Isotopes and Tree Rings

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Isotopes and Tree Rings
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Hurricane Convection and Precipitation
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Lawrence, J.R. 1998 Isotopic spikes from
tropical cyclones in surface waters
Opportunities in hydrology and palaeoclimatology.
Chemical Geology 144 153-160.
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Hypothesis Hurricane precipitation results in 18
O-depleted latewood cellulose. Therefore,
hurricane events can be identified by values of
D18O (earlywood latewood) 0.
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Sample Preparation and Analysis
I. Sample thin slivers (50 mm thick) of EW and
LW for each year using razor blade
II. Pine resins removed using ASE with 3
toluene1 alcohol mix at 125 oC and 1500 psi.
III. a-cellulose extraction using acetic acid
/sodium chlorite then NaOH baths, using 70-85 oC
and agitation (methodology of Green 1963
Loader et al., 1997).
10mm
IV. High temperature pyrolysis to CO and CF-IRMS
with Finnigan MAT TC/EA Delta combination.
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1964 Two major hurricanes affected study area
Cleo (TD) and Dora (H 2-3).
Hurricane Cleo 20 Aug. 5 Sept. 1964
Hurricane Dora 28 Aug.-16 Sept. 1964
DEW-LW 3.77
DEW-LW 3.77
Courtesy of http//weather.unisys.com
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1958 Hurricane Helen a category 3 storm 21
Sept. 4 Oct. 1958
DEW-LW 3.17
Courtesy of http//weather.unisys.com
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1992 Hurricane Andrew - a category 4 storm 16-28
August 1992
DEW-LW 2.63
Courtesy of http//weather.unisys.com
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1953 Hurricane Florence results of sub-sampling
del18O 4.99 (o/oo)