PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

When it rains, it pours

Study estimates rate of intensification of extreme tropical rainfall with global warming

2012-09-17
(Press-News.org) CAMBRIDGE, Mass. — Extreme precipitation in the tropics comes in many forms: thunderstorm complexes, flood-inducing monsoons and wide-sweeping cyclones like the recent Hurricane Isaac.

Global warming is expected to intensify extreme precipitation, but the rate at which it does so in the tropics has remained unclear. Now an MIT study has given an estimate based on model simulations and observations: With every 1 degree Celsius rise in temperature, the study finds, tropical regions will see 10 percent heavier rainfall extremes, with possible impacts for flooding in populous regions.

"The study includes some populous countries that are vulnerable to climate change," says Paul O'Gorman, the Victor P. Starr Career Development Assistant Professor of Atmospheric Science at MIT, "and impacts of changes in rainfall could be important there."

O'Gorman found that, compared to other regions of the world, extreme rainfall in the tropics responds differently to climate change. "It seems rainfall extremes in tropical regions are more sensitive to global warming," O'Gorman says. "We have yet to understand the mechanism for this higher sensitivity."

Results from the study are published online this week in the journal Nature Geoscience.

A warm rain will fall

Global warming's effect on rainfall in general is relatively well-understood: As carbon dioxide and other greenhouse gases enter the atmosphere, they increase the temperature, which in turn leads to increases in the amount of water vapor in the atmosphere. When storm systems develop, the increased humidity prompts heavier rain events that become more extreme as the climate warms.

Scientists have been developing models and simulations of Earth's climate that can be used to help understand the impact of global warming on extreme rainfall around the world. For the most part, O'Gorman says, existing models do a decent job of simulating rainfall outside the tropics — for instance, in mid-latitude regions such as the United States and Europe. In those regions, the models agree on the rate at which heavy rains intensify with global warming.

However, when it comes to precipitation in the tropics, these models, O'Gorman says, are not in agreement with one another. The reason may come down to resolution: Climate models simulate weather systems by dividing the globe into a grid, with each square on the grid representing a wide swath of ocean or land. Large weather systems that span multiple squares, such as those that occur in the United States and Europe in winter, are relatively easy to simulate. In contrast, smaller, more isolated storms that occur in the tropics may be trickier to track.

An intensity of extremes

To better understand global warming's effect on tropical precipitation, O'Gorman studied satellite observations of extreme rainfall between the latitudes of 30 degrees north and 30 degrees south — just above and below the Equator. The observations spanned the last 20 years, the extent of the satellite record. He then compared the observations to results from 18 different climate models over a similar 20-year period.

"That's not long enough to get a trend in extreme rainfall, but there are variations from year to year," O'Gorman says. "Some years are warmer than others, and it's known to rain more overall in those years."

This year-to-year variability is mostly due to El Niño — a tropical weather phenomenon that warms the surface of the Eastern Pacific Ocean. El Niño causes localized warming and changes in rainfall patterns and occurs independent of global warming.

Looking through the climate models, which can simulate the effects of both El Niño and global warming, O'Gorman found a pattern. Models that showed a strong response in rainfall to El Niño also responded strongly to global warming, and vice versa. The results, he says, suggest a link between the response of tropical extreme rainfall to year-to-year temperature changes and longer-term climate change.

O'Gorman then looked at satellite observations to see what rainfall actually occurred as a result of El Niño in the past 20 years, and found that the observations were consistent with the models in that the most extreme rainfall events occurred in warmer periods. Using the observations to constrain the model results, he determined that with every 1 degree Celsius rise under global warming, the most extreme tropical rainfall would become 10 percent more intense — a more sensitive response than is expected for nontropical parts of the world.

"Unfortunately, the results of the study suggest a relatively high sensitivity of tropical extreme rainfall to global warming," O'Gorman says. "But they also provide an estimate of what that sensitivity is, which should be of practical value for planning."

