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Re: Re: Re: Not sure about this one..... |
| Name: |
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Dave Gardner |
| Date Posted: |
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Mar 6, 06 - 10:53 PM |
| Email: |
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djgardner@btinternet.com |
| Instant Messenger: |
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http://,1 |
| Message: |
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I think this link may help:
http://www.agu.org/sci_soc/mockler.html
"The weight of the atmosphere's water vapor contributes only about one quarter of one percent of the total sea level pressure of all the gases. If all the water vapor in the air at a particular time were to condense and fall as rain, it would amount to a depth of only about 2.5 cm. This is called precipitable water. Because water vapor is not evenly distributed globally, there would be about 5 cm near the equator and less than one tenth as much at the poles. The average precipitation over the globe is about 1 m annually, so there must be a rapid turnover of water in the air; the average water molecule spends about 9 days in the air before precipitating back to the surface."
So the atmospheric water vapour concentration at the poles is less than a tenth what it is at the equator. From Figure 2 of the above link, which gives the precipitable water vapour column heights in 1992, it looks like the North Pole is 4-8 mm and the South Pole is 0-4 mm compared with an equator maximum of 50-60 mm.
But although the satellite temperatures seem to be seeing an increase in temperature near the poles, and it is being attributed in the pdf report to the higher CO2 to water vapour ratio in cold, dry air, surface temperature measurements seem to contradict this and show a decrease.
According to this BBC news story, Greenland, which is pretty near the North pole, has reduced in average surface temperature by 1.29 deg C from 1958 to 2001: http://news.bbc.co.uk/1/hi/sci/tech/2840137.stm
And at the South pole the surface temperature seems to be going down as well:
http://www.john-daly.com/stations/amundsen.gif (this is from the john-daly.com website, the "what the stations say" link) |
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