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

During the Sino-American Expedition to Mt. Qomolangma (Mt. Everest) in May 1997, a 41 in ice core was recovered from an elevation of 6500 in from the northern branch firn basin of the Far East Rongbuk (FER) Glacier near Mt. Q omolangma (Mt. Everest). The ice core was dated down to AD 1814 by counting (delta O-18 and major ion peaks calibrated to P activity bomb lavers. The average annual accumulation is 224 min (ice equivalent). Five cold periods and five warm periods have been reconstructed from the FE R ice core records for the last 200 years and the general tendency of clima tic change is warming, which agrees with recent temperature change in the N orthern Hemisphere. The climatic records from the FER ice core agree with t hose from the Guliya ice core, suggesting that the climatic changes are con sistent over the Qinghai-Tibetan Plateau, especially for the plateau-wide 2 0th-century warming trend. Over the last 200 years, eight intense dust periods and nine lesser dust pe riods are recorded in the FER ice core, The more intense dust periods are d uring the 1830s to 1840s, and in 1880s and 1960s. The longest low dust peri od lasted from the 1890s to 1920s. Several maxima in crustal ion concentrat ions are consistent with strong dust storms recorded in the historical docu ment from northwestern China. At the beginning of 20th century, C2O42- conc entration from industrial source started to increase, notably during 1950s to 1980s.