Changes In Winds Could Have Been Cause Of Abrupt Glacial Climatic Change

Changes In Winds Could Have Been Cause Of Abrupt Glacial Climatic Change

ScienceDaily (July 21, 2008) — Spanish and German researchers have carried out a collaborative study that shows how during the last glacial period, small variations in the surface winds could have induced significant changes in the oceanic currents of the North Atlantic, and could even have played a role in the abrupt climate change that occurred at the time.

Scientists from the Complutense University of Madrid (UCM) and the Potsdam-Institute for Climate Impact Research in Germany have carried out a study which identifies small alterations in the superficial sea winds as the factors with a key role in the abrupt climatic change that occurred over the last glacial period whose origin is not yet fully understood.

This study, carried out by researchers Marisa Montoya and Anders Levermann, concluded that there is a precise point from which a small variation in the speed of sea winds corresponds to a dramatic change in the Atlantic circulation intensity. According to Marisa Montoya, “If the glacial climate had been in the vicinity of that point, small wind changes could have caused sudden and significant climatic changes during that period”

The study was based on climatic simulations called Last Glacial Maximum (LGM) (the period of maximum extension of the perpetual ice sheets that took place over 21.000 years ago). These simulations have demonstrated the existence of a threshold after which a small change in wind speed causes disproportionately large changes in the sea current speed. The results indicate that these changes in wind speed could have had a particularly important role in the abrupt climatic change of the last ice age.

Climate simulation of the Last Glacial Maximum is one of the principal challenges for experts in this area. The comparison of results from these simulations with climatic reconstructions based on data gathered from natural elements, such as sea sediments or the oldest ice samples; permit the evaluation of the climatic models in conditions independent from the ones used for their design. The results confirm the relevance of the small variations and help further substantiate the hypothesis about the physical mechanisms responsible for the climatic changes observed in the reconstructions.

Both, the climatic simulations as well as the reconstructions, indicate that variations in the Atlantic Ocean circulation could have been the key mechanism responsible for the abrupt climatic change that took place over the ice age. This circulation plays a fundamental role in the regulation of climate on a global scale, since it transports large quantities of relatively warm water from low latitudes to northern regions, softening the climate of countries like Norway or Ireland in comparison with other regions in the same latitude, but with much harsher climates, like Alaska or New York. This study therefore suggests that the changes in oceanic circulation could have been caused by changes in the speed of surface winds.

WEATHER NOTE

Weather radio's early warnings can be lifesavers

August 11, 2008

By Erik Potter Post-Tribune staff writer

Eleven minutes.

For about $50, a weather radio could have given Griffith residents an 11-minute heads-up that a destructive, potentially deadly tornado was bearing down on their town.

"(That) can be a long time," professor Bart Wolf, chairman of Valparaiso University's geography and meteorology department, said. "That can mean the difference between life and death if it's a bad enough storm."

It could mean the difference between getting caught in an upstairs bedroom or finding shelter in the basement.

At 8:17 p.m. Monday, 11 minutes before the twister began brawling its way through Griffith, a tornado alert went out from the National Weather Service office in Chicago. It was immediately broadcast across Lake County from the local weather transmitter in Hebron.

"At 8:16 p.m., National Weather Service radar indicated strong rotation in a severe thunderstorm near Calumet City, moving east at 59 mph," the alert said. "The tornado will be near Highland, Griffith, and eight miles north of Schererville by 8:25 (p.m.)."

If you hadn't already run for the basement by then, the alert went on to say that you should run directly to the basement, avoiding any windows on the way if possible.

"All-hazard alert" radios have come a long way in the past decades.

More than just alerting to severe weather, the electronic boxes will squawk when there's a flooding alert, a chemical spill or other environmental hazard, or a terrorist threat or attack.

Moreover, the newer radios can be programmed to sound the alarm for specific counties.

The new Specific Area Message Encoding. weather radios can be told to wail only when there's an alert for the county you live in.

The Hebron transmitter covers Lake, Porter, LaPorte, Newton, Jasper, Pulaski and Starke counties, so the ability to narrow the information that the radio gives out is helpful for the Porter County resident who doesn't want to hear about flash-flood alerts in Starke County at 2 a.m.

And while there are 53 tornado sirens in Porter County and several sirens in at least nine Lake County communities that offer free tornado warnings, these outdoor sirens have one major drawback: they're meant for people outdoors.

If you're sitting inside watching a DVD, said Phil Griffith, director of the Porter County Emergency Management Agency, you're probably not going to hear the siren. If you're watching a DVD, you're not going to see the severe weather logo and information crawling along the bottom of your TV screen.

A weather radio can fill that gap between the media warnings and tornado sirens.

"A weather (radio) alert is the way to go indoors," Griffith said.

Weather radios can be purchased at many area retailers, including Radio Shack and Best Buy.

Contact Erik Potter at 648-3120, or epotter@post-trib.com. Comment on this story at www.post-trib.com.

If you buy one

The new Specific Area Message Encoding, or S.A.M.E., weather radios allow you to program county codes so you receive alerts only for the counties you're interested in. The radio transmitter serving Northwest Indiana is WNG 689 in Hebron, operating at 162.450 MHz. The S.A.M.E. codes for this area are:

Lake 018089

Porter 018127

Newton 018111

Jasper 018037

LaPorte 018091

Starke 018149

Pulaski 018131

MARITIME NOTE

Coast Guard Responds to Fishing Vessel Around on Flemming Island

JUNEAU, Alaska - The Coast Guard Marine Safety Unit in Valdez, Alaska has responded to and is investigating the grounding of the fishing vessel Northern Mariner, which ran aground on the north side of Flemming Island Thursday night.

Two overflights by Alyeska and a Coast Guard helicopter from Air Support Facility Cordova revealed that the Northern Mariner is partially submerged at high tide and there is a 6-foot by two-foot sheen coming from the vessel. The sheen is believed to be from residual oil from the engine room.

The grounded vessel has 25,000 gallons of diesel, 50 gallons lube oil and 300 gallons of hydraulic oil. Fuel tanks are believed to be intact.

There is a reported one-foot hole in the hull and the engine room is flooded.

Three hundred feet of containment boom has been placed around the vessel by responders from Alaska Chadux.

Ship Escort/Response Vessel System’s (SERVS) vessels arrived in the area Friday morning and deployed protective staging in the vicinity of the salmon hatchery in Sawmill Bay and the adjacent village of Chenega, Alaska. SERVS also transported bladders for lightering operations and are standing by.

R&R Diving deployed two vessels and personnel to prepare pumps for lightering the fuel oil and plan to start late Friday afternoon as tanks arrive to hold the oils.

The owner is also working to determine the status of and appropriate disposition of over 350,000 pounds of pink salmon that was onboard.

A Coast Guard Marine Inspector and a pollution investigator are on scene to monitor lightering and salvage operations. Coast Guard, Alaska Department of Environmental Conservation and owner’s representatives have established a command post at the Marine Safety Unit in Valdez to coordinate all activities.

The Northern Mariner, a 110-foot fishing vessel homeported in Seattle, began taking on water Thursday night with four people aboard. The crew then intentionally grounded the vessel to keep it from sinking and abandoned the vessel in a life raft. The Good Samaritan vessel Tenacious recovered all four crewmembers safely and transported them to Whittier.

The cause of the vessel taking on water and the subsequent grounding are being investigated.

RS