The Blob (Pacific Ocean)

The Blob is an anomalous body having sea surface temperature much above the normal, seen here in a graphic of April 2014 by the NOAA.

The Blob is a large mass of warm water in the Pacific Ocean off the coast of North America.^[1] It was first detected in late 2013 and is expected to continue throughout 2015. It is unusual in ocean conditions and is considered to have a role in the formation of the unusual weather conditions felt in the Pacific Coast.^[1] The warm waters of the Blob are nutrient poor and have adversely affected marine life.

Origin

The Blob was first detected in the autumn of 2013 and the early months of 2014 by Nicholas Bond of the Joint Institute for the Study of the Atmosphere and Ocean of the University of Washington, and his colleagues, when a large circular body of sea-water did not cool as expected and remained much warmer than the average normal temperatures for that location and season.^[2]

Bond, who is the State Climatologist for Washington, coined the term "The Blob", with the term first appearing in an article in the monthly newsletter of the Office of the Washington State Climatologist for June 2014.^[3]

Description

The three "blobs" of warm water can be seen off the North American coast, ranging from Alaska to Mexico, seen in this graphic dated 1 September 2014.

Initially the Blob was reported as being 500 miles (800 km) wide and 300 feet (91 m) deep.^[1] It expanded and reached the size 1,000 miles (1,600 km) long, 1,000 miles (1,600 km) wide and 300 feet (91 m) deep, in the month of June 2014 when the term "The Blob" was coined.^[3][4][5] The Blob now hugs the coast of North America from Mexico to Alaska and beyond, over a stretch of 2,000 miles (3,200 km) and more, and has formed three distinct patches, the first, off the coast of Canada, Washington, Oregon, and California, a region known to oceanographers as the Coastal Upwelling Domain; the second off Alaska and in the Bering Sea; and the third and smallest, off Southern California and Mexico.^[2][6]

In February 2014, the temperature of the Blob was around 2.5 °C (4.5 °F) warmer than what was usual for the time of year.^[7] The Blob is expected to last at least until the end of 2015.^[4]

A NOAA scientist noted in September 2014, based on ocean temperature records, that the North Pacific Ocean never experienced temperatures this warm for so long.^[5]

Cause

The immediate cause of the phenomenon is the lower than normal rates of heat loss from the sea to the atmosphere, compounded with lower than usual water circulation resulting in a static upper layer of water. Both of these are attributed to a static high pressure region in the atmosphere, termed the Ridiculously Resilient Ridge which has existed since spring 2014.^[8] The lack of air movement impacts the wind-forced currents and the wind-generated stirring of surface waters. These in turn have influenced the weather in the Pacific Northwest from the winter of 2013–2014 onwards and may have been associated with the unusually hot summer experienced in the continental Pacific Northwest in 2014.^[7]

The reason for the phenomenon is unclear. Some experts consider that the wedge of warm water portends a cyclical change with the surface waters of the mid-latitude Pacific Ocean flipping from a cold phase to a warm phase in a cycle known as the Pacific decadal oscillation (PDO).^[1] This poorly-understood change happens at irregular intervals of years or decades. During a warm phase, the west Pacific becomes cooler and part of the eastern ocean warms; during the cool phase, these changes reverse.^[9] Scientists believe a cold phase started in the late 1990s and the arrival of the Blob may be the start of the next warm phase. The PDO phases may also be related to the likelihood of El Nino events.^[1]

NASA climatologist William Patzert predicts that if the PDO is at work here, there will be widespread climatological consequences and southern California and the American South may be in for a period of high precipitation, with an increase in the rate of global warming. Another climatologist, Matt Newman of the University of Colorado, does not think the Blob fits the pattern of a shift in the PDO. He believes the unusually warm water is due to the persistent area of high pressure stationary over the northeastern Pacific Ocean. Dan Cayan of the Scripps Institution of Oceanography is unsure about the ultimate cause of the phenomenon, but states "there's no doubt that this anomaly in sea surface temperature is very meaningful".^[1]

Effects

Marine life

Sea surface temperature anomalies are a physical indicator which adversely affect the zooplankton (mainly copepods) in the Northeast Pacific and specifically in the Coastal Upwelling Domain. Warm waters are much less nutrient-rich than the cold upwelling waters which were the norm till recently off the Pacific Coast.^[10] This results in reduced phytoplankton productivity with knock on effects on the zooplankton which feed on it and the higher levels of the food chain.^[7] The Northwest Fisheries Science Center, Seattle has predicted reduced catches of coho and Chinook salmon, a major contributing factor being the raised temperatures of seawater in the Blob.^[10]

Salmon catches in 2015 have dropped as the fish migrated away having found low levels of zooplankton.^[2] Thousands of sea lion pups are starving in California leading to forced beachings.^[11] Thousands of Cassin's auklets in Oregon have starved due to lack of food.^[11]

In addition, animals which favour warm waters and which have never been seen as far north as Alaska, have been spotted, examples being the warm water thresher sharks (Alopias spp) and ocean sunfish (Mola mola).^[5][11]

The discovery of a skipjack tuna (Katsuwonus pelamis), primarily a fish of warm tropical waters, off Copper River, in Alaska, 200 miles (320 km) north of the previous geographic limit, and a dead sooty storm-petrel (Oceanodroma tristrami), a species native to Northern Asia and Hawaii, along with a few brown boobies (Sula leucogaster) in the Farallon Islands of California, besides other such records, has led to worries amongst marine biologists that the food web across the Pacific is in danger of disruption.^[11]

Biologists from The University of Queensland observed the first ever mass bleaching event for Hawaiian coral reefs in 2014, and attributed it to the blob.^[12]

Weather and seasons

Research from the University of Washington found positive temperature anomalies in the NE Pacific Ocean (upper ~100 m, greater than 2.5 °C, with temperatures at the coast below normal) for the winter period of 2013–2014. Heat loss from the ocean during the winter time was suppressed. During spring and summer 2014 the warmer sea surface temperature anomalies reached coastal waters. The anomaly may have had a significant effect on the unusually warm summer of 2014, with record high temperatures over parts of land in the Pacific Northwest. Offshore sea surface temperatures (SSTs) in the NE Pacific for the month of February were the greatest at least since the 1980s, possibly as early as 1900. Additionally they found anomalous sea surface pressure SSP, with a peak magnitude approaching 10 hPa, a record high value for the years of 1949–2014.^[7]

Canadian senior climatologist David Phillips noted about the Alberta Canada winter season, "If that blob continues, if it stays warm ... and then you add to that El Nino, it may compliment each other and then it may be the year winter is cancelled."^[13]

See also

• Cold blob (North Atlantic)

References