Earth Sciences

A paper published this week in the journal Science supports the hypothesis that heat transfer by ocean currents – rather than global heating or cooling – may have been responsible for the global temperature patterns associated with the abrupt climate changes seen in the North Atlantic during the past 80,000 years.

Authored by the University of Bremen’s Frank Lamy and colleagues, the paper provides new evidence that Southern Hemisphere climate may not have changed in step with Northern Hem

A new study shows that electron interactions may have nearly the same importance as chemical luminescence in exciting the atmospheric molecules that cause auroras. Campbell et al. suggest that nitric oxide molecules are promoted into potentially glowing, vibrational excited levels by a short-lived negative ion that is formed as a result of electron impact. Previous studies had reported that chemiluminescence, where nitrogen and oxygen molecules interact to form excited nitric oxide, was the main so

Elephants may be able to communicate over long distances but it’s hard to tell, because they’re not talking. Instead, they may be transmitting infrasonic signals through the ground with seismic waves. Gunther et al. studied the range of low-frequency vocal sounds made by African elephants and suggest that the signal’s two kilometer [one mile] range can propagate further than the animals’ airborne vocalizations.

Their study suggests that it is possible for elephants to communicate over long

Researchers have modified the European Incoherent Scatter Svalbard radar to potentially provide detailed information of even a single event in the polar ionosphere. Oksavik et al. demonstrate a new observation mode for the EISCAT instrument with the potential for monitoring small-scale flow variations in the Earth-space boundary. The authors used the technique to provide high-resolution data for the flow patterns surrounding a single poleward-moving auroral form (PMAF) event, a phenomenon ass

Including the atmospheric effects from volcanic eruptions in general circulation models may be the most important factor in improving the accuracy of long-term climate simulations. Vyushin et al. analyzed general circulation model estimates for the 20th century climate and found that volcanic eruptions, rather than the manmade effects from increasing greenhouse gas and aerosol levels, are the most significant factor in determining long-range correlations of surface air temperature. The author

An analysis of total solar irradiance data has allowed researchers to make the first detections of a solar flare from radiation-sensing satellites. Woods et al. report that total solar irradiance dropped by an unprecedented 0.34 percent during the strong solar storm in October-November 2003, because of large, dark sunspots observed by two NASA satellite missions. They also present data showing marked short-term solar radiation increases during one of the strongest X-class events seen during t