 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
One More Way Cosmic Rays Can Ruin Your Day
Washington - Jul 31, 2002 Researchers studying global warming have often been confounded by the differences between observed increases in surface-level temperatures and unchanging low-atmosphere temperatures. Due to this discrepancy, some have argued that global warming is unproven, suggesting instead that true warming should show uniformly elevated temperatures from the surface through the atmosphere. Researchers have proposed a theory that changes in cloud cover could help explain the puzzling phenomenon, but none-until now-have come up with an argument that could account for the varying heat profiles. A study in the July 2002 issue of Journal of Geophysical Research-Space Physics, published by the American Geophysical Union, proposes for the first time that interstellar cosmic rays could be the missing link between the discordant temperatures observed during the last two decades (since recorded satellite records began in 1979). The report, by Fangqun Yu of the State University of New York-Albany, proposes that the rays, tiny charged particles that bombard all planets with varying frequency depending on solar wind intensity, may have height-dependent effects on our planet's cloudiness. Previous research has proposed a link between cosmic rays and cloud cover, has not suggested the altitude dependence of the current study. "A systematic change in global cloud cover will change the atmospheric heating profile," Yu said. "In other words, the cosmic ray-induced global cloud changes could be the long-sought mechanism connecting solar and climate variability." The hypothesis, if confirmed, could also shed light on the Sun's role in global warming. Theamount of cosmic rays reaching Earth depends on solar winds, which vary in strength by space-weather conditions. Yu points out that indications of Earth's warming have coincided with decreased cosmic ray intensity during the 20th century. Such explanations for natural causes of global warming do not rule out human contributions to temperature change, but present the possibility that humans are not solely responsible for some of the observed temperature increases. In addition, recent satellite data have revealed a correlation between cosmic ray intensity and thefraction of the Earth covered by low clouds. Yu proposes that the amount and charge of cosmic ray-generated ions can contribute to the formation of dense clouds by stimulating the production rate of low-atmosphere particles that make the clouds more opaque. In addition, natural and man-made differences in atmospheric chemistry, like greenhouse gas concentrations, can also affect the cosmic rays' influence on clouds, according to Yu. Such height-dependent atmospheric differences can increase the quantity of ambient particles in the lower troposphere and decrease the particles in the upper air, thus affecting the type of cloud cover. High clouds, for example, generally reflect sunlight while lower clouds tend to retain surfaceenergy; both effects are scientifically well established and have a significant effect on global temperatures. The data provides evidence supporting Yu's claim that cosmic ray-induced cloud changes may have warmed the Earth's surface but cooled the lower troposphere, which could provide an explanation of the Earth's varying temperature trends. The paper, Fangqun Yu, "Altitude variations of cosmic ray induced production of aerosols:Implications for global cloudiness and climate," appears in Journal of GeophysicalResearch-Space Physics, published by the American Geophysical Union. Citation to the on-line version is: 10.1029/2001JA000248. Community Email This Article Comment On This Article Related Links Atmospheric Sciences Research Center at Albany SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Dirt, rocks and all the stuff we stand on firmly
Magnetic Reconnection Region Larger Than 2.5 Million Km Found In The Solar Wind
Paris (ESA) Jan 12, 2006Using the ESA Cluster spacecraft and the NASA Wind and ACE satellites, a team of American and European scientists have discovered the largest jets of particles created between the Earth and the Sun by magnetic reconnection. This result makes the cover of this week's issue of Nature. |
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement |
