Posted on February 28, 2014 by Bob Berwyn
What’s the role of coniferous trees in regulating climate?
Fast growth of particles from pine tree fumes surprises researchers
By Summit Voice
FRISCO — Forests may play a much bigger role in global climate than previously believed. In addition to cycling carbon, it appears that gases wafting from conifers quickly form small particles that can reflect sunlight and promote cloud formation, according to a new study that looked at forest aerosols at the molecular level.
“In many forested regions, you can go and observe particles apparently form from thin air. They’re not emitted from anything, they just appear,” said Joel Thornton, a University of Washington associate professor of atmospheric sciences. Continue reading
Filed under: climate and weather, Environment, forests | Tagged: aerosols, atmospheric science, climate, forests, global warming | 1 Comment »
Posted on November 27, 2013 by Bob Berwyn
Air pollution can be a big factor in development of thunderclouds
Air pollution can have a significant impact on the development of thunderclouds, causing cloud remnants to persist longer. bberwyn photo.
FRISCO — Air pollution can have a significant effect on the development of thunderhead clouds, causing the cloud remnants to persist high in the atmosphere long after thunderstorms dissipate. This, in turn, can affect daily temperature ranges, as the lingering clouds partially cool the Earth during the day with their shadows, but trap heat to keep nighttime temperatures warmer.
The new study, from the Department of Energy’s Pacific Northwest National Laboratory, helps answer long-running questions about how airborne pollutants affect climate warming. The findings will help provide a gauge for the accuracy of weather and climate models.
“This study reconciles what we see in real life to what computer models show us,” said atmospheric scientist Jiwen Fan. “Observations consistently show taller and bigger anvil-shaped clouds in storm systems with pollution, but the models don’t always show stronger convection. Now we know why.” Continue reading
Filed under: climate and weather, Environment | Tagged: aerosols, air pollution, atmospheric science, cloud formation, Environment | 1 Comment »
Posted on November 7, 2013 by Bob Berwyn
New study suggests natural aerosols may be a bigger factor than previously thought
By Summit Voice
FRISCO — In their quest to better understand the role of aerosols in the Earth’s climate, researchers may have to try and find the cleanest parts of the atmosphere.
Knowing to what degree both human-caused and natural aerosols mask the effects of heat-trapping greenhouse gases is crucial to making accurate climate predictions, according to a new study that assessed 28 factors that could affect the uncertainties in cloud brightness.
Natural aerosols, such as emissions from volcanoes or plants, may contribute more uncertainty than previously thought to estimates of how the climate might respond to greenhouse gas emissions. Continue reading
Filed under: climate and weather, Environment, global warming | Tagged: aerosols, atmospheric science, climate change, global warming, Greenhouse gas | Leave a comment »
Posted on March 3, 2013 by Bob Berwyn
Next step: Figure out how climate change may affect those patterns
Clouds of dust swirling around the world may have significant impact
By Summit Voice
SUMMIT COUNTY — Airborne dust has been shown to speed up snowmelt in the Colorado Rockies, but there’s more to to global dust and snow story, according to a NOAA-led study showing that dust and microorganisms from as far away as the Sahara help spur the precipitation that California counts on for its water supply.
The CalWater field campaign, funded by the California Energy Commission and led by NOAA and the University of California San Diego, could help western states better understand the future of their water supply and hydropower generation as climate change influences how much and how often dust travels around the world and alters precipitation far from its point of origin. Continue reading
Filed under: climate and weather, Snow and weather | Tagged: Asian Dust, atmospheric science, climate, National Oceanic and Atmospheric Administration, Sahara, Sierra Nevada snow, University of California San Diego | 2 Comments »
Posted on February 26, 2013 by Bob Berwyn
Observational data confirms pattern changes
Heat building up over the Arctic is interfering with global circulation patterns, leading to more intense, frequent and extended extreme weather events. Diagram courtesy NOAA.
By Summit Voice
FRISCO — Increasing global temperatures are “freezing” atmospheric waves, resulting in more frequent weather extremes, including the 2011 U.S. heat wave and a 2010 heat wave in Russia that coincided with unprecedented flooding in Pakistan.
Scientists have surprised by how far outside past experience some of the recent extremes have been. The new data show that the emergence of extraordinary weather is not just a linear response to the mean warming trend.
“What we found is that during several recent extreme weather events these planetary waves almost freeze in their tracks for weeks,” said Vladimir Petoukhov, lead author of a study to be published this week in the US Proceedings of the National Academy of Sciences. “So instead of bringing in cool air after having brought warm air in before, the heat just stays. In fact, we observe a strong amplification of the usually weak, slowly moving component of these waves,” Petoukhov said. Continue reading
Filed under: Arctic, climate and weather, Environment, global warming | Tagged: atmospheric science, climate change, extreme weather, Jet stream | 1 Comment »
Posted on September 18, 2012 by Bob Berwyn
Researchers estimate 10 percent increase in rainfall during extreme events for every 1-degree Celsius of warming
Rainfall amounts during extreme weather events in the tropics are expected to increase by 10 percent for every 1-degree Celsius rise in temperatures. Photo by Bob Berwyn.
By Summit Voice
SUMMIT COUNTY — Researchers at MIT say extreme rainfall in the Earth’s tropical regions appear to be more sensitive to global warming than other parts of the world. While they don’t fully understand the mechanism for that higher sensitivity, they estimate that rainfall amounts during extreme weather events — monsoons, thunderstorms and tropical cyclones — are likely to increase by 10 percent for every 1-degree Celsius increase in temperatures.
“The study includes some populous countries that are vulnerable to climate change … and impacts of changes in rainfall could be important there,” said Paul O’Gorman, assistant professor of Atmospheric Science at MIT.
In general, most climate models agree that a warming atmosphere hold more water vapor. When storm systems develop, the increased humidity prompts heavier rain events that become more extreme as the climate warms. Continue reading
Filed under: climate and weather, Environment, global warming, tropical storms and hurricanes | Tagged: atmospheric science, climate change, El Nino, extreme rainfall events, extreme weather, global warming, Nature Geoscience, tropics | Leave a comment »
Posted on August 26, 2012 by Bob Berwyn
Researchers propose cloud-brightening to avert strong storms
A composite NOAA image of Hurricane Andrew, in 1992.
By Summit Voice
SUMMIT COUNTY — While hurricanes are often feared as a destructive force of nature, they are also one of nature’s great climate regulators, helping to disperse ocean and atmospheric heat away from the equatorial region.
But some environmental scientists think it might be a good idea to reduce the intensity of hurricanes by seeding clouds to decrease sea surface temperatures when hurricanes form. Theoretically, the scientists claim the technique could reduce hurricane intensity by a category.
The team focused on the relationship between sea surface temperature and the energy associated with the destructive potential of hurricanes. Rather than seeding storm clouds or hurricanes directly, the idea is to target marine stratocumulus clouds, which cover an estimated quarter of the world’s oceans, to prevent hurricanes forming.
“Hurricanes derive their energy from the heat contained in the surface waters of the ocean,” said Dr Alan Gadian from the University of Leeds. “If we are able to increase the amount of sunlight reflected by clouds above the hurricane development region then there will be less energy to feed the hurricanes.” Continue reading
Filed under: climate and weather, Environment, tropical storms and hurricanes | Tagged: atmospheric science, cloud brightening, Cloud reflectivity modification, cloud seeding, hurricanes, Sea surface temperature, University of Leeds | 1 Comment »