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Detailed Reference Information |
Henderson, K.A., Thompson, L.G. and Lin, P.-N. (1999). Recording of El Niño in ice core d18O records from Nevado Huascarán, Peru. Journal of Geophysical Research 104: doi: 10.1029/1999JD900966. issn: 0148-0227. |
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The 68-year monthly resolved time series of Δ18O from ice cores retrieved from the glaciated col of Nevado Huascar¿n, Peru (9 ¿S, 77 ¿W, 6050 m) reflects climate variability over Amazonia and the western tropical Atlantic. Over the 25-year period (1968--1993) of midtroposphere observations, the interannual variations in Huascar¿n Δ18O relate closely with the zonal wind variations over tropical South America at the 500 hPa level. Additionally, there is some evidence that the spatial distribution of temperature anomalies in the western tropical Atlantic has influence on the 500 hPa circulation and hence the isotopic fractionation of moisture advected across Amazonia. During El Ni¿o warming, the moisture convergence axis over the Atlantic Ocean is commonly diverted northward, leading to unusual warm and dry conditions over northeast Brazil, and 18O-enriched snowfall at Huascar¿n. This enrichment phase is enhanced when the peak Pacific warming occurs during the first half of the calendar year, coincident with the wet season over Amazonia. Approximately 12 months later, the El Ni¿o demise is affiliated with a reprisal of strong trade wind circulation, and the resultant cool, pluvial environment over Amazonia triggers a reversal to strongly depleted isotope anomalies. ¿ 1999 American Geophysical Union |
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BACKGROUND DATA FILES |
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Abstract |
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Keywords
Geochemistry, Isotopic composition/chemistry, Oceanography, General, Climate and interannual variability, Oceanography, Physical, El Nino, Atmospheric Composition and Structure, Middle atmosphere—composition and chemistry, Hydrology, General or miscellaneous, Meteorology and Atmospheric Dynamics, Climatology |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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