Atmospheric News
Warmer Seas, Wetter Air Make Harder Rains as Greenhouse Gases Build
A National Center for Atmospheric Research (NCAR) study explains how and where a warmer atmosphere and oceans will produce more intense precipitation. The findings recently appeared in Geophysical Research Letters, published by the American Geophysical Union.
The greatest increases will occur over land in the tropics, the study says. Heavier rain or snow will also fall in northwestern and northeastern North America, northern Europe, northern Asia, the east coast of Asia, southwestern Australia, and parts of south-central South America during the 21st century.
NCAR authors Gerald Meehl, Julie Arblaster, and Claudia Tebaldi analyzed the results of nine atmosphere-ocean global climate models to explain the physical mechanisms involved as intensity increased. Precipitation intensity refers to the amount of rain or snow that falls on a single stormy day.
Find this press release and images on the Web at
http://www.ucar.edu/news/releases
back to top
New NCAR Supercomputer Slices Turnaround Time in Half
A new supercomputer at the National Center for Atmospheric Research (NCAR) will enable scientists to answer complex scientific questions in half the time. NCAR has nicknamed the computer Blue Vista.
NCAR will continue to operate its other supercomputers, an IBM POWER4-based machine and an IBM e1350 Linux Cluster, along with Blue Vista. The combined computational power of the three supercomputers places NCAR among the top 25 institutions worldwide as measured by computational capacity, estimates Tom Bettge, deputy director of NCAR's Scientific Computing Division.
The new machine's first challenge will be to study the effects of tropical convection on hurricanes and other tropical weather systems, using a regional climate model embedded in a global model. This work is relevant to the question of whether global climate change is helping produce more Category 4 and 5 hurricanes (the most powerful). The problem is so demanding, computationally, that it will occupy all of Blue Vista's available time from October through December.
The new machine is an IBM p575 based on IBM's POWER5 processor. It was delivered to NCAR in late August, and software installation began on September 6. Testing will continue throughout the fall.
The machine is smaller, denser, and hotter than its predecessor, the IBM POWER4-based unit. Blue Vista takes up only a third as much floor space as the older supercomputer but requires two-thirds as much power and cooling. Bettge estimates that Blue Vista will need over 250 kilowatts of power to operate. The average personal computer consumes 0.12 kilowatts.
The new processor, along with other design improvements, allows Blue Vista's internal "clock"—the number of operations it performs each second—to run about twice as fast as its predecessor.
The research on tropical convection is a major step forward in developing a model that can seamlessly move between studies of local weather and of global climate, using the correct scale for each type of problem. The study will also include research into the effects of ocean conditions on global weather.
For more on the new supercomputer see http://www.ucar.edu/news/releases/2005/bluevista.shtml
.
back to top
Global Array of Floats Nearly 2/3 Complete
Nearly two-thirds of the planned 3,000 free-floating Argo “robot oceanographers” are now in place, the National Oceanic and Atmospheric Administration says. The Argo observation program, which began in 2000, is part of the global observing system to monitor Earth’s oceans,
So far NOAA has collected nearly 55,000 profiles from the U.S. floats.
Argo is an internationally coordinated, broad-scale global array of temperature and salinity profiling floats, and a major component of the global ocean observing system.
The 54,447th Argo profile was transmitted October 5 on the Global Telecommunications System for use by the international oceanographic community. The floats are deployed from research vessels, volunteer merchant ships, and aircraft. Upon release, the floats sink to a prescribed depth (typically 1000 or 2000 meterss), remain submerged from 10 to 14 days, and then obtain temperature and salinity profiles of the water column on their return to the surface. Once on the surface, the floats transmit their data to satellites then repeat their data collecting cycle.
The international Argo program is supported by 18 nations and the European Commission.
