Weather Front

By Anonymous

Sea Cucumbers, Ice Fish, and Sea Squirts, Oh My! The fact that Antarctic ice shelves are melting is far from breaking news, but what lies beneath in their newly uncovered waters just might be.

Thanks to the disintegration of thousands of miles of ice shelves over the past 30 years, scientists are getting to know the residents of the once ice-covered waters of the Weddell Sea. Previously, because of the massive size of the shelves, scientists were unable to get up close and personal with the wide variety of life lurking underneath the ice.

A team of scientists hailing from 14 countries made a 10-week trip to the Weddell Sea area, and was greeted with a bounty of creatures. At a depth of 2,800 feet below the surface the team found some incredible creatures: a blue fish that adapts to its frigid climate with blood that lacks red blood cells, a long-limbed sea star with more than the usual five limbs, sea cucumbers that travel in large packs, and thick settlements of the gelatinous sea squirt. These sea squirts are believed to be newcomers to the area, having arrived after the shelf collapse.

The team also alighted upon 19 potentially undiscovered species of amphipods and cnidarians. Further analysis will indicate whether or not these species were discovered previously.

Hot Plants

Since 1981, the world’s farmers have lost nearly $5 billion in revenue on major cereal crops because of rising temperatures worldwide, according to a study published online by Environmental Research Letters. The study, led by David Lobell of Lawrence Livermore National Laboratory, is the first to estimate the impact of climate change on global food production. Yearly global temperatures increased by 0.7[degrees]F between 1980 and 2002, and some regions have experienced even larger increases.

To determine the impact of these changes, Lobell and his colleagues studied the six most common crops: wheat, rice, maize, soybeans, barley, and sorghum. Together, these cereals account for more than 40 percent of the cropland on the planet, as well as 55 percent of non-meat calories consumed and more than 70 percent of animal feed. The researchers compared global yield data from the Food and Agriculture Organization for 1961-2002 with average temperatures and precipitation over the major growing areas.

According to the study’s findings, the average global crop yields for several of the grains responded negatively to warmer temperatures. By assuming that farmers have not yet adapted to climate change, Lobell and colleagues were able to estimate that yields dropped by about 3 to 5 percent for each 1[degrees]F increase in temperature.

“There is clearly a negative response of global yields to increased temperatures,” Lobell said. “Though the impacts are relatively small compared to the technological yield gains over the same period, the results demonstrate that negative impacts of climate trends on crop yields at the global scale are already occurring.” He added, “A key [to] moving forward is how well cropping systems can adapt to a warmer world. Investments in this area could potentially save billions of dollars and millions of lives.”

Christopher Field, co-author of the study and director of the Carnegie Institution’s Department of Global Ecology, said, “Most people tend to think of climate change as something that will impact the future, but this study shows that warming over the past two decades already has had real effects on global food supply.”

Smart Mud

Pending funding from the International Continental Drilling Programme, researchers from the University of Bonn, Germany, will be plunging a drill core 250 meters into the bed of Lake Van, in Turkey, 380 meters underwater. Their goal is to access 800,000 years of history and climatological data, encased in approximately 400 meters of mud, on the lake’s floor.

Each summer, a layer of lime-calcium carbonate drifts to the lakebed floor, sealing a season’s worth-or millions and millions of grains-of pollen and detritus. In the winter, a similar layer of clay falls to the floor. These alternating layers effectively seal, preserve, and timestamp the ecological artifacts from another time.

Because the grains of pollen are so well preserved, it is possible to divine climatic information, such as temperature and average amounts of precipitation, from their shells and insides. Preliminary research already has indicated that the climate has, at times, suddenly changed within as little as 10 or 20 years. “If we find pollen in a speciman from a different species whose demands on its habitat are known we can make a plausibility statement about the nature of the climate of the time,” said Bonn paleontologist Thomas Litt. “We presume that the bottom of Lake Van stores the climate history of the last 800,000 years, an incomparable house of data which we want to tap for at least the last 500,000 years.”

The lakebed layers also give indications of volcanic eruptions. Preliminary testing has shown that there have been 15 eruptions over the past 20,000 years, and the composition of ash indicates the nearby volcano from which it originated.

