A huge body of warm surface water along the West Coast, called "the blob", has nearly disappeared from satellite images, two years after it formed in the northeast Pacific Ocean.
El Niño’s strong winds and a series of winter storms helped cool and break down the 1,000-mile-wide mass of warm sea surface water.
“The original blob pattern has either lost its heat to the atmosphere, which basically warms the air and then effects the downstream conditions, or it was mixed into the underlying water,” said Art Miller, head of the oceans and atmosphere section at Scripps Institution of Oceanography.
Miller said remnants of the warm water extend down to a depth of 200 to 300 meters.
"The blob has sort of moved underneath the surface waters now and there’s warm conditions in the lower part of the upper ocean," Miller said. "We can actually see evidence of that in some of the remote observing systems we have floating around the Pacific.”
Researchers believe the blob evolved in fall of 2013, when a persistent ridge of high pressure weakened winds and stopped the circulation of the sea. The stagnant water heated and spread.
Sea surface temperatures soared as high as 7 degrees above normal. Fish and marine life suffered from a lack of nutrient-rich phytoplankton.
Miller said the extreme conditions serve as a preview of what’s to come.
“A lot of the excess heat that’s been trapped in the upper ocean these last couple years is very much like we would have expected under global warming conditions,” Miller said. “We expect things to be really warm in the upper ocean.”
Water temperatures are expected to return to normal when El Niño dissipates this summer.
“Under the assumption that a La Niña will follow a big El Niño,” Miller explained, “we would expect things to return to a highly productive ecosystem with cold water, lots of productivity and sort of back to the typical type of situation that we would see along our coast.”
