussion for October is released -- Forecasters at NOAA's Climate Prediction Center (CPC) and the International Research Institute for Climate and Society (IRI) released their monthly El Niño/Southern Oscillation (ENSO) Diagnostic Discussion late last week. They reported that La Niña conditions had remerged during September in both the oceanic and atmospheric components of the Earth system across the tropical Pacific Ocean.
Sea surface temperatures (SST) across those central and eastern-central sections of the equatorial Pacific to the east of the International Dateline were below-average. As of last week, the SST anomaly (departure from the long-term 1991-2020 average) in the region of the equatorial Pacific identified as the Niño3.4 sector was -0.6 Celsius degrees, which is beyond the threshold of -0.5 Celsius degrees considered as La Niña conditions for the oceanic component. Likewise, the SST anomaly for the Niño4 sector was -0.7 Celsius degrees. However, water temperatures were near-average in the eastern equatorial Pacific off the coast of South America, as the SST anomaly for the Niño1+2 sector ranging between -0.2 and +0.1 Celsius degrees. (Editor's note: CPC has a map of the four El Niño regions across the equatorial Pacific Ocean basin used to determine if El Niño or La Niña conditions are occurring. An El Niño is a "warm phase" event where above average SST values are found in the eastern equatorial Pacific, while a La Niña is a "cold phase" event with below-average SSTs in the eastern Pacific. EJH) SST values were slightly above-average in the far western equatorial Pacific surrounding Micronesia and New Guinea. Below-average temperatures also extended from the surface to a depth of approximately 300 meters in the central and eastern Pacific Ocean.
Atmospheric conditions especially involving near-surface and upper-level wind regimes across most of the basin were consistent with La Niña conditions last month. Low-level easterly trade winds (from the east) were prominent across the equatorial Pacific Ocean, while upper-level winds were westerly (from the west). Tropical convection was suppressed over sections of the central Pacific near and just west of the International Dateline, but enhanced over Indonesia. Furthermore, the Southern Oscillation Index (SOI) and Equatorial Southern Oscillation Index (ESOI), which are key atmospheric indicators of barometric pressure anomalies across the equatorial Pacific, were both positive, an indicator of La Niña. Positive SOI and ESOI indicate a strong Walker Circulation, which is a conceptual closed circulation cell model in the troposphere over equatorial regions of the Pacific, with sinking motions in the eastern regions and rising motions in the western regions.
Most of the two-dozen climate models used by CPC and IRI to generate the new outlook indicate that the current weak La Niña (with a Niño-3.4 index between -0.5 Celsius degrees and -0.9 Celsius degrees) should continue through boreal winter (December 2021-February 2022). The forecasters gave a 87 percent chance that La Niña conditions would continue through the boreal winter months. Therefore, the CPC's ENSO Alert System Status has been upgraded from a "La Niña Watch" to a "La Niña Advisory." Note: The criteria used for CPC's ENSO Alert System is available.
An ENSO blog for the Climate Watch Magazine was written by a scientist at the University of Miami's Cooperative Institute for Marine & Atmospheric Sciences where she describes in relatively plain terms showing why CPC and IRI forecasters have determined the return of La Niña, which ultimately leads to why they issued a La Niña Advisory. Using a decision flow chart, she explains that the SST anomaly values have dipped below the La Niña threshold in the region of the equatorial Pacific known as Niño 3.4 that is used to decide the existence of El Niño/La Niña. Furthermore, she clarifies how the atmospheric component over the tropical Pacific has developed into a La Niña version of the Walker Circulation regime featuring sufficiently strong easterly surface trade winds and westerly winds aloft that would maintain lower SSTs and the La Niña. Finally, she takes note of what a La Niña can mean for the outlook of the upcoming winter season across the U.S. [NOAA Climate.gov News]
A detailed and more technical El Niño/Southern Oscillation Diagnostic Discussion with supporting maps and charts is available from CPC.