Rivers in the Air

In an effort to help prevent the catastrophic floods that periodically hit Sacramento, California, and other urban areas, the NOAA Earth System Research Laboratory is conducting a study of the air, water, and soil in the American River basin, which spans the area between Sacramento and Reno, Nevada. The Sacramento region is one of the most flood-prone urban areas in the United States because prolonged winter rains can inundate the area and overwhelm levees. In 1996-1997 and 1998, streets were submerged in up to 20 feet of water as multiple levees broke.

NASA is hoping its new research will help provide local water managers with more accurate warnings to give them time to prepare for a potential flood. The study, called Hydrometeorology Testbed, uses new sensors, computer models, and other tools to help improve rain forecasts in California.

One of the most important aspects of the study is research into a West Coast climate pattern called “atmospheric rivers,” or ARs. These ARs are long bands of moisture that stretch over the Pacific Ocean and carry 95 percent of the water vapor transported annually from the tropics to the mid-latitudes. These weather systems are responsible for the flooding rains that periodically inundate California, Oregon, and Washington.

In a previous study, NOAA researchers found that every major flood analyzed during the period of study was related to an AR that caused storms to dump more than twice as much precipitation on coastal mountain ranges as all other storms combined. Some 20-35 ARs reach the West Coast each winter, and more than 100 each summer, although the summertime ARs result in little rainfall in part because of lower humidity.

Marty Ralph, a NOAA Earth System Research Lab scientist, is creating an intensity scale that will help meteorologists identify strong ARs and warn of potential flooding rains. Ralph said he expects ARs to become more powerful as the climate changes and the warmer atmosphere holds more water vapor.

HMT project manager Tim Schneider added, “We want a reliable prediction so we can say with confidence, ‘A week from now, we’re expecting a flood that will-signficantly threaten the levees.”

The Sands of Time

So, it looks like all those years spent digging in the playground’s sandbox have finally come in handy for a couple of lucky scientists. Curious about prehistoric hurricanes, Kam-biu Liu, George William Barineau III Professor at Louisiana State University’s Department of Oceanography and Coastal Sciences, headed a research team to find out if, when, and how many Category 4 or 5 storms have struck the U.S. Gulf Coast in the the past 3,800 years.

Knowing that only storms of a certain strength can toss sand and sediment inland to coastal lakes, Liu and his team conducted radiocarbon analysis and other dating techniques on sediment cores from these lakes.

The sediment cores revealed that hurricanes of catastrophic magnitudes have slammed into the Gulf Coast 10-12 times in the past 4 millennia. “That means the chances of any particular Gulf location being hit by a Category 4 or Category 5 hurricane in any given year is around 0.3 percent,” said Liu. Hurricane Katrina was a Category 3 storm.

After 15 years spent intensively researching lakes and marshes along the U.S. Gulf and Atlantic coasts, Liu and his students are now focusing on historic hurricanes that struck the Caribbean. They are also investigating how Hurricane Mitch, which struck Honduras and Nicaragua in 1998, killing 12,000 people, impacted the environment and local communities.

Other institutions participating in study, dubbed Paleotempestology of the Carribean Region, include the Woods Hole Oceanographic Institution, Brown University, Boston College, the University of Tennessee, the University of Toronto, the Memorial University of Newfoundland, the University of Costa Rica, and the Instituto Mexicano de Tecnologia del Agua, in Mexico.

NOAA at the Iditarod

The Iditarod is a legendary race, where racers (also known as mushers) guide their dogs through the frozen wilds of Alaska’s wintry land in an extreme test of fortitude and toughness. While it’s always exciting, Iditarod 2007 had a little something mus installments. This time, the “Last Great Race on Earth” partnered up with NOAA to highlight four Alaskan cities recently awarded the organization’s StormReady(R) designation. What does it take to have the StormReady title bestowed on a city? Among other criteria, NOAA requires a 24-hour warning point and emergency operations center, multiple ways to receive and transmit severe and emergency weather forecasts to the public, a special system put in place to monitor local weather conditions, events such as public seminars for establishing community awareness, and a formal plan for tackling severe weather.

The 1,150-mile sled race began on Sunday, March 3, in Willow, Alaska. All four StormReady cities were incorporated in the race, either as headquarters or stops on the trail itself. Kickoff festivities for the famous dogsled race, which can take about 10 days to complete, began at StormReady Anchorage. McGrath and Nome, which are two other StormReady cities, were stops along the course, and Wasilla served as an Iditarod headquarters site.

