Study: Jet stream induced weather will remain normal and predictable – despite 'climate change'

Weather should remain predictable despite climate change

Simulations of jet stream behavior in a warming climate suggest ranges of forecasts in the mid-century will be similar to those in present day, MU study finds

COLUMBIA, Mo. – According to the Intergovernmental Panel on Climate Change, temperatures are expected to rise between 2.5 and 10 degrees Fahrenheit over the next century. This warming is expected to contribute to rising sea levels and the melting of glaciers and permafrost, as well as other climate-related effects. Now, research from the University of Missouri suggests that even as rising carbon dioxide levels in the atmosphere drive the climate toward warmer temperatures, the weather will remain predictable.

“The jet stream changes character every 10 to 12 days, and we use this pattern to predict the weather,” said Anthony Lupo, professor of atmospheric science in MU’s School of Natural Resources, which is located in the College of Agriculture, Food and Natural Resources. “We were curious about how this would change in a world with higher carbon dioxide levels. We found that in that warmer world, the variability of the jet stream remained the same.”

Lupo and Andrew Jensen, who earned his doctorate at MU, used an existing climate model to simulate jet stream flow in the Northern Hemisphere. The simulation monitored a variable that responds to jet stream flow changes and can indicate global-scale weather instability. Researchers used this variable to determine when the jet stream altered its flow. Since meteorologists can only accurately predict weather within the 10 to 12 days between jet stream flow changes, a shift in this time frame would directly impact weather predictability.

Over the course of a simulated 31 years, their observations indicated the jet stream would change its character about 30 to 35 times per year, a number that is consistent with current jet stream patterns. As the time frame used to predict weather did not change, the researchers concluded that weather would likely remain as predictable in a warmer world as it is today. The results do not address the effects of climate change on the nature or frequency of weather events but instead focus on the range of predictability afforded by the jet stream. In addition, the researchers did not extend the simulation past the mid-century to ensure their data was as accurate as possible.

“Climate change will continue to create a lot of ripple effects, but this experiment provides evidence that the range of forecasting will remain the same,” Lupo said.

https://vimeo.com/256484553

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The study, “The Dynamic Character of Northern Hemisphere Flow Regimes in a Near-Term Climate Change Projection,” was published in Atmosphere.

http://www.mdpi.com/2073-4433/9/1/27/htm (open access)

Abstract

The dynamic character of an enstrophy-based diagnostic, previously used in the study of atmospheric blocking, is examined here, in near-term future simulations from the Institut Pierre Simon Laplace Climate Model version 4 (IPSL-CM4) and version 5 (IPSL-CM5) climate models of the Northern Hemisphere flow for moderate climate change scenarios. Previous research has shown that integrated regional enstrophy (IE) increases during blocking onset and decay, which is a reflection of planetary-scale instability. In addition, IE has been shown previously to increase during flow regime transitions in general, even those not associated with blocking events. Here, a 31-year IE diagnostic time series is examined for changes in short term (5–40 days) planetary-scale variability that may correspond flow regime changes in an increased carbon dioxide environment. The time-series analysis herein indicates that the IE diagnostic provides evidence for approximately 30–35 atmospheric flow regime transitions per year in a warmer climate, which is similar to that of the control run and the latest 30-year observed climate, as derived from re-analyses. This result has implications regarding the predictability of weather in a warmer world.

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Gerry, England
February 24, 2018 2:24 am

In the real world that these types don’t seem to inhabit, the jetstream has already changed from zonal to meridional over the last few years leading to wild meanders north and south.
I believe the march of computer models has made forecasting worse by removing the human experience from the forecasts. The changed jetstream only makes that worse since it was admitted live on air during a BBC weather forecast that their models don’t work with a meridional jetstream.

February 24, 2018 10:42 am

You know they DID run their models out to 2100. A unavoidable need to satisfy their professional, if not ideoligical, curiosity.
The lack of comment on the results of the longer run suggests two reasons, both negative from the CAGW perspective:
1. No changes resulted. Therefore, high CO2 doesn’t materially change atmospheric conditions. Stability in one major area suggests stability in others.
2. Bizarre changes resulted. Changes that are simply not believable with long term evidence. Therefore, there are serious errors in the models which build on themselves and become obvious over the 50+ year period. Shorter term periods have a built-in, progressive but unknown failure to respect reality. More uncertainty than they wish admitted.
Non-responses are also responses.