‘The Blob’ overshadows El Nino

El Niño exerted powerful effects around the globe in the last year, eroding California beaches; driving drought in northern South America, Africa and Asia; and bringing record rain to the U.S. Pacific Northwest and southern South America. In the Pacific Ocean off the West Coast, however, the California Current Ecosystem was already unsettled by an unusual pattern of warming popularly known as “The Blob.”

New research based on ocean models and near real-time data from autonomous gliders indicates that the “The Blob” and El Niño together strongly depressed productivity off the West Coast, with The Blob driving most of the impact.

The research published in the journal Geophysical Research Letters by scientists from NOAA Fisheries, Scripps Institution of Oceanography and University of California, Santa Cruz is among the first to assess the marine effects of the 2015-2016 El Niño off the West Coast of the United States.

“Last year there was a lot of speculation about the consequences of ‘The Blob’ and El Niño battling it out off the U.S. West Coast,” said lead author Michael Jacox, of UC Santa Cruz and NOAA Fisheries’ Southwest Fisheries Science Center. “We found that off California El Niño turned out to be much weaker than expected, The Blob continued to be a dominant force, and the two of them together had strongly negative impacts on marine productivity.”

“Now, both The Blob and El Niño are on their way out, but in their wake lies a heavily disrupted ecosystem,” Jacox said.

Unusually warm ocean temperatures that took on the name, The Blob, began affecting waters off the West Coast in late 2013. Warm conditions – whether driven by the Blob or El Niño – slow the flow of nutrients from the deep ocean, reducing the productivity of coastal ecosystems. Temperatures close to 3 degrees C (5 degrees F) above average also led to sightings of warm-water species far to the north of their typical range and likely contributed to the largest harmful algal bloom ever recorded on the West Coast last year.

 Wintertime temperature anomalies off the US west coast during the strong El Niños of 1997-98 and 2015-16. In 1997-98 warming was strongest near the coast, consistent with effects of El Niño. In 2015-16, warming was more uniform and widespread, consistent with pre-existing warming known as ‘the Blob.’ Credit: Michael Jacox

 

“These past years have been extremely unusual off the California coast, with humpback whales closer to shore, pelagic red crabs washing up on the beaches of central California, and sportfish in higher numbers in southern California,” said Elliott Hazen of the Southwest Fisheries Science Center, a coauthor of the paper. “This paper reveals how broad scale warming influences the biology directly off our shores.”

The research paper describes real-time monitoring of the California Current Ecosystem with the latest technology, including autonomous gliders that track undersea conditions along the West Coast. “This work reflects technological advances that now let us rapidly assess the effects of major climate disruptions and project their impacts on the ecosystem,” Jacox said.

Separate but related research recently published in Scientific Reports identifies the optimal conditions for productivity in the California Current off the West Coast, which will help assess the future effects of climate change or climate variability such as El Niño. The research was authored by the same scientists at UC Santa Cruz and NOAA Fisheries.

“Wind has a ‘goldilocks effect’ on productivity in the California Current,” Hazen said. “If wind is too weak, nutrients limit productivity, and if wind is too strong, productivity is moved offshore or lost to the deep ocean. Understanding how wind and nutrients drive productivity provides context for events like the Blob and El Niño, so we can better understand how the ecosystem is likely to respond.”

Both papers emphasize the importance of closely monitoring West Coast marine ecosystems for the impacts of a changing climate. Although the tropical signals of El Niño were strong, the drivers – called “teleconnections” – that usually carry the El Niño pattern from the tropics to the West Coast were not as effective as in previous strong El Niños.

“Not all El Niños evolve in the same way in the tropics, nor are their impacts the same off our coast,” said Steven Bograd, a research scientist at the Southwest Fisheries Science Center and coauthor of both papers. “Local conditions, in this case from the Blob, can modulate the way our ecosystem responds to these large scale climate events.”

Explore further: ‘Warm blob’ in Pacific Ocean linked to weird weather across the US

More information: Michael G. Jacox et al, Impacts of the 2015-2016 El Niño on the California Current System: Early assessment and comparison to past events, Geophysical Research Letters (2016). DOI: 10.1002/2016GL069716

Read the original post: http://phys.org/news/2016-07-blob-overshadows-el-nino.html

Possible Spoiler for El Niño: A ‘Battle of the Blobs’

Hopeful Californians are looking to the Pacific this winter for an end to California’s most punishing drought on record.

