Taking advantage of the new world order, U.S. scientists have finally gathered hard evidence to explain the Bennett Island plumes, a mystery that remained unsolvable during the Cold War.
But the long-sought explanation has proved less exciting than experts had
Taking advantage of the new world order, U.S. scientists have finally gathered hard evidence to explain the Bennett Island plumes, a mystery that remained unsolvable during the Cold War.
But the long-sought explanation has proved less exciting than experts had hoped. The Bennett Island plumes apparently result from air streams passing over low mountains on the island, reports Russell C. Schnell, an atmospheric scientists who coordinated the recent aircraft experiment above the island.
Scientists would have liked to find evidence to the contrary. "Deep in my heart of hearts, I still hope they're not orographic [mountain-caused] clouds," says Schnell, director of the National Oceanic and Atmospheric Administration's monitoring station in Hilo, Hawaii.
First spotted on satellite images in 1983, the plumes are extremely thin cloud trails stretching hundreds of kilometers downwind of tiny Bennett Island, located in the East Siberian Sea. Atmospheric scientists put forward several explanations for the ephemeral contrail-like plumes, including the possibility that they resulted from Soviet activity in what was then a militarily sensitive area. At the time, western investigators could not hope to visit Bennett Island to test their ideas. In the absence of direct data, they settled on the hypothesis that the plumes originated from leaking deposits of frozen methane, known to exist beneath the floor of the Arctic Sea (SN: 3/28/87,p.204).
Such methane plumes might have economic implications if they signaled the presence of large natural gas reserves located close to the ocean floor. But the leaks could also have an ominous message, suggesting that global warming had started melting the frozen subsea stores of methane in the Arctic.