### END


ELSE PRESS RELEASES FROM THIS DATE:

Majority of US Schools not ready for next pandemic, SLU researchers say

Majority of US Schools not ready for next pandemic, SLU researchers say
2012-09-17
ST. LOUIS – Many U.S. schools are not prepared for bioterrorism attacks, outbreaks of emerging infectious diseases or pandemics, despite the recent 2009 H1N1 influenza pandemic that resulted in more than 18,000 deaths worldwide, Saint Louis University researchers say. The study, led by Terri Rebmann, Ph.D., associate professor at SLU's Institute for Biosecurity, surveyed about 2000 nurses working in elementary, middle and high schools across 26 states. The findings reveal that only 48 percent of schools address pandemic preparedness and only 40 percent of schools have ...

AGU journal highlights – 17 September 2012

2012-09-17
The following highlights summarize research papers that have been recently published in Geophysical Research Letters (GRL), Journal of Geophysical Research – Solid Earth (JGR-B), Journal of Geophysical Research – Planets (JGR-E), Journal of Geophysical Research – Earth Surface (JGR-F), Journal of Geophysical Research – Biogeosciences (JGR-G). In this release: 1. Characterizing the surface composition of Mercury 2. African dust forms red soils in Bermuda 3. Sea level controls carbon accumulation in the Everglades 4. Climate change threatens permafrost in soil 5. ...

Dry-run experiments verify key aspect of Sandia nuclear fusion concept

Dry-run experiments verify key aspect of Sandia nuclear fusion concept
2012-09-17
ALBUQUERQUE, N.M. — Magnetically imploded tubes called liners, intended to help produce controlled nuclear fusion at scientific "break-even" energies or better within the next few years, have functioned successfully in preliminary tests, according to a Sandia research paper accepted for publication by Physical Review Letters (PRL). To exceed scientific break-even is the most hotly sought-after goal of fusion research, in which the energy released by a fusion reaction is greater than the energy put into it — an achievement that would have extraordinary energy and defense ...

Further steps needed to reduce stigma and expand access to substance abuse

2012-09-17
WASHINGTON — Outdated approaches to preventing and treating substance abuse, barriers to care, and other problems hinder the U.S. Defense Department's ability to curb substance use disorders among military service members and their families, says a new report from the Institute of Medicine. Service members' rising rate of prescription drug addiction and their difficulty in accessing adequate treatment for alcohol and drug-related disorders were among the concerns that prompted members of Congress to request this review. "We commend the steps that the Department of Defense ...

Berkeley Lab sensors enable first light for the dark energy camera

Berkeley Lab sensors enable first light for the dark energy camera
2012-09-17
Early in the morning of September 12 the Dark Energy Camera (DECam), mounted on the Victor Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile, recorded its first images of a southern sky spangled with galaxies. Galaxies up to eight billion light years away were captured on DECam's focal plane, whose imager consists of 62 charge-coupled devices (CCDs) invented and developed by engineers and physicists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab). Berkeley Lab CCDs are noted for their exceptionally high ...

World's most powerful digital camera opens eye, records first images in hunt for dark energy

2012-09-17
Eight billion years ago, rays of light from distant galaxies began their long journey to Earth. That ancient starlight has now found its way to a mountaintop in Chile, where the newly constructed Dark Energy Camera, the most powerful sky-mapping machine ever created, has captured and recorded it for the first time. That light may hold within it the answer to one of the biggest mysteries in physics – why the expansion of the universe is speeding up. Scientists in the international Dark Energy Survey collaboration announced this week that the Dark Energy Camera, the ...

Improving memory for specific events can alleviate symptoms of depression

2012-09-17
Hear the word "party" and memories of your 8th birthday sleepover or the big bash you attended last New Year's may come rushing to mind. But it's exactly these kinds of memories, embedded in a specific place and time, that people with depression have difficulty recalling. Research has shown that people who suffer from, or are at risk of, depression have difficulty tapping into specific memories from their own past, an impairment that affects their ability to solve problems and leads them to focus on feelings of distress. In a study forthcoming in Clinical Psychological ...

