Correcting the record of volcanic stratospheric aerosol impact: Nabro and Sarychev Peak
Correcting the record of volcanic stratospheric aerosol impact: Nabro and Sarychev Peak
复制标题
DOI：
10.1002/2014jd021507
复制
发表时间：
2014-09-16
影响因子：
4.4
通讯作者：
Lewis, J.
中科院分区：
文献类型：
--
作者：
Fromm, M.;Kablick, G., III;Lewis, J.
自2010年以来，发表了几篇论文，揭示了来自光学光谱仪和红外成像系统(OSIRIS)仪器的平流层气溶胶数据与卡萨托奇、Sarychev Peak和纳布罗火山的其他测量和模型模拟之间的差异模式。Osiris的测量显示了两个差异，气溶胶开始/增加的滞后和最大平流层气溶胶光学厚度的低偏差。假设OSIRIS数据的稳健性得出了各种结论，其中一些有争议，例如认为2011年6月的纳布罗羽流是严格意义上的对流层，并通过亚洲季风间接进入平流层。这些结论是由OSIRIS数据和史密森学会关于严格对流层注入高度的报告得出的。我们讨论了纳布罗喷发的年代学和喷射高度的问题，以及OSIRIS气溶胶差异的原因。我们利用地球静止图像资料绘制了纳布罗喷发高度的时间线，并利用二氧化硫和硫酸盐气溶胶数据反演了喷发开始后平流层羽流的演化。观测表明，纳布罗在2011年6月12日和6月16日首次喷发时，将硫直接注入对流层顶或上方。接下来，对OSIRIS的数据进行非火山和火山扰动条件的检查。在非火山条件下，OSIRIS剖面系统地终止于对流层顶上方1-4公里处。此外，当750nm气溶胶消光超过类似于0.0025公里(-1)时，OSIRIS剖面终止，这一水平通常是在火山注入后超过的。我们的发现在很大程度上解决了已发表的涉及OSIRIS气溶胶数据的工作中的差异，并提供了对纳布罗喷发高度和喷发年代学的修正。
Since 2010, several papers have been published that reveal a pattern of discrepancies between stratospheric aerosol data from the Optical Spectrograph and Infrared Imaging System (OSIRIS) instrument and other measurements and model simulations of volcanic plumes from Kasatochi, Sarychev Peak, and Nabro volcanoes. OSIRIS measurements show two discrepancies, a posteruption lag in aerosol onset/increase and a low bias in maximum stratospheric aerosol optical depth. Assumed robustness of the OSIRIS data drove various conclusions, some controversial, such as the contention that the June 2011 Nabro plume was strictly tropospheric, and entered the stratosphere indirectly via the Asian monsoon. Those conclusions were driven by OSIRIS data and a Smithsonian Institution report of strictly tropospheric injection heights. We address the issue of Nabro's eruption chronology and injection height, and the reasons for the OSIRIS aerosol discrepancies. We lay out the time line of Nabro injection height with geostationary image data, and stratospheric plume evolution after eruption onset using retrievals of sulfur dioxide and sulfate aerosol. The observations show that Nabro injected sulfur directly to or above the tropopause upon the initial eruption on 12/13 June and again on 16 June 2011. Next, OSIRIS data are examined for nonvolcanic and volcanically perturbed conditions. In nonvolcanic conditions OSIRIS profiles systematically terminate 1-4 km above the tropopause. Additionally, OSIRIS profiles terminate when 750 nm aerosol extinction exceeds similar to 0.0025 km(-1), a level that is commonly exceeded after volcanic injections. Our findings largely resolve the discrepancies in published works involving OSIRIS aerosol data and offer a correction to the Nabro injection-height and eruption chronology.