Category: Doherty Earth Observatory
The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. Now, the first year-by-year accounting of this mechanism during the industrial era suggests the oceans are struggling to keep up with rising emissions -- a finding with potentially wide implications for future climate.
WASHINGTON -- NASA begins a series of flights Oct. 15 to study changes to Antarctica's sea ice, glaciers and ice sheets. The flights are part of Operation Ice Bridge, a six-year campaign that is the largest airborne survey ever made of ice at Earth's polar regions.
Results of a new study add evidence that climate swings in the northern hemisphere over the past 12,000 years have been tightly linked to changes in the tropics.
DURHAM, N.H. -- A new study that reports precise ages for glacial moraines in southern Peru links climate swings in the tropics to those of Europe and North America during the Little Ice Age approximately 150 to 350 years ago.
Flying twin-engine light aircraft the equivalent of several trips around the globe and establishing a network of seismic instruments across an area the size of Texas, a U.S.-led, international team of scientists has not only verified the existence of a mountain range that is suspected to have caused the massive East Antarctic Ice Sheet to form, but also has created a detailed picture of the rug
For years, researchers have examined climate records indicating that millennial-scale climate cycles have linked the high latitudes of the Northern hemisphere and the subtropics of the North Pacific Ocean. What forces this linkage, however, has been a topic of considerable debate. Did the connection originate in the North Pacific with the sinking of oxygen-rich waters into the interior of the ocean during cool climate intervals, or did it originate in the subtropical Pacific with the transfer of heat between the ocean and the atmosphere?
Over the last four decades, scientists have observed a 1.3% per decade decline in the amount of sun reaching the Earth's surface. This phenomenon, coined ''solar dimming'' or ''global dimming,'' is due to changes in clouds and air pollution that are impeding the suns ability to penetrate. Scientists believe that the combination of growing quantities of man-made aerosol particles in the atmosphere and more moisture are causing the cloud cover to thicken.
Dust from China's Takla-Makan desert traveled more than 20,000 kilometers [12,000 miles] in about two weeks, crossing the Pacific Ocean, North America, and the Atlantic Ocean, before settling atop the French Alps. Chinese dust plumes had been known to reach North America and even Greenland, but had never before been reported in Europe.
On June 18, 2002, a magnitude 5.0 earthquake occurred in southern Indiana, followed by a 1.2 magnitude aftershock on June 25, 2002. Because the region of occurrence, the Wabash Valley Seismic Zone, is seismically active, Dr. Won-Young Kim, a seismologist with the Lamont-Doherty Earth Observatory at Columbia University, conducted research to determine the potential hazard of future earthquakes to this region. His findings suggest that an ancient fault line dating back to the Precambrian era of geological history (from 4.6 billion to 570 million years ago) has become reactivated and was the likely cause of the June 2002 earthquakes. Kim is presenting his findings at the Seismological Society of America in May, and publishing in the Bulletin of the Seismological Society of America.
Detection techniques and technology have improved so much in recent years that seismologists now say they are able to detect and identify virtually all events that might be nuclear explosions of possible military significance under the Comprehensive Test Ban Treaty. Verification was a major issue in the U.S. Senate debate in 1999, in which American ratification of the treaty was defeated.
