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jjoensuu
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 Posted: Sun Oct 12, 2008 12:58 pm Post subject: Rain carries a chemical signature that is linked to the amou |
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Hi folks
I wanted to ask a question about something I read from an article at
www.earthsky.org/teachers/article/ancient-rainfall.
The article, titled "Ancient Rainfall", states that:
<snip>
The Israeli scientists have carefully sliced into cave features to
figure out the amount of rain that fell in the past. What they’ve
found matches archaeological records of ancient floods and droughts.
And although recent conditions in the Middle East have been pretty
dry, they’ve been both drier and wetter at various times in the past.
In fact, comparing the rainfall with the region’s archaeology suggests
the ebb and flow of civilizations in the region might be synchronized
with the cycle of rain.
DB These scientists are able to do this work because rain carries a
chemical signature that’s linked to the amount of rain that falls. We
have more details about this link – at today’s show at earthsky.org.
</snip>
The question I wanted to ask is, what is this "chemical signature"
that is linked to the amount of falling rain? A pointer to a website
that explains this would also be appreciated (I looked around on the
earthsky.org but did not find any further information on this).
Thanks in advance, |
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Weatherlawyer
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| Posted: Sun Oct 12, 2008 11:57 pm Post subject: Re: Chemical signature of rain. |
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On Oct 12, 1:58 pm, jjoensuu <j_joen...@yahoo.com> wrote:
[quote]Hi folks
I wanted to ask a question about something I read from an article atwww.earthsky.org/teachers/article/ancient-rainfall.
The article, titled "Ancient Rainfall", states that:
snip
The Israeli scientists have carefully sliced into cave features to
figure out the amount of rain that fell in the past. What they’ve
found matches archaeological records of ancient floods and droughts.
And although recent conditions in the Middle East have been pretty
dry, they’ve been both drier and wetter at various times in the past.
In fact, comparing the rainfall with the region’s archaeology suggests
the ebb and flow of civilizations in the region might be synchronized
with the cycle of rain.
DB These scientists are able to do this work because rain carries a
chemical signature that’s linked to the amount of rain that falls. We
have more details about this link – at today’s show at earthsky.org.
/snip
The question I wanted to ask is, what is this "chemical signature"
that is linked to the amount of falling rain? A pointer to a website
that explains this would also be appreciated (I looked around on the
earthsky.org but did not find any further information on this).
[/quote]
Beats me. It>s not even groundwater by the time it gets to the cave.
(It>s undergroundwater.)
If it didn>t say what it was in the article, it wasn>t that good an
article was it? |
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Martin Brown
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| Posted: Mon Oct 13, 2008 2:44 pm Post subject: Re: Rain carries a chemical signature that is linked to the |
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jjoensuu wrote:
[quote]Hi folks
I wanted to ask a question about something I read from an article at
www.earthsky.org/teachers/article/ancient-rainfall.
The article, titled "Ancient Rainfall", states that:
snip
The Israeli scientists have carefully sliced into cave features to
figure out the amount of rain that fell in the past. What they’ve
found matches archaeological records of ancient floods and droughts.
And although recent conditions in the Middle East have been pretty
dry, they’ve been both drier and wetter at various times in the past.
In fact, comparing the rainfall with the region’s archaeology suggests
the ebb and flow of civilizations in the region might be synchronized
with the cycle of rain.
DB These scientists are able to do this work because rain carries a
chemical signature that’s linked to the amount of rain that falls. We
have more details about this link – at today’s show at earthsky.org.
/snip
The question I wanted to ask is, what is this "chemical signature"
that is linked to the amount of falling rain? A pointer to a website
that explains this would also be appreciated (I looked around on the
earthsky.org but did not find any further information on this).
[/quote]
I think they have slightly misstated it. There are stable isotope ratio
signatures that are characteristic of heavy rain (and also longer term
of the amount of water locked up as ice at the poles). See for example:
http://gsa.confex.com/gsa/2006NC/finalprogram/abstract_103620.htm
and
http://www.iaea.org/programmes/ripc/ih/volumes/vol_two/ChT_II_04.pdf
It goes back quite a way. The same technique can also be used to
determine if sugars used in wine really came from grapes.
Regards,
Martin Brown
** Posted from http://www.teranews.com ** |
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Weatherlawyer
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| Posted: Tue Oct 14, 2008 9:02 pm Post subject: Re: Rain carries a chemical signature that is linked to the |
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On Oct 13, 10:44 am, Martin Brown <|||newspam...@nezumi.demon.co.uk>
[quote]
I think they have slightly misstated it. There are stable isotope ratio
signatures that are characteristic of heavy rain (and also longer term
of the amount of water locked up as ice at the poles).
See for example:
http://gsa.confex.com/gsa/2006NC/finalprogram/abstract_103620.htm
andhttp://www.iaea.org/programmes/ripc/ih/volumes/vol_two/ChT_II_04.pdf
It goes back quite a way. The same technique can also be used to
determine if sugars used in wine really came from grapes.
[/quote]
From the abstract:
"The Evansville, Indiana region typically receives a portion of its
annual precipitation from moisture originating in the Gulf of Mexico.
However, during 2005, just four individual hurricanes (Arlene, Dennis,
Katrina, and Rita) delivered an anomalously high proportion of local
summer rainfall (24.2 cm of 43.4 cm from June through September, 56%).
Rain from these four hurricanes delivered approximately 23% of the
local annual precipitation for 2005.
We hypothesize that the precipitation from these storms will contain a
distinctively heavier 18O/16O and 2H (Deuterium) signature than
“normal” summer rainfall, and therefore might prove useful as an
environmental tracer.
Isotopic analyses of eighteen water samples included three rain
samples from two hurricanes (Katrina and Rita), four “typical”
rainfall events and two snow samples.
Additionally nine bedrock ground water samples were collected from a
deep – shallow piezometer nest in the Inglefield Sandstone located on
the University of Southern Indiana campus.
Stable isotopic ratios of precipitation yielded a meteoric water line
specific to the Evansville, Indiana region.
Some sampled hurricane precipitation has a distinctive, heavier
isotopic signature,
Isotopic ratios of snow “anchor” the light extreme of sampled meteoric
water.
Stable isotope ratios of both deep and shallow ground water generally
fall on the local meteoric line.
Deep ground water consistently displays slightly lighter ratios than
shallow ground water.
Given that 2005 hurricane rainfall appears to be isotopically and
volumetrically distinct, it may assist in characterizing the local
ground water flow system, and recharge to, the Inglefield Sandstone
aquifer.
Sampling and analyses for isotopic ratios is ongoing."
It would be nice if whoever sets the baseline for doctorate papers
gets to institute paragraph spacings if not big words and loser
phraseology.
Be that as it may, it isn>t that hard to translate it into English
that even United States of Americans can understand.
I take it the body of the text explains why and how the different
water sources have different atomic composition?
I>d have thought it bloody obvious that when more and larger
hurricanes hit a region then the water samples in that area are going
to reflect that. But the abstract stated the usual source of moisture
is the Gulf. So what is the difference?
I thought the hurricanes were from the gulf? |
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