Climatic and environmental records from the Far East Rongbuk ice core, Mt. Qomolangma (Mt. Everest)

Abstract

During the Sino-American Expedition to Mt. Qomolangma (Mt. Everest) in May 1997, a 41 m ice core was recovered from an elevation of 6500 m from the northern branch firn basin of the Far East Rongbuk (FER) Glacier near Mt. Qomolangma (Mt. Everest). The ice core was dated down to AD 1814 by counting δ18O and major ion peaks calibrated to β activity bomb layers. The average annual accumulation is 224 mm (ice equivalent). Five cold periods and five warm periods have been reconstructed from the FER ice core records for the last 200 years and the general tendency of climatic change is warming, which agrees with recent temperature change in the Northern Hemisphere. The climatic records from the FER ice core agree with those from the Guliya ice core, suggesting that the climatic changes are consistent over the Qinghai-Tibetan Plateau, especially for the plateau-wide 20th-century warming trend. Over the last 200 years, eight intense dust periods and nine lesser dust periods are recorded in the FER ice core. The more intense dust periods are during the 1830s to 1840s, and in 1880s and 1960s. The longest low dust period lasted from the 1890s to 1920s. Several maxima in crustal ion concentrations are consistent with strong dust storms recorded in the historical document from northwestern China. At the beginning of 20th century, C2O42- concentration from industrial source started to increase, notably during 1950s to 1980s.