Sentences with phrase «centuries of air bubbles»

Not exact matches

There is contamination of the air in the bubble by water; different results are obtained if the ice is crushed or melted to obtain the air sample; it takes decades for the air bubble to form; the raw data was smoothed out by a 70 year moving average that removed the great annual variability found in the 19th century and Stomata Index (SI) records; closer examination revealed a major flaw in the hypothesis because temperature rises before CO2.

B) For the ice cores the progressive closing of the diffusion paths between the surface and the «air bubbles» of a layer of the firn is tantamount to a temporal low - pass filter which smoothes the transitions faster than several centuries (in Antarctica where the precipitation of ice is a few mm / year, it's the time it takes for some 50 m of water to accumulate).

[71][72] Because of the way air is trapped in ice (pores in the ice close off slowly to form bubbles deep within the firn) and the time period represented in each ice sample analyzed, these figures represent averages of atmospheric concentrations of up to a few centuries rather than annual or decadal levels.