The reason: what appears to be a monster El Niño in the making. The abnormally warm waters along the equator could mean a wet winter.

There are no guarantees, but there have been portents. On one Saturday in July, San Diego got more rain than it got the entire month of January.

That same month, ESPN broadcaster Dan Shulman broke the news to baseball fans from underneath a golf umbrella: “For the first time in 20 years, a game has been postponed because of rain here in Anaheim.”

You can thank Dolores for that, a hurricane that managed to make it farther north than normal. The intense Pacific hurricane season bears the fingerprints of El Niño, which is already getting hyped as a potential drought-buster.

“Yes, and deservedly so,” says Kevin Trenberth, a Distinguished Senior Scientist at the National Center for Atmospheric Research in Boulder, Colorado.

“For this time of year, the El Niño is as strong as it’s ever been.”

Storms headed for the California coast run into the Ridiculously Resilient Ridge, represented by the “H” in this graphic. (David Pierce/ KQED) 

Strength in this case is measured by how much warmer surface temperatures are than normal, in the tropical Pacific. And this one looks to be about as strong as the legendary El Niño of 1997-98, which was the strongest on record, peaking at about 2.3 degrees Celsius above normal.

In the ocean, a spike of more than two degrees is like sticking a hot poker into the climate system. Pacific storms sucked up moisture from extremely warm equatorial waters and pretty much dumped it on California. San Francisco got double its normal rainfall that year.

Enter the Blob

But this time around, there are other things brewing in the Pacific: patches of freakishly warm water spread far and wide, up the California coast to the persistently warm vortex, hundreds of miles across, christened by climate scientists as “the Blob.”

“That is definitely the wildcard with this El Niño,” warns Bill Patzert, a climatologist at NASA’s Jet Propulsion Lab in Pasadena and an advisor to federal El Niño forecasters.

He says unlike in 1997, the Blob has been a fixture during the current drought. It’s essentially the sidekick of that “Ridiculously Resilient Ridge,” the stubborn bubble of high-pressure that’s been parked off the north coast for the past couple of years, diverting winter storms up and around California.

The “Blob” is associated with the persistent ridge of high pressure that has detoured the winter storm track around California. (NOAA)

“And so the question is, who wins in the battle of the Blob and the El Niño,” says Patzert, “and what impact that’ll have on rainfall on the West Coast of the U.S. this fall, into the winter.”

Patzert says if the Blob and its ridge dominate, we could wring less water out of this El Niño.

“What we’re having here is battling blobs!”

But not everyone’s on the edge of their seat.

“It doesn’t fit with my concept of how things work,” says Trenberth. On the contrary, he maintains, the presence of all this warm water — especially close to the coast — could mean heavier rains from the storms we do get.

A Mixed Blessing

“The potential in California for rains to be torrential this winter is quite high because of the warm water,” Trenberth says.

That’s because, as a general rule, the warmer the water, the more moisture gets picked up by the atmosphere and by any emerging storms.

Ocean waters near California have warmed further in recent weeks, and remain far above normal. (NOAA RTG)

“Those storms are apt to pick up moisture from any warm water that’s lying around all along the West Coast,” says Trenberth, “and it just feeds those storms.”

That would be both good and bad news. While the reservoirs refill, the rivers could easily overfill, causing flooding and landslides — much like in 1997-98. Trenberth will take that glass as half-full.

“The way things are shaping up it sure looks like an end to the drought to me,” he says, “depending on how you define the drought.”

Patzert agrees the current El Niño is looking like a monster — “Godzilla,” to use his favorite moniker. But he’s concerned the Blob and its ridge could become at least partial spoilers, blocking out storms from the northern Pacific, leaving the door open only for El Niño-driven storms from the tropics.

That could mean Southern California gets a soaking, but the northern part of the state — where most of the major reservoirs are — misses out.

“There is almost certainly going to be a dividing line,” says Stanford climate scientist Daniel Swain. “And it’s possible that dividing line could occur somewhere in Northern California.”

Patzert hopes that isn’t the case.

“If that happens, I’m definitely going to have to go into witness protection,” he frets, “because ‘my’ El Niño, the Great Wet Hope, will only deliver half the package.”

Whatever we get, it’s a package that won’t be delivered for at least three months, when California’s long-awaited “rainy” season is due.

Read/Listen to the original post: http://ww2.kqed.org/