Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

California 2100: More frequent and more severe droughts and floods likely

22.10.2015

El Nino and global warming work together to bring more extreme weather

In the future, the Pacific Ocean's temperature cycles could disrupt more than just December fishing. A study published in Nature Communications suggests that the weather patterns known as El Nino and La Nina could lead to at least a doubling of extreme droughts and floods in California later this century.


On the left, La Nina cools off the ocean surface (greens and blues) in the winter of 1988. On the right, El Nino warms up it up (oranges and reds) in the winter of 1997.

Credit: Jin-Ho Yoon/PNNL

The study shows more frequent extreme events are likely to occur. Other research shows the Golden State's average precipitation increasing gradually, but not enough to account for the occurrence of extreme events. A better understanding of what gives rise to El Nino and La Nina cycles -- together known as El Nino-Southern Oscillation -- might help California predict and prepare for more frequent droughts and floods in the coming century.

"Wet and dry years in California are linked to El Nino and La Nina. That relationship is getting stronger," said atmospheric scientist Jin-Ho Yoon of the Department of Energy's Pacific Northwest National Laboratory. "Our study shows that ENSO will be exhibiting increasing control over California weather."

Rain's range

California is experiencing one of the most severe droughts in its history, but it's not clear if a warmer world will make droughts worse, more frequent or perhaps even improve the situation. After all, warmer air can hold more water, and some research suggests global warming could increase California's average rain and snowfall.

However, research also suggests future rain will come down more as light drizzles and heavy deluges and less as moderate rainfall. Yoon and colleagues from PNNL and Utah State University in Logan, Utah, wondered if droughts might follow a similar pattern.

To find out, the researchers looked at what happens to California in global climate models. They simulated two periods of time: 1920 to 2005 using historical measurements; and 2006 to 2080 using conditions in which very few efforts are made to reduce greenhouse gas emissions. They chose this future scenario to examine the most extreme case.

To understand how well the simulations worked, they used two tactics to show reproducibility: In one tactic, they used a compilation of 38 different models. In the other, they re-ran a single model 30 times. The more similar the results, the more sure the researchers were of the finding.

Weather pendulum

The models showed that in the future, assuming emissions continue to increase, California seasons will exhibit more excessively wet and excessively dry events. These results suggest that the frequency of droughts could double and floods could triple between the early 20th century and late 21st century.

"By 2100, we see more -- and more extreme -- events. Flooding and droughts will be more severe than they are currently," said Yoon.

But why? Yoon suspected the El Nino-Southern Oscillation. Every two to seven years, El Nino comes in and warms up the tropical Pacific Ocean a few degrees, increasing winter rain and snowpack in California. On a similar schedule, La Nina cools things off. Both disrupt regular weather in many regions around the globe.

To explore El Nino's connection to California precipitation, Yoon and colleagues ran a climate model with and without El Nino. In both simulations, they ramped up the concentration of carbon dioxide by 1 percent every year for 150 years. In just one of the runs, they removed El Nino's cyclical contribution by programming the sea surface temperatures to reflect only steady warming.

Without El Nino and La Nina, the frequency of extreme precipitation in California stayed constant for the simulation's century and a half. With ENSO, simulated California experienced wide swings in rainfall by the end of the period.

The results suggest that even though researchers expect rain and snowfall to increase as the climate warms, the manner in which the water hits California could be highly variable.

The El Nino-Southern Oscillation is still a bit of a mystery, said Yoon. Scientists only know El Nino and La Nina years, named for the Spanish terms for boy and girl, are coming by sea surface temperatures and other weather hints. Studies that investigate what controls the unruly children could help scientists predict unruly weather in the future.

###

This work was supported by the Department of Energy Office of Science.

Reference: Jin-Ho Yoon, S.-Y. Simon Wang, Robert R. Gillies, Ben Kravitz, Lawrence Hipps, and Philip J. Rasch. Increasing water cycle extremes in California and relation to ENSO cycle under global warming, Nature Communications, Oct. 21, 2015, DOI: 10.1038/ncomms9657.

Interdisciplinary teams at Pacific Northwest National Laboratory address many of America's most pressing issues in energy, the environment and national security through advances in basic and applied science. Founded in 1965, PNNL employs 4,400 staff and has an annual budget of nearly $1 billion. It is managed by Battelle for the U.S. Department of Energy's Office of Science. As the single largest supporter of basic research in the physical sciences in the United States, the Office of Science is working to address some of the most pressing challenges of our time. For more information on PNNL, visit the PNNL News Center, or follow PNNL on Facebook, Google+, LinkedIn and Twitter.

Media Contact

Mary Beckman
mary.beckman@pnnl.gov
509-375-3688

 @PNNLab

http://www.pnnl.gov/news 

Mary Beckman | EurekAlert!

Further reports about: floods global warming sea surface sea surface temperatures

More articles from Earth Sciences:

nachricht Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>