High-Resolution Ice Cores from US ITASE (West Antarctica): Development and Validation of Chronologies and Determination of Precision and Accuracy

Shallow ice cores were obtained from widely distributed sites across the West Antarctic ice sheet, as part of the United States portion of the International Trans-Antarctic Scientific Expedition (US ITASE) program. The US ITASE cores have been dated by annual-layer counting, primarily through the identification of summer peaks in non-sea-salt sulfate (nssSO(4)(2-)) concentration. Absolute dating accuracy of better than 2 years and relative dating accuracy better than 1 year is demonstrated by the identification of multiple volcanic marker horizons in each of the cores, Tambora, Indonesia (1815), being the most prominent. Independent validation is provided by the tracing of isochronal layers from site to site using high-frequency ice-penetrating radar observations, and by the timing of mid-winter warming events in stable-isotope ratios, which demonstrate significantly better than 1 year accuracy in the last 20 years. Dating precision to 1 month is demonstrated by the occurrence of summer nitrate peaks and stable-isotope ratios in phase with nssSO(4)(2-), and winter-time sea-salt peaks out of phase, with phase variation of \u3c 1 month. Dating precision and accuracy are uniform with depth, for at least the last 100 years

RELATIONSHIPS AMONG STRATEGIC COMMODITIES AND WITH FINANCIAL VARIABLES: A NEW LOOK

"We examine the comovements among the prices of four strategic commodities that have long, adequate daily series: oil, gold, silver, and copper as a group. We also explore their causal relationships with two commodity-relevant macrofinancial variables: interest and exchange rates as an expanded group to shed some light on the prediction behaviors of those individual commodity prices relative to the selected financial variables. In the expanded group, the selected interest rate can provide a transmission link between commodity prices and the dollar exchange rate. The results and their policy implications are discussed at length". ("JEL "C51, E27, Q43) Copyright (c) 2008 Western Economic Association International.