Frétt BBC: Geimgeislar hafa áhrif á trjávöxt í Bretlandi...

 

 

 

Í dag 19. október er á vef BBC fréttapistill sem nefnist Cosmic pattern to UK tree growth.

Pistillin fjallar um að breskir vísindamenn hafa fundið meiri fylgni milli vaxtarhraða trjáa og geimgeisla en hita eða úrkomu.  Þeir kunna ekki skýringu á þessu en hafa komið með tilgátur. Svo virðist vera að trén vaxi hraðar þegar geimgeislar eru miklir, en samkvæmt pistlinum þýðir það meira skýjaþykkni. Þá ætti einmitt að vera heldur svalara.    - Undarlegt.

 

Ef það er tilfellið að trén vaxi betur þegar skýjað er en í sólskini þá kemur það verulega á óvart. Getur það ekki þýtt að árhringir trjáa séu ekki eins góður mælikvarði á hitastig og talið var?  Það er auðvitað allt of snemmt að draga ályktanir, en þetta kemur óneitanlega á óvart.

Spyr sá sem ekki veit.  Fróðlegt verður að fylgjast með þessu máli.

 

 

Pistillinn byrjar þannig:

"The growth of British trees appears to follow a cosmic pattern, with trees growing faster when high levels of cosmic radiation arrive from space.

Researchers made the discovery studying how growth rings of spruce trees have varied over the past half a century.

As yet, they cannot explain the pattern, but variation in cosmic rays impacted tree growth more than changes in temperature or precipitation.

The study is published in the scientific journal New Phytologist.

"We were originally interested in a different topic, the climatological factors influencing forest growth," says Ms Sigrid Dengel a postgraduate researcher at the Institute of Atmospheric and Environmental Science at the University of Edinburgh...

... ...

When the intensity of cosmic rays reaching the Earth's surface was higher, the rate of tree growth was faster.

The effect is not large, but it is statistically significant.

The intensity of cosmic rays also correlates better with the changes in tree growth than any other climatological factor, such as varying levels of temperature or precipitation over the years.

"The correlation between growth and cosmic rays was moderately high, but the correlation with the climatological variables was barely visible," Ms Dengel told the BBC.

Here comes the Sun

Cosmic rays are actually energetic particles, mainly protons, as well as electrons and the nuclei of helium atoms, that stream through space before hitting the Earth's atmosphere.

The levels of cosmic rays reaching the Earth go up and down according to the activity of the Sun, which follows an 11-year cycle...

..."We tried to correlate the width of the rings, i.e. the growth rate, to climatological factors like temperature. We also thought it would be interesting to look for patterns related to solar activity, as a few people previously have suggested such a link," explains Ms Dengel. "We found them. And the relation of the rings to the solar cycle was much stronger than it was to any of the climatological factors we had looked at. We were quite hesitant at first, as solar cycles have been a controversial topic in climatology...""

Lesið meira á vef BBC

 

Humm... Humm...     

Þetta er ekki beinlínis eins og maður hefði átt von á.

 

http://news.bbc.co.uk/earth/hi/earth_news/newsid_8311000/8311373.stm

 

 --- --- ---

 

New Phytologist
A relationship between galactic cosmic radiation and tree rings

Sigrid Dengel, Dominik Aeby and John Grace

Institute of Atmospheric and Environmental Science, School of GeoSciences, Crew Building, University of Edinburgh, EH9 3JN, UK

ABSTRACT (krækja)

• Here, we investigated the interannual variation in the growth rings formed by Sitka spruce (Picea sitchensis) trees in northern Britain (55°N, 3°W) over the period 1961–2005 in an attempt to disentangle the influence of atmospheric variables acting at different times of year.
• Annual growth rings, measured along the north radius of freshly cut (frozen) tree discs and climatological data recorded at an adjacent site were used in the study. Correlations were based on Pearson product–moment correlation coefficients between the annual growth anomaly and these climatic and atmospheric factors.
• Rather weak correlations between these variables and growth were found. However, there was a consistent and statistically significant relationship between growth of the trees and the flux density of galactic cosmic radiation. Moreover, there was an underlying periodicity in growth, with four minima since 1961, resembling the period cycle of galactic cosmic radiation.
• We discuss the hypotheses that might explain this correlation: the tendency of galactic cosmic radiation to produce cloud condensation nuclei, which in turn increases the diffuse component of solar radiation, and thus increases the photosynthesis of the forest canopy.