Ice core climate signals recorded in dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the Kamchatka-Peninsula (15001997) and short chain low molecular weight fatty acids from the Alaskan Aurora Peak (17342008)

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Monday, 5 January 2015
Ambarish Pokhrel, Hokkaido University, Sapporo, Hokkaido, Japan; and K. Kawamura, O. Seki, T. Shiraiwa, and S. Matoba

An ice core (212 m deep, 489 years old) was drilled at an ice cap of the Kamchatka-Peninsula, Russia (5604'N, 16028'E, Elevation: 3,903 m). 122 ice core sections were analyzed for homologous series of normal and branched saturated, unsaturated and multifunctional dicarboxylic acids, w-oxocarboxylic acids, pyruvic acid and a-dicarbonyls using a gas chromatography (GC; HP 6890) and GC/MS. We found the predominance of oxalic (C2), followed by succinic (C4) and malonic (C3) acid. Molecular distribution of w-oxocarboxylic acids is characterized by the predominance of glyoxylic (ωC2) followed by 9-oxononanoic (ωC9) and 8-oxooctanoic (ωC8) acid. These molecular distributions are different than those found in the Greenland Site-J and Alaskan Aurora Peak ice cores. Concentrations of these species are fluctuated in similar ways to each other with maxima in 1725-1775, 1825-1875 and 1950s-1990s. Lower spikes are well correlated with the reconstructed Maunder, Dalton and Damon and/or Gleissberg minima of solar irradiance, suggesting that organic compounds were strongly associated with past oxidizing capacity of the lower troposphere. Hydrogen isotope (dD) records reported in the same ice core have followed the Greenland temperature anomaly (GTA), which reflects Arctic Oscillations (AO), North Pacific Gyre Oscillation (NPGO) and/or Pacific/North American climate sensitivity (PNA) and Pacific Decadal Oscillation (PDO). We found a predominance of palmitic (C16:0) followed by oleic (C18:1) and myristic (C14:0) acid in the Aurora Peak ice core from Alaska (63.52N; 146.54W, elevation: 2,825 m), since 1734 to 2008. Alaskan ice core also followed the historical dD records obtained for the Kamchatka ice core that have some links to the sea and air interaction. The Alaskan ice core could be strongly influenced with large-scale climate changes in the North Pacific. Thus, the North Pacific rim ice cores are indicative of the variation in the decadal climate change in the Northern Hemisphere. However, there is a discrepancy between diacids in Kamchatka ice core and fatty acids in Alaskan ice core in terms of decadal to multidecadal climatic forcing, suggesting that two ice core records represent different climate factors in the North Pacific rim. (Words: 337)