Posted on July 15, 2013 by Bob Berwyn
Early warning could help regional preparedness efforts
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. (more…)
Filed under: climate and weather, El Niño, La Niña | Tagged: climate, climate projections, El Nino, ENSO, Hans Joachim Schellnhuber, Potsdam Institute for Climate Impact Research | Leave a Comment »
Posted on July 1, 2013 by Bob Berwyn
Broad tree-ring record provides accurate ENSO history
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. (more…)
Filed under: climate and weather, El Niño, global warming, La Niña | Tagged: climate, El Niño-Southern Oscillation, El Nino, ENSO, global warming, tree ring record, University of Hawaiʻi at Mānoa | 6 Comments »
Posted on May 23, 2013 by Bob Berwyn
Sparse January snow across the Colorado Plateau in January 2013. Bob Berwyn photo.
Drop linked primarily with warmer spring temperatures
By Summit Voice
SUMMIT COUNTY — Long-time skiers often say that skiing was better in the good old days, and new research from the U.S. Geological Survey suggests that those claims are based on more than nostalgia — notwithstanding the occasional bumper crop of powder like in 2010-2011.
After taking an in-depth look at snowfall and temperature records, federal scientists said warmer spring temperatures since the 1980s have caused an estimated 20 percent loss of snow cover across the Rocky Mountains of western North America — especially at lower elevations where temperatures have the greatest effect. (more…)
Filed under: climate and weather, Colorado, El Niño, Environment, global warming, La Niña, seasons, Snow and weather, water | Tagged: Geophysical Research Letters, United States Geological Survey | 1 Comment »
Posted on April 17, 2013 by Bob Berwyn
Ice cores suggest current climate is in the natural range of variability
Climate scientists track Antarctic changes, Bob Berwyn photo.
By Summit Voice
FRISCO — Ice cores from West Antarctica spanning the last 2,000 years suggest that recent warming and glacier loss in the region is comparable to other warm periods during that span.
Most of the recent warming may be related to powerful El Niño phases in the tropical Pacific in the 1990s, said University of Washington researcher Eric Steig. The ice core record shows similar temperature spikes in the 1830s and 1940s, he said, adding that the recent warming cannot be attributed with confidence to human-caused global warming.
Steig built on previous research showing that rapid thinning of Antarctic glaciers was accompanied by rapid warming and changes in atmospheric circulation near the coast. The new study suggests that the 1990s were not all that different from some of those earlier warm spells. (more…)
Filed under: Antarctica, climate and weather, El Niño, Environment, global warming | Tagged: Antarctica, climate change, global warming, West Antarctic Ice Sheet | Leave a Comment »
Posted on April 12, 2013 by Bob Berwyn
Natural climate variability the biggest player, scientists say
Drought conditions persist across the central part of the country.
By Bob Berwyn
SUMMIT COUNTY — Last summer’s crippling Great Plains drought can’t definitively be linked with global warming, according to a team of federal scientists from various agencies. In a new report issued this week, the researchers said the drought was probably caused by a confluence of natural climate variations that might only come together in a similar constellation once a century.
Cyclical variations in ocean temperatures — especially the combination of a cooler-than-average Pacific Ocean and a warm phase of the North Atlantic Multidecadal Oscillation may have nudged the region toward drought conditions, but those factors tend to be more of a factor in suppressing winter precipitation. (more…)
Filed under: climate and weather, Drought, El Niño, global warming, La Niña, Uncategorized | Tagged: 2012 drought, Dust Bowl, El Nino, global warming, Great Plains, La Niña, National Oceanic and Atmospheric Administration | 2 Comments »
Posted on March 22, 2013 by Bob Berwyn
Natural climate variables so far outweigh global warming impacts
The North American monsoon is an important climate factor in the Rocky Mountains.
By Summit Voice
SUMMIT COUNTY — The timing and amount of monsoon rains in the northern hemisphere have important economic and environmental ramifications, for example for farmers in Asia and the wildfire season in the southwestern U.S.
As a result, climate researchers have been trying to determine how the Earth’s steady warming will affect those seasonal rainfall patterns, and so far, the jury is still out. Some recent research has suggested that the timing of the North American monsoon might be delayed, while other studies have indicated that there could be an overall increase in monsoon precipitation.