Home Security That's a Perfect Fit for Your Lifestyle

2012-09-17
LifeShield Security is proud to announce LifeShield Lifestyles, a unique tool to help consumers to choose home security systems and products that fit their routines and personalities. By offering security systems that are designed for individuals, families, and real-life situations, LifeShield is continuing its mission to go "beyond the alarm" and provide advanced technology wireless security and peace of mind. "Home security is really about people, not houses. Homeowners and renters don't install alarm systems to protect walls, ceilings and doors. They ...

Flu antibody’s 'one-handed grab' may boost effort toward universal vaccine, new therapies

Flu antibody’s one-handed grab may boost effort toward universal vaccine, new therapies
2012-09-17
LA JOLLA, CA -- Scientists from The Scripps Research Institute and Sea Lane Biotechnologies have solved the co-crystal structure of a human antibody that can neutralize influenza viruses in a unique way. The antibody recognizes the crucial structure that flu viruses use to attach to host cells, even though previously this structure had been thought too small for an antibody to grab effectively. The immune protein manages to hit this precise spot by using just a small part of its target-grabbing apparatus. In so doing, it can neutralize a broad range of dangerous flu viruses. "This ...

Most coral reefs are at risk unless climate change is drastically limited

2012-09-17
Only under a scenario with strong action on mitigating greenhouse-gas emissions and the assumption that corals can adapt at extremely rapid rates, could two thirds of them be safe, shows a study now published in Nature Climate Change. Otherwise all coral reefs are expected to be subject to severe degradation. Coral reefs house almost a quarter of the species in the oceans and provide critical services – including coastal protection, tourism and fishing – to millions of people worldwide. Global warming and ocean acidification, both driven by human-caused CO2 emissions, ...

LAST 30 PRESS RELEASES:

Climate crisis could force wild vanilla plants and pollinating insects apart, threatening global supply

Teens report spending 21% of each driving trip looking at their phone

Study explores the ‘social norms’ of distracted driving among teens

Diver-operated microscope brings hidden coral biology into focus

Enhancing the “feel-good” factor of urban vegetation using AI and street view images

A single genetic mutation may have made humans more vulnerable to cancer than chimpanzees

Innovative nanocomposite hydrogel shows promise for cartilage regeneration in osteoarthritis treatment

2025 Guangci Laboratory Medicine Innovation and Development Conference

LabMed Discovery is included in the ICI World Journals database

LabMed Discovery is included in the China Open Access Journal (COAJ) database

Vaccination support program reduces pneumonia-related mortality by 25 percent among the elderly

Over decades, a healthy lifestyle outperforms metformin in preventing onset of Type 2 diabetes

Mental health disorders, malaria, and heart disease most affected by covid pandemic

Green transition will boost UK productivity

Billions voted in 2024, but major new report exposes cracks in global democracy

Researchers find “forever chemicals” impact the developing male brain

Quantum leap in precision sensing across technologies

Upgrading biocrude oil into sustainable aviation fuel using zeolite-supported iron-molybdenum carbide nanocatalysts

For effective science communication, ‘just the facts’ isn’t good enough

RT-EZ: A golden gate assembly toolkit for streamlined genetic engineering of rhodotorula toruloides

Stem Cell Reports announces five new early career editors

Support networks may be the missing link for college students who seek help for excessive drinking

The New England Journal of Medicine shines spotlight on forensic pathology

Scientists discover protein that helps lung cancer spread to the brain

Perceived social status tied to cardiovascular risks in women but not in men

Brain tumor growth patterns may help inform patient care management

This might be America's first campus tree inventory

Emoji use may impact relationship outcomes

Individual merit, not solidarity, prioritized by early childhood education policies

Preclinical study unlocks a mystery of rapid mouth healing

[Press-News.org] When it rains, it pours
Study estimates rate of intensification of extreme tropical rainfall with global warming