Since the program began in 1999, NOAA has already granted over 1,100 sites the StormReady seal of approval, but “nowhere is there more concern about weather safety than in Alaska where people live in vulnerable communities and face particular ravages of nature, including flooding, coastal erosion, blizzards, severe storms, and bitter cold,” said Jeffrey Osiensky, deputy chief of the National Weather Service Alaska Region Environmental Scientific Services division. In total, Alaska has nine cites with the StormReady designation.

Other StormReady locations in the United States include New York City, Orlando, San Francisco, and Seattle.

A Healing Atmosphere

We all know that the Earth’s ozone layer has been taking a beating for a while, but did you know that this same depleted ozone might be healing? According to a new study funded by NASA and led by Eun-Su Yang, a research scientist at the Georgia Institute of Technology, that’s just what seems to be happening.

The researchers analyzed data from three NASA satellites: SAGE I and II and HALOE. These satellites gathered data from 1979-2005, with the exception of a 3-year gap in the 1980s. Complementary data for the study were provided by ground-based measurements from NASA and NOAA, as well as balloons.

Researchers found that two regions of the lower stratosphere are showing promising improvements: one region is no longer seeing a decrease in the ozone, while the other shows signs of increased levels of ozone.

Researchers suggest that the Montreal Protocol of 1987 and its subsequent amendments have played a vital role in the stabilization of the ozone in the 18- to 25-kilometer (11- to 15-mile) altitude region. Derek Cunnold, a professor of earth and atmospheric sciences at the Georgia Institute of Technology and a contributor to the study, said, “[W]e believe there is some tendency toward an increase in ozone in this region, though further study is needed to be certain.”

The Montreal Protocol mandated massive reductions in the use of chlorofluorocarbons, which can come from spray-can propellants, refrigerator coolants, and foam insulaton. It also mandated the reduction of other harmful chemicals that were instrumental in the breakdown of the ozone.

“We do think we’re on the road to recovery of stratospheric ozone,” said Cunnold. However, he noted, “What we don’t know is exactly how that recovery will happen. Many in the scientific community think it will be at least 50 years before ozone levels return to the pre-1980 levels when ozone began to decline.”

The researchers did not attribute the increase in ozone in the 11- to 18- kilometer (7- to 11-mile) altitude region to the Montreal Protocol and the consequent change in atmospheric chemistry, but rather to atmospheric transport, which is the movement of chemical species through the atmosphere. These changes contribute significantly, by about half, to the overall measured improvements.

Ross Salawitch of NASA’s Jet Propulsion Laboratory at the California Institute of Technology said, “Our study provides a quantitative measure of a key fingerprint that is lacking in earlier studies-the response of the ozone layer as function of height.”

The study was published in the September 9 issue of the American Geophysical Union’s Journal of Geophysical Research-Atmospheres.

Lucky Strike

Some 15,000 years ago, the bare desert of southwestern Egypt was home to a number of grasses and shrubs that are similar to what now grows in southwestern Niger, according to a study published in the February issue of Geology. For the study, Rafael Navarro-Gonzalez, a geochemist at the National Autonomous University of Mexico in Mexico City, and colleagues conducted the first tests on the chemical compositions of gas bubbles trapped in fulgurites, which are tubular glass masses created by the fusion of sand resulting from a lightning strike.

Thunderstorms are rare in the desert of southwestern Egypt today, but the number of fulgurites that have been found in the area suggests that lightning was a frequent weather phenomenon on the sand dunes in the past. For their research, Navarro-Gonzalez and his team conducted chemical analyses of the gases trapped in the bubbles inside the fulgurites. They found that the bubbles contained only a small amount of argon, which is the most abundant inert gas in the atmosphere today. In the fulgurite bubbles researchers found a carbon dioxide to argon ratio of 100:1, compared with a ratio of 1:25 in modern samples of Earth’s atmosphere.

The researchers theorized that the high concentration of carbon dioxide in the fulgurites was due to the vaporization of organic material by the lightning bolt when it fused the sand grains together. They said that the ratio of carbon-12 to carbon-13 isotopes found in the trapped gases would be normal for the photosynthesis of grasses and shrubs. As a result, Navarro- Gonzalez speculated that 15,000 years ago, around the time of the end of the latest Ice Age, the climate of southwestern Egypt was similar to that of modern Niger.

Hurricane Mitch at peak intensity on October 26, 1998, at 2028 UTC. Mitch had winds up to 180 mph

Copyright Heldref Publications May/Jun 2007

(c) 2007 Weatherwise. Provided by ProQuest Information and Learning. All rights Reserved.