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皮纳图博火山喷发物在南极点雪层内的记录及其意义 总被引:3,自引:0,他引:3
1991年6月菲律宾皮纳图博火山喷发,导致大气圈火山灰气溶胶含量激增,连同1991年8月智利哈德森火山喷发释放的火山灰一道,导致自1991年12月起南极点降水中SO^2-4开始增加,激光雷达同时也观测到富含火山微尘气团的到达。雪样中火山微粒的电镜分析结果,以及据物质平衡观测值估算的年代等表明,1994年12月在南极点0.1-0.9m雪层中可钭2次火山喷发事件区别开采、估算出南极点处皮纳图博火山和哈 相似文献
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Ninglian Wang Tandong Yao Dahe Qin L. G. Thompson E. Mosley-Thompson J. Cole-Dai M. E. Davis P. -N. Lin 《科学通报(英文版)》1999,44(17):1616-1616
A36Cl peak was found in the predicted section of Guliya ice core, from the Qinghai-Tibetan Plateau, at about 37 kaBP. This cannot
be interpreted by means of changes in the accumulation rate, but by the enhanced cosmogenic isotope production rate in the
atmosphere. Compared with the records of10Be and36Cl in the other regions, the peaks of the cosmogenic isotopes are global and can be considered as time marks. An intriguing
fact is that the peaks coincided with cold periods. 相似文献
3.
McConnell JR Arthern RJ Mosley-Thompson E Davis CH Bales RC Thomas R Burkhart JF Kyne JD 《Nature》2000,406(6798):877-879
The response of grounded ice sheets to a changing climate critically influences possible future changes in sea level. Recent satellite surveys over southern Greenland show little overall elevation change at higher elevations, but large spatial variability. Using satellite studies alone, it is not possible to determine the geophysical processes responsible for the observed elevation changes and to decide if recent rates of change exceed the natural variability. Here we derive changes in ice-sheet elevation in southern Greenland, for the years 1978-88, using a physically based model of firn densification and records of annual snow accumulation reconstructed from 12 ice cores at high elevation. Our patterns of accumulation-driven elevation change agree closely with contemporaneous satellite measurements of ice-sheet elevation change, and we therefore attribute the changes observed in 1978-88 to variability in snow accumulation. Similar analyses of longer ice-core records show that in this decade the Greenland ice sheet exhibited typical variability at high elevations, well within the long-term natural variability. Our results indicate that a better understanding of ice-sheet mass changes will require long-term measurements of both surface elevation and snow accumulation. 相似文献
4.
Traces of tephra and increased sulfate (SO
4
2−
) concentrations were identified in the 1992–1994 snow layers in 2 firn cores from South Pole. The deposition of the Pinatubo
SO
4
2−
aerosol was delayed due to the long transport to the high south latitudes and its initial existence at high altitudes in
the Antarctic atmosphere. Electron microscopic analyses show that the element composition of the tephra is identical to that
of volcanic ash found near the Pinatubo volcano in Philippines. Detailed stratigraphic snow sampling resolved the Pinatubo
signal from that of Cerro Hudson eruption during August 1991 in Chile. The South Pole sulfate flux from Pinatubo is calculated
to be (10.9±1.1) kg·km−2, while the Hudson sulfate flux is (3.2±1.1) kg·km−2. This information will be useful to estimating the magnitudes of the past volcanic eruptions recorded in Antarctic ice core. 相似文献
5.
≈37 kaBP大气中宇宙成因同位素含量增加的古里雅冰芯证据 总被引:3,自引:1,他引:3
证实了≈37kaBP青藏高原古里雅冰芯记录中这于宙成因同位素^36Cl含量峰值的存在,并认为该峰值是^36Cl在大气中产生速率增加导致的,而不是净积累速率变化影响的结果。发现这一峰值事件与气候变冷相伴出现。 相似文献
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