More Argo information:
http://www.aoml.noaa.gov/phod/ARGO/HomePage/
http://www.argo.ucsd.edu/FrAbout_Argo.html
http://floats.pmel.noaa.gov/
back to top
GA Tech, NCAR Study Says Hurricanes Are Getting Stronger
A study by researchers at the Georgia Institute of Technology and the National Center for Atmospheric Research (NCAR) says the number of Category 4 and 5 hurricanes worldwide has nearly doubled over the past 35 years, even though the total number of hurricanes has dropped since the 1990s. The shift occurred as global sea surface temperatures have increased over the same period. The research appears in the September 16 issue of Science.
Peter Webster, professor at Georgia Tech's School of Earth and Atmospheric Sciences, along with NCAR's Greg Holland and Georgia Tech's Judith Curry and Hai-Ru Chang, studied the number, duration, and intensity of hurricanes (also known as typhoons or tropical cyclones) that have occurred worldwide from 1970 to 2004.
"What we found was rather astonishing," said Webster. "In the 1970s, there was an average of about 10 Category 4 and 5 hurricanes per year globally. Since 1990, the number of Category 4 and 5 hurricanes has almost doubled, averaging 18 per year globally."
The only region that is experiencing more hurricanes and tropical cyclones overall is the North Atlantic, where they have become more numerous and longer-lasting, especially since 1995. The North Atlantic has averaged eight to nine hurricanes per year in the last decade, compared to six to seven per year before the increase. Category 4 and 5 hurricanes in the North Atlantic have increased at an even faster clip: from 16 in the period of 1975-89 to 25 in the period of 1990-2004, a rise of 56%.
A study published in July in the journal Nature came to a similar conclusion. Focusing on North Atlantic and North Pacific hurricanes, Kerry Emanuel (Massachusetts Institute of Technology) found an increase in their duration and power, although his study used a different measurement to determine a storm's power.
But whether all of this is due to human-induced global warming is still uncertain, said Webster. He is currently attempting to determine the basic role of hurricanes in the climate of the planet. "The thing they do more than anything is cool the oceans by evaporating the water and then redistributing the oceans' tropical heat to higher latitudes," he said. "But we don't know a lot about how evaporation from the ocean surface works when the winds get up to around 100 miles per hour, as they do in hurricanes," said Webster, who adds that this physical understanding will be crucial to connecting trends in hurricane intensity to overall climate change.”
See http://www.ucar.edu/news/releases/2005/hurricanestudy.shtml
back to top
NOAA Winter Outlook Calls for Warmer than Normal Temps
The National Oceanic and Atmospheric Administration winter outlook for December, January and February calls for warmer-than-normal temperatures in most of the U.S. The precipitation outlook is less certain, showing equal chances of above, near or below normal precipitation for much of the country.
NOAA does not expect La Niña and El Niño/Southern Oscillation (ENSO) to play a role in this winter’s forecast. Without ENSO forecasters look to other short-term climate factors, like the North Atlantic Oscillation, in determining the overall winter patterns. According to NOAA, one key climate feature that could have a particularly large impact in U.S. winter weather, especially along the East Coast, is the North Atlantic Oscillation or NAO.
The North Atlantic Oscillation often changes its phase from week-to-week. During the positive phase the jet stream shifts to the north of its usual position and the winter weather features relatively warm days over much of the contiguous U.S. In contrast, during the negative phase the jet stream shifts to the south of its usual position. The negative phase of the NAO features more Nor’easters and more frequent cold air outbreaks and snowstorms, especially along the East Coast. Currently, the phase of the NAO is difficult to anticipate more than one to two weeks in advance.
The NOAA precipitation outlook calls for wetter-than-normal conditions across most of Arkansas, Louisiana, Oklahoma, and northeastern Texas. Drier-than-normal conditions are expected across the Southwest from Arizona to New Mexico. As winter approaches, nearly 20 percent of the nation is in some level of drought compared to around 30 percent of the country this time last year as defined by the U.S. Drought Monitor. For the sixth year in a row, drought remains a concern for parts of the Northwest and northern Rockies. Wet or dry conditions during the winter typically have a significant impact on drought conditions. Winter-spring snow pack is particularly important in the West, as much of the annual water supply comes from the springtime snow melt. NOAA cautions it would take a number of significant winter snowstorms to end the drought in the Pacific Northwest and northern Rockies.
