Three-dimensional radiocarbon modeling: A tool to assess the last glacial ocean circulation and radiocarbon chronologies

Abstract

PAGES News • Vol.16 • No 2 • April 2008 Sp ec ia l S ec tio n: D at aM od el C om pa ri so n during the LIA. Again, these changes can be attributed to shifts of the SHWs. Additionally, lacustrine investigations (Haberzettl, 2006; Stine and Stine, 1990) indicate lower temperatures and wetter conditions in Patagonia during the LIA. Pollen-based results point to vegetation-type changes from dry to wet species. The latter can also be attributed to shifts in the SHWs (Mayr et al., 2007). Further, the analysis of glaciers and moraines in Patagonia show extensive glaciation during the LIA (Harrison et al., 2006, Koch and Kilian, 2005, Thompson et al., 1986). Therefore, the comparison between proxy-based reconstructions and results from the GCM simulation show that both, model and proxy data indicate a climatically anomalous period between the mid16th and 19th century over southern South America. This suppors the hypothesis that the LIA, as indicated in proxy based and modeled northern hemispheric temperatures, is also reflected in hydrological variables over parts of the southern hemisphere. References Harrison, S., Glasser, N., Winchester, V., Haresign, E., Warren, C. and Jansson, K., 2006: A glacial lake outburst flood associated with recent mountain glacier retreat, Patagonian Andes, The Holocene, 16(4): 611-620. Lara, A. and Villalba, R., 1993: A 3620-Year Temperature Record From Fitzroya cupressoides Tree Ring in Southern South America, Science, 260: 104-1106. Mayr, C. et al., 2007: Holocene variability of the Southern Hemisphere westerlies in Argentiniean Patagonia (52°S), Quaternary Science Reviews, 26: 579-584. von Storch, H., Zorita, E., Jones, J., Dimitriev, Y., Gonzalez-Rouco, F. and Tett, S., 2004: Reconstructing past climate from noisy data, Science, 306: 679-682. Wagner, S., Widmann, M., Jones, J., Haberzettl, T., Lucke, A., Mayr, C., Ohlendorf, C., Schabitz, F. and Zolitschka, B., 2007: Transient simulations, empirical reconstructions and forcing mechanisms for the Mid-Holocene hydrological climate in Southern Patagonia, Climate Dynamics, 29: 333-355.