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New series of climate studies aim to pinpoint global warming impacts on key natural resources

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Glen Canyon Dam. Photo via U.S. Bureau of Reclamation.

Arizona researchers to focus on Colorado River flows as feds grant $7 million for 50-plus research projects

By Summit Voice

FRISCO — Arizona-based researchers will lead an effort to pinpoint how global warming will affect Colorado River flows in the coming decades, with an eye toward exploring links between Pacific Ocean climate patterns like El Niño/La Niña cycles and the occurrence of extreme wet or dry conditions.

The two-year study will result in a streamflow projection product that better accounts for physical mechanisms of weather and climate on a regional and local scale, that can be directly used by water resource providers.

The research project is one more than 50 studies funded by grants from the U.S. Department of Interior’s regional climate centers as part of President Obama’s Climate Action Plan to reduce carbon pollution, move the economy toward clean energy sources and begin to prepare communities for the impacts of climate change. Continue reading

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Climate: Is the Southwest ‘stuck’ in a drought pattern?

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NOAA’s winter outlook offers little relief for Arizona, New Mexico

By Bob Berwyn

FRISCO — Drought conditions may persist across the southwestern U.S. this winter and may redevelop across the Southeast, according to the seasonal outlook from NOAA’s Climate Prediction Center.

“Even though we don’t have La Niña, the atmosphere across the Pacific seems to be stuck in a La Niña mode … It’s been quite surprising to us, how persistent the pattern is,” said Mike Halpert, acting director of the Climate Prediction Center.

Parts of the Southwest, especially New Mexico, have been experiencing one of the driest periods on record, and Halpert said there is “decent agreement” in the CPC’s models on the climate signal that has resulted in the persistent trend. Continue reading

How will global warming affect El Niño?

Study shows how external influences shape Pacific weather patterns

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New research may help show how global warming will affect El Niño.

By Summit Voice

FRISCO — By studying coral samples from a remote Pacific atoll, Australian researchers say they’ve found evidence that external influences can change the intensity of the periodic El Niño cycle. By extension, they said, human-caused global warming could also alter the pattern, though the observational record is too short to determine whether that’s already happening.

The research was led by scientist with the ARC Centre of Excellence for Climate System Science and  published in Nature Geoscience.

“Our research has showed that, while the development of La Niña and El Niño events is chaotic and hard to predict, the strength of these events can change over long time spans due to changes in the global climate,” said one of the paper’s authors, Australian climate researcher Dr. Steven Phipps. Continue reading

Climate: With no Niño — what’s a forecaster to do?

Fall and winter outlook still murky

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Seasonal weather forecasters look out to sea surface temperatures in the equatorial Pacific to get an idea of what weather patterns may bring.

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Without a stron El Niño or La Niña in the outlook, forecasters are not confident of projecting pronounced temperature or precipitation anomalies.

By Bob Berwyn

FRISCO — With no strong El Niño or La Niña on the horizon, forecasters are struggling even more than usual to develop seasonal outlooks for the western U.S. The periodic El Niño-La Niña cycle is a large-scale shift in the Pacific involving a complex interplay of winds, ocean currents and sea surface temperatures.

In the U.S. the warm El Niño phase is associated with wetter than average conditions in the Desert Southwest and California, and can result in below average precipitation in the Pacific Northwest.

La Niña, on the other hand, has been linked with Southwestern drought conditions and heavy precipitation in the Pacific Northwest. That persistent moist flow off the northwestern Pacific can also favor parts of Colorado with good winter snows, but the ENSO climate signal is more marginal in Colorado than in other areas. Continue reading

Climate: Better El Niño forecasting ahead?

Early warning could help regional preparedness efforts

A new climate model could help project El Niño conditions a year in advance.

A new climate model could help project El Niño conditions a year in advance.

By Summit Voice

FRISCO — Forecasting the emergence of El Niño well in advance has long been a goal of climate scientists and a team of German researchers say they may have devised a model that extends the lead time to a year.

Published recently in the Proceedings of the National Academy of Sciences, their paper describes how the model uses high-quality data of air temperatures as the basis for making long-term projections about El Niño, a warm phase of a periodic Pacific Ocean cycle that affects climate and weather around the world.

