> Deborah Harrell <[EMAIL PROTECTED]> wrote: > > Andrew Crystall <[EMAIL PROTECTED]> wrote:
> > ...Global Dimming, caused by particulate and other > > emissions fom Human > > industry has hidden much of the effect of global > > warming - to the > > tune of 5C or even more. http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml > I'd heard about this from someone consulting at an > Arizona solar power plant (not sure if it was > experimental or fully operational) several years > ago....I'll see if I can get > more info from my source. From http://science.nasa.gov/headlines/y2006/03oct_novarupta.htm?list91324 In June 1912, Novarupta—one of a chain of volcanoes on the Alaska Peninsula—erupted in what turned out to be the largest blast of the twentieth century. It was so powerful that it drained magma from under another volcano, Mount Katmai, six miles east, causing the summit of Katmai to collapse to form a caldera half a mile deep. Novarupta also expelled three cubic miles of magma and ash into the air, which fell to cover an area of 3,000 square miles more than a foot deep... [there's a pic at the site, also a graph] ...When a volcano anywhere erupts, it does more than spew clouds of ash, which can shadow a region from sunlight and cool it for a few days. It also spews sulfur dioxide. If the eruption is strongly vertical, it shoots that sulfur dioxide high into the stratosphere more than 10 miles above Earth. Up in the stratosphere, sulfur dioxide reacts with water vapor to form sulfate aerosols. Because these aerosols float above the altitude of rain, they don't get washed out. They linger, reflecting sunlight and cooling Earth's surface. This can create a kind of nuclear winter (a.k.a. "volcanic winter") for a year or more after an eruption. In April 1815, for instance, the Tambora volcano in Indonesia erupted. The following year, 1816, was called "the year without a summer," with snow falling across the United States in July... ...But both those volcanoes as well as Krakatau were in the tropics; Novarupta is just south of the Arctic Circle... ...This bottling up of Novarupta's aerosols in the north would make itself felt, strangely enough, in India. According to the computer model, the Novarupta blast would have weakened India's summer monsoon, producing "an abnormally warm and dry summer over northern India," says Robock... ...Robock and colleagues are examining weather and river flow data from Asia, India, and Africa in 1913, the year after Novarupta. They are also investigating the consequences of other high-latitude eruptions in the last few centuries... Debbi who fortuitously read that NASA mewsletter today __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