For specific details see NOAA’s Climate Prediction Center: http://www.cpc.ncep.noaa.gov
back to top
Science Magazine Honors UCAR Team for Rip Current Visualizations
A Web development team from UCAR's Cooperative Program for Operational Meteorology, Education and Training (COMET) won an honorable mention in a contest sponsored by Science Magazine and the National Science Foundation. The team's entry in the noninteractive multimedia category of the Science and Engineering Visualization Challenge, titled Rip Currents: Nearshore Fundamentals, is an online, animated guide to the science of rip currents.
The contest celebrates the tradition of illustrating science with images, drawings, and animated presentations. Rip Currents: Nearshore Fundamentals helps users answer the question: Is it safe to go in the water? The COMET team developed the module for a broad audience that includes weather forecasters, researchers, and students. It provides a three-dimensional look at how rip currents form above and below the water's surface, with computer-generated breaking waves and capping sea foam. Topics covered include circulation and waves, rip current characteristics, and the forces that shape the currents.
See http://www.ucar.edu/news/releases/2005/ripcurrent.shtml
back to top
Mike Clancy Named Technical and Scientific Director of FNMOC
Following a competitive nationwide search, AMS member Mike Clancy has been chosen as Technical and Scientific Director of the U.S. Navy's Fleet Numerical Meteorology and Oceanography Center (FNMOC) in Monterey, CA. Clancy will serve as the senior civilian at FNMOC, and provide technical oversight and management of a broad spectrum of multi-disciplinary scientific, engineering and technical programs.
Clancy received a Bachelors Degree in Oceanography from Florida Institute of Technology in 1973, and a Masters Degree in Meteorology from the University of Miami in 1975. He worked for Science Applications Incorporated in the late '70s and the Naval Ocean Research and Development Activity (now part of the Naval Research Lab) in the early '80s. He joined FNMOC in 1983, where he has held a variety of technical and managerial positions.
back to top
Journal of the IEST Goes Online in October
Starting this month, the Institute of Environmental Sciences and Technology (IEST) annual Journal of the IEST will be available exclusively online. The Journal of the IEST is a technical journal for professionals in the environmental sciences.
The online format will offer an search feature and user-customizable settings. Journal subscribers and IEST members will have access to published peer-reviewed technical papers and Tech Talk technical articles containing the latest resource information for the environmental sciences community. The new online Journal will also include access to all technical papers published in the previous ten years. In addition to searchable, downloadable files, readers who register at the site will be able to request auto-notification when papers in their area of expertise are posted, save search criteria, and tag favorite publications.
More information is available online at www.iest.org or by calling IEST at (847) 255-1561.
back to top
MODELING OF LONG-TERM FOSSIL FUEL CONSUMPTION SHOWS 14.5 DEGREE HIKE IN TEMPERATURE
LIVERMORE, Calif. – If humans continue to use fossil fuels in a business as usual manner for the next several centuries, the polar ice caps will be depleted, ocean sea levels will rise by seven meters and median air temperatures will soar 14.5 degrees warmer than current day.
These are the stunning results of climate and carbon cycle model simulations conducted by scientists at the Lawrence Livermore National Laboratory. By using a coupled climate and carbon cycle model to look at global climate and carbon cycle changes, the scientists found that the earth would warm by 8 degrees Celsius (14.5 degrees Fahrenheit) if humans use the entire planet’s available fossil fuels by the year 2300.
The jump in temperature would have alarming consequences for the polar ice caps and the ocean, said lead author Govindasamy Bala of the Laboratory’s Energy and Environment Directorate.
In the polar regions alone, the temperature would spike more than 20 degrees Celsius, forcing the land in the region to change from ice and tundra to boreal forests.
“The temperature estimate is actually conservative because the model didn’t take into consideration changing land use such as deforestation and build out of cities into outlying wilderness areas,” Bala said.
Find this press release and images on the Web at: http://www.llnl.gov/pao/news/news_releases/2005/NR-05-11-01.html
back to top
|
