Posts Tagged ‘El Niño’
Is La Nada adding to screwed-up US weather
Photo by Julie Denesha/Getty Images
Record snowfall, killer tornadoes, devastating floods: There’s no doubt about it. Since Dec. 2010, the weather in the USA has been positively wild. But why?
Some recent news reports have attributed the phenomenon to an extreme “La Niña,” a band of cold water stretching across the Pacific Ocean with global repercussions for climate and weather. But NASA climatologist Bill Patzert names a different suspect: “La Nada.”
“La Niña was strong in December,” he says. “But back in January it pulled a disappearing act and left us with nothing – La Nada – to constrain the jet stream. Like an unruly teenager, the jet stream took advantage of the newfound freedom–and the results were disastrous…”
“By mid-January 2011, La Niña weakened rapidly and by mid-February it was ‘adios La Niña,’ allowing the jet stream to meander wildly around the US. Consequently the weather pattern became dominated by strong outbreaks of frigid polar air, producing blizzards across the West, Upper Midwest, and northeast US.”
The situation lingered into spring — and things got ugly. Russell Schneider, Director of the NOAA-NWS Storm Prediction Center, explains:
“First, very strong winds out of the south carrying warm, moist air from the Gulf of Mexico met cold jet stream winds racing in from the west. Stacking these two air masses on top of each other created the degree of instability that fuels intense thunderstorms.”
Extreme contrasts in wind speeds and directions of the upper and lower atmosphere transformed ordinary thunderstorms into long-lived rotating supercells capable of producing violent tornadoes.2
In Patzert’s words, “The jet stream — on steroids — acted as an atmospheric mix master, causing tornadoes to explode across Dixie and Tornado Alleys, and even into Massachusetts…”
All this because of a flaky La Niña..?
And of course there’s this million dollar question: “Does any research point to climate change as a cause of this wild weather?”
“Global warming is certainly happening,” asserts Patzert, “but we can’t discount global warming or blame it for the 2011 tornado season. We just don’t know … Yet.”
Not that non-scientists won’t leap to negative conclusions as a result.
Not that anti-scientists won’t leap to stupid conclusions as a result.
Tree rings illustrate an 1,100-year history of El Niño and La Niña
El Niño and its partner La Niña, the warm and cold phases in the eastern half of the tropical Pacific, play havoc with climate worldwide. Predicting El Niño events more than several months ahead is now routine, but predicting how it will change in a warming world has been hampered by the short instrumental record. An international team of climate scientists has now shown that annually resolved tree-ring records from North America, particularly from the US Southwest, give a continuous representation of the intensity of El Niño events over the past 1100 years and can be used to improve El Niño prediction in climate models…
“Our work revealed that the towering trees on the mountain slopes of the US Southwest and the colorful corals in the tropical Pacific both listen to the music of El Niño, which shows its signature in their yearly growth rings,” explains Li. “The coral records, however, are brief, whereas the tree-ring records from North America supply us with a continuous El Niño record reaching back 1100 years.”
The tree rings reveal that the intensity of El Niño has been highly variable, with decades of strong El Niño events and decades of little activity. The weakest El Niño activity happened during the Medieval Climate Anomaly in the 11th century, whereas the strongest activity has been since the 18th century.
These different periods of El Niño activity are related to long-term changes in Pacific climate. Cores taken from lake sediments in the Galapagos Islands, northern Yucatan, and the Pacific Northwest reveal that the eastern-central tropical Pacific climate swings between warm and cool phases, each lasting from 50 to 90 years. During warm phases, El Niño and La Niña events were more intense than usual. During cool phases, they deviated little from the long-term average as, for instance, during the Medieval Climate Anomaly when the eastern tropical Pacific was cool.
“Since El Niño causes climate extremes around the world, it is important to know how it will change with global warming,” says co-author Shang-Ping Xie. “Current models diverge in their projections of its future behavior, with some showing an increase in amplitude, some no change, and some even a decrease. Our tree-ring data offer key observational benchmarks for evaluating and perfecting climate models and their predictions of the El Niño-Southern Oscillation under global warming.”
Often, I take these news items from Science Daily and construct a post directly from the source article. In this instance it would be from the University of Hawaii at Manoa. But, if you click the link you’ll see just to the right of the article at SD there are a number of archived articles on the same topic going back several years – which I believe many of you would find interesting.
While this article adds information to the pool of data there aren’t any particular conclusions about climate change drawn from the study. My first question, in fact, would be to ask if there is additional information about the Pacific Decadal Oscillation that can be acquired from this research. Over time, the PDO has assumed a strong role in the El Niño/La Niña meteorological patterns.
Last snow of the spring – we hope!
This is supposed to be the last snow storm of springtime.
El Niño has been good to Lot 4 and our high desert country. Precipitation has been well above normal, mostly powder snow. Base up at the Santa Fe ski area is 10 feet – before last night’s storm.
That moisture will perc down into the Ancha aquifer and do us all nothing but good.
Climate skeptics have their head in the sand
Climate skeptics who argue that global warming has stopped have their “heads in the sand”, according to the UK’s Met Office. A recent dip in global temperatures is down to natural changes in weather systems, a new analysis shows, and does not alter the long-term warming trend.
In a statement published on its website, it says: “Anyone who thinks global warming has stopped has their head in the sand. “The evidence is clear, the long-term trend in global temperatures is rising, and humans are largely responsible for this rise. Global warming does not mean that each year will be warmer than the last.”
The new research confirms that the world has cooled slightly since 2005, but says this is down to a weather phenomena called La Niña, when cold water rises to the surface of the Pacific Ocean. Despite this effect, the office says, 11 of the last 13 years are the warmest ever recorded…
The apparent cooling trend is exaggerated by a record high temperature in 1998 caused by a separate weather event, El Niño, she said. “You could look at what happened in 1998 and say that global warming accelerated and that’s not true either.
We have the same sort of poli-sci skeptics here in the States, of course. Ready and willing to reject the sum of peer-reviewed analysis on the basis of one or another hiccup paraded about like all the bought-and-paid-for rejections of cigarette smoking as being at all causative of human illness.
As much as conservatives and reactionaries bemoan what they call political correctness, they are the originators of that particular illness and have embraced it with all the fervor of whichever True Belief their leaders proffer. Lately, no human need bear any responsibility for climate change is the scripture.
Oh, and I wouldn’t have been so polite about where they’re hiding their heads.
