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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >STRATOSPHERIC LOADING AND OPTICAL DEPTH ESTIMATES OF EXPLOSIVE VOLCANISM OVER THE LAST 2100 YEARS DERIVED FROM THE GREENLAND ICE SHEET PROJECT 2 ICE CORE
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STRATOSPHERIC LOADING AND OPTICAL DEPTH ESTIMATES OF EXPLOSIVE VOLCANISM OVER THE LAST 2100 YEARS DERIVED FROM THE GREENLAND ICE SHEET PROJECT 2 ICE CORE

机译：从格陵兰岛冰板项目2的冰芯推导的最近2100年的爆发性火山活动的平流层负荷和光学深度估计

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The high-resolution and lengthy records of volcanic aerosol deposition in ice cores allow assessment of the atmospheric impact of different styles and magnitudes of past eruptions and the impact of volcanism during periods of varied climatic conditions. The 2100-year long volcanic SO42- time series in the Greenland Ice Sheet Project 2 (GISP2) ice core was used to calculate the mass stratospheric loading (M(D)) of H2SO4 and resulting optical depth values (tau(D) = M(D)/1.5 x 10(14) g) for individual, and multiple, closely spaced eruptions. Calibration of the calculated optical depth values with other compilations spanning the last 150 years provides a range of values for each eruption or set of eruptions essential to quantifying the climate forcing capabilities of each of these events. Limitations on the use of the results exist because this is only a single ice core, sampling was biannual and transport, and deposition of aerosols is not consistent among individual eruptions. The record of volcanic optical depth estimates is characterized by distinct trends within three consecutive 700-year time periods. The period from 100 B.C. to A.D. 600 is characterized by the fewest eruptions, and optical depth values are lower than those in the rest of the record. The exception is an extremely large signal of 3 years duration that is probably associated with an unknown Icelandic eruption around 53 B.C., with the possible contribution of another high-latitude eruption. The presence of another signal at 43 B.C. suggests that at least two eruptions impacted climate in the middle decade of the Ist century B.C. The period from A.D. 600 to 1300 has intermediate numbers and magnitudes of volcanic events except for the very large 1259 event. Stratospheric loading and optical depths values for the 1259 event are twice that for Tambora (A.D. 1815). The state of the climate system in the middle of the thirteenth century A.D. may not have been sensitive enough to the atmospheric perturbation of the 1259 eruption, thus the apparent lack of abundant proxy evidence of climatic cooling around A.D. 1260. The most recent 700 years (A.D. 1400-1985) are characterized by the greatest number of eruptions (half of those recorded over the 2100 years of record) and, in general, the highest stratospheric loading and optical depth values for individual and the combined effects of multiple eruptions. The large Kuwae eruption (A.D. 1450s) may have perturbed the atmosphere at least as much as Krakatau and possibly of a magnitude similar to Tambora Multiple eruptions in the 50-to 60-year periods from A.D. 1580s-1640s and A.D. 1780s-1830s may have had a significant impact on enhancing the already cool climatic conditions in those time periods, particularly around A.D. 1601 and 1641. These findings imply that multiple eruptions closely spaced in time are more likely to have a major impact on a decadal time scale when existing climatic conditions are in a more sensitive or transitional state. The GISP2 ice core record also indicates that several relatively unknown eruptions may have been large sulfur producers during the 17th and 19th centuries A.D., thereby warranting further studies of those particular events. [References: 82]
机译：高分辨率和冗长的火山岩气溶胶在冰芯中的沉积记录，可以评估不同样式和大小的过去喷发对大气的影响，以及在气候条件变化时期火山活动的影响。格陵兰冰原项目2（GISP2）冰芯中具有2100年长的火山SO42-时间序列用于计算H2SO4的平流层质量负荷（M（D））和所得的光学深度值（tau（D）= M （D）/1.5 x 10（14）g）适用于单个和多个紧密间隔的喷发。过去150年中使用其他汇编对计算的光学深度值进行的校准，为每一次喷发或一次喷发提供了一系列数值，这些数值对于量化这些事件的气候强迫能力至关重要。存在使用结果的限制，因为这只是单个冰芯，采样是半年一次的并且是运输的，并且每次爆发之间气溶胶的沉积不一致。火山光学深度估计的记录的特征在于连续三个700年时间段内的明显趋势。从公元前100年开始到公元600年的特征是喷发最少，并且光学深度值低于记录的其余部分。例外是持续时间为3年的巨大信号，可能与公元前53年左右的一次未知冰岛喷发有关，可能与另一次高纬度喷发有关。在公元前43年出现另一个信号表明在公元前一世纪中叶至少有两次喷发影响了气候。从公元600年到1300年这段时期，除了非常大的1259事件外，具有中等数量的火山事件。 1259年事件的平流层载荷和光学深度值是Tambora（公元1815年）的两倍。公元13世纪中叶的气候系统状态可能对1259年喷发的大气扰动不够敏感，因此，显然缺乏充足的代理证据来证明公元1260年左右的气候降温。最近700年（ AD 1400-1985年）的特征是喷发数量最多（在2100年的记录中有一半为喷发），并且一般来说，对于单个喷发和多次喷发的综合影响，平流层负荷和光学深度值最高。大型库瓦火山喷发（公元1450年代）可能至少扰乱了Krakatau的大气，其强度可能与公元1580年代至1640年代和公元1780年代至1830年代的50至60年间的坦波拉多次喷发相似。对改善当时已经凉爽的气候条件具有重大影响，尤其是在公元1601年和1641年左右。这些发现表明，在现有气候条件下，时间间隔很近的多次喷发对年代际尺度更可能产生重大影响处于更敏感或过渡的状态。 GISP2的冰芯记录还表明，在公元17世纪和19世纪期间，有几次相对未知的喷发可能是大型的硫磺产生者，因此有必要对这些特殊事件进行进一步的研究。 [参考：82]

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