Forecasters with the Australian Bureau of Meteorology recently issued an updated ENSO forecast from a Southern Hemisphere perspective in their "Climate Driver Update." They reported that surface waters of the tropical Pacific Ocean at the end of September were colder than average, which meant that La Niña conditions had developed in austral spring (September-November). In addition, the Indian Ocean Dipole (IOD), which affects Australian weather, has developed a negative index in September. (The IOD is an oscillation of sea surface temperatures across the Indian Ocean with a positive phase occurring when the western Indian Ocean has greater than average temperatures and above average precipitation, while a negative phase has above average SSTs along with above average rainfall in the east.) From their perspective, both La Niña and a negative IOD typically tend to increase the chance of above average rainfall across several wide sections of Australia during austral spring. Most of the international climate models used by the Australian forecasters, indicate La Niña conditions will continue during the upcoming Southern Hemisphere summer (December 2021 through February 2022). Therefore, the forecasters have raised their Bureau's ENSO Outlook to a "La Niña ALERT" as they see La Niña conditions have become established in the tropical Pacific and should persist through at least January 2022. [Australian Government Bureau of Meteorology]
- Center for Oldest Ice Exploration is funded at Oregon State University -- The National Science Foundation (NSF) recently announced that it is funding the Center for Oldest Ice Exploration (or COLDEX) at Oregon State University to discover Antarctica’s oldest ice and learn more about how the Earth’s climate has changed over the past several million years. COLDEX will be created under a five-year, $25 million Science and Technology Center award funded by NSF that will draw experts from across the nation. OSU is home to the Marine and Geology Repository, one of the nation’s largest repositories for oceanic sediment cores that also houses Antarctic ice core samples. Additionally, OSU has a growing polar science program. Thirteen other research universities will be collaborating with OSU in this project. [Oregon State University 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: 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
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).
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.
A 41-second mp4 video http://ametsoc.org/amsedu/ds-ocean/Seiche_Calculator.mp4 was produced providing a graphical simulation of a seiche by the University of Delaware's Seiche Calculator. The first demonstration on the video shows a case with the "Modal Number" set to 1 with a seiche in an enclosed basin. The second demonstration is for the "Modal Number" to 0.5, which would represent partially enclosed basins that usually have a node located at the mouth (rather than near the center) and an antinode at the landward end.
- 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)
- 18-19 October 2005...Hurricane Wilma developed a tiny, well-defined eye and began intensifying rapidly, reaching Category 5 strength with a record-setting pressure of 882 millibars (26.04 inches of mercury) by 19 October. The rapid intensification from tropical storm to Category 5 hurricane in 24 hours was the fastest ever recorded in the Atlantic Ocean, and the second-fastest worldwide, after Super Typhoon Forrest. (National Weather Service files)
- 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
- 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)
- 20 October 2004...Typhoon Tokage became the tenth typhoon to strike Japan that year. Rain accompanying this typhoon triggered flash floods that washed away entire hillsides, killing 55 people and leaving at least 24 people missing. (National Weather Service files)
- 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 21st. It would
intensify over the next few days to become the second deadliest
Atlantic hurricane on record, on the 24th. By
the 26th, 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)
- 22 October 1988...A "nor'easter" swept across the coast of
New England. Winds gusted to 75 mph, and large waves and high tides
caused extensive shoreline flooding. (The National Weather Summary)
- 22 October 2005...Isla Mujeres, Mexico set the Northern Hemisphere's and Western Hemisphere's 24-hour rainfall record with 64.33 inches thanks to Hurricane Wilma. (National Weather Service files)
- 23 October 1761...A violent hurricane struck New England, causing tremendous damage in Rhode Island and Massachusetts. (National Weather Service files)
- 23-24 October 1918...The Canadian steamship Princess
Sophia carrying miners from the Yukon and Alaska became
stranded on Vanderbilt Reef along coastal British Columbia. A strong
northerly gale hampered rescue attempts, and the next day, the ship
sank with the loss of the 268 passengers and 75 crewmen onboard. (The
- 24 October 1878: The Gale of 1878 was an intense Category 2 hurricane that was active between the 18th and 25th of October. It caused extensive damage from Cuba to New England, as was believed to be the strongest storm to hit the Washington - Baltimore region since hurricane records began in 1851. (National Weather Service records)
Return to Ocean Studies Maps & Links Page
Prepared by AMS Ocean Central Staff and Edward J. Hopkins,
© Copyright, 2021, The American Meteorological Society.