In one of the latest studies, scientists with the International Pacific Research Center, University of Hawaii at Manoa, say that monsoon rainfall patterns appear to more influenced by natural long-term swings in ocean surface temperatures. The Interdecadal Pacific Oscillation or mega-El Niño-Southern Oscillation, which has lately been in a mega-La Niña or cool phase is one key factor, and shifts in the Atlantic Multidecadal Oscillation, also contributes to the intensification of monsoon rainfall. (more…)
Filed under: climate and weather, El Niño, global warming, La Niña | Tagged: Atlantic Multidecadal Oscillation, climate, global warming, monsoon, north american monsoon, Pacific Decadal Oscillation | 2 Comments »
Posted on March 18, 2013 by Bob Berwyn
Spring outlook trends toward warm and dry conditions
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. (more…)
Filed under: climate and weather, Colorado, Drought, El Niño, La Niña, Summit County Colorado, Weatherblog | Tagged: Colorado weather, drought, El Nino, ENSO, La Niña, Madden-Julian Oscillation | 1 Comment »
Posted on March 2, 2013 by Bob Berwyn
Australia, parts of Africa and South America report record-high readings
Six of the hottest ten summers on record have occurred this century, and only two occurred before 1990.
By Summit Voice
FRISCO — At the start of meteorological autumn for the southern hemisphere, The Australian Bureau of Meteorology reports that the country recorded its hottest-ever summer season, breaking the 1997-1998 mark by 0.1 degrees Celsius.
The most extreme heat was in the beginning of January, when a heat wave settled across much of Australia, including Tasmania, leading to wildfires and record-high readings in parts of the country, with temperatures soaring as high as 49.6 degrees Celsius (121 degrees fahrenheit). (more…)
Filed under: climate and weather, El Niño, Environment, global warming, seasons | Tagged: Australia, climate, global warming, southern | 3 Comments »
Posted on February 9, 2013 by Bob Berwyn
Findings could help improve long-range winter forecasts
Shifting cycles of warmer and cooler water in the central Pacific influence weather patterns around the world.
By Summit Voice
FRISCO — A new study that sorts El Niño events into two categories could help forecasters develop better long-range forecasts to predict how the periodic warming of equatorial East Pacific waters may affect winter weather.
Part of the data for the research came from an array of buoys across the Pacific called the TAO-Triton array. The buoys observes conditions in the upper ocean to forecast El Niño months in advance, and for monitoring it as it grows and decays.
After analyzing all El Niño events since 1979, the NOAA and University of Washington scientists said the El Niños that show a drop in outgoing long-wave radiation from the tops of deep convective clouds are the ones that tend to play havoc with winter weathers. (more…)
Filed under: climate and weather, Drought, El Niño, seasons | Tagged: El Niño-Southern Oscillation, El Nino, National Oceanic Atmospheric Administration, University of Washington, winter weather ENSO | 5 Comments »
Posted on January 19, 2013 by Bob Berwyn
Study may unlocks new climate clues
Wet conditions in coastal East Africa are associated with cool sea surface temperatures in the eastern Indian Ocean and warm sea surface temperatures in the western Indian Ocean, which cause ascending atmospheric circulation over East Africa and enhanced rainfall. (Courtesy Jessica Tierney, et al, 2013)
By Summit Voice
FRISCO — A new study may help forecast drought conditions in the oft famine-stricken and geopolitically crucial Horn of Africa. More than 40 million people in the region often live in exceptional drought conditions, most recently in 2010-2011, when the worst drought in decades triggered a humanitarian crisis.
It’s long been clear that El Niño can affect precipitation in the region, very little is known about the drivers of long-term shifts in rainfall. But the study suggests that temperatures in the Indian Ocean may be the key to understanding precipitation patterns in East Africa.
“The problem is, instrumental records of temperature and rainfall, especially in East Africa, don’t go far enough in time to study climate variability over decades or more, since they are generally limited to the 20th century,” said Woods Hole Oceanographic Institution geologist Jessica Tierney, lead author of the paper published in the journal Nature. (more…)
Filed under: climate and weather, Drought, El Niño, global warming, La Niña | Tagged: climate, drought, Horn of Africa, Indian Ocean | 1 Comment »