“Enhancing the preparedness of people in the affected regions by providing more early-warning time is key to avoiding some of the worst effects of El Niño,” said Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research, who co-authored the paper with Josef Ludescher, of Justus-Liebig Universität Giessen. Continue reading

Global warming may drive more active La Niña pattern

Broad tree-ring record provides accurate ENSO history

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Researchers say tree ring records show that El Niño activity during the 20th century has largely been outside the range of natural variability.

By Summit Voice

Climate scientists have long suspected that global warming has an influence on the Pacific Ocean El Niño- La Niña cycle (El Niño-Southern Oscillation), but instrumental records tracking the shift between above- and below average sea surface temperatures don’t go back far enough to provide context for any recent changes in the pattern.

But scientists working at the International Pacific Research Center, University of Hawaii at Manoa say a new tree ring record extending back about 700 years has helped decipher long-term trends. The tree ring samples from both the tropics and mid-latitudes in both hemispheres support the idea that the unusually high ENSO activity in the late 20th century is a footprint of global warming said Jinbao Li, lead author of the study published online in the journal Nature Climate Change. Continue reading

Climate: Drought conditions edge westward

Wet, cool spring brings relief to Midwest

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The most severe areas of drought encompass parts of the central-southern plains, spreading southwest into parts of Colorado and New Mexico.

By Bob Berwyn

FRISCO — Drought woes have eased in the Midwest after a wet spring, but the far West,  California in particular, are facing continued dry conditions. California has reported its driest year to-date on record, with only 27 percent of normal precipitation for January through April. That doesn’t bode well for the state’s water supplies, although at least reservoir storage is close to normal in California.

New Mexico and Nevada are in bad shape when it comes to reservoir storage and there’s little relief in sight at the end of the snow season. Forecasters with the National Oceanic and Atmospheric Administration said dry soil conditions in the southwest could contribute to higher than average temperatures this summer. Continue reading

Colorado: No El Niño, no La Niña – what’s driving the weather?

Spring outlook trends toward warm and dry conditions

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The Madden-Julian Oscillation has played a role in Colorado weather this winter.

By Summit Voice

FRISCO — With neither El Niño or a La Niña conditions in the Pacific Ocean, long-range weather forecasters have been struggling to develop confidence in their outlook for the coming spring season — a critical time for much of the West in terms of getting some relief from drought conditions.

A wet and cool spring could at least take the edge off the drought in some areas, helping to maintain stream flows and reduce the potential for massive and dangerous wildfires. Conversely, a return to last year’s very dry and warm spring pattern would spell trouble for places like Colorado.

So if the El Niño-La Niña cycle isn’t driving the weather, what is? What we do know is that conditions over the Pacific Ocean are the key to understanding exactly what path storms will take across the western United States, and that conditions in the North Atlantic can also be a factor. Continue reading

New coral data traces 7,000 years of El Niño history

20th century oscillations show intensification that may be linked with global warming

El Nino graphic

A NOAA graphic showing early January 2012 ocean surface temperature anomalies.

By Summit Voice

SUMMIT COUNTY — Atmospheric scientists say they’ve used coral records to trace the history of El Niño cycles going back about 7.000 years, showing that 20th century oscillations  are much stronger than those captured in the fossil record.

But the study also showed large natural variations in past ENSO strength, making it difficult to attribute the 20th century intensification of ENSO to rising carbon dioxide levels. Such large natural fluctuations in ENSO activity are also apparent in multi-century climate model simulations, but the 20th century intensification stands out as statistically significant and could be linked with global warming.

The new information will help assess the accuracy of climate model projections for 21st century climate change in the tropical Pacific. Continue reading

Climate: NOAA drops El Niño watch

Forecasters call for neutral conditions, but say a La Niña is not out of the question

n El Niño never managed to establish itself in the equatorial Pacific this year.

The three-month precipitation outlook from NOAA’s Climate Prediction Center.

By Summit Voice

FRISCO — With sea surface temps cooling to near average in much of the equatorial Pacific, NOAA’s Climate Prediction Center has dropped an El Niño watch that’s been in effect for the past several months.

El Niño is part of a cyclical pattern of sea surface temperature variations that affects global weather patterns. The emerging El Niño forecast last spring and summer offered some hope for drought relief in the parched Southwest and the southern tier of states, where warmer than average Pacific Ocean temps can help boost winter and spring precipitation.

During La Niña years, when cooler-than-average sea surface temperatures prevail in the same region, the storm track often shifts northward, driving storms into the Pacific Northwest and then down across the northern Rockies and northwest Colorado. Continue reading

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