A Model Study of the Impact of Volcanic Eruptions on Polar Ozone Depletion.

火山喷发产生的气体和气溶胶会改变高层大气的臭氧化学和能量平衡。这项研究将调查过去的火山喷发如何影响极地平流层云和平流层臭氧。该项目还将比较较小的、持续的火山排放的影响与大规模喷发的影响。大气化学、动力学和辐射的计算机模型将被用来检查过去喷发的影响，以及它们可能如何减缓臭氧层空洞的恢复。这项研究还将通过纳入更真实的极地平流层云来改进模型，这将提高我们模拟大气化学并最终模拟气候的能力。这项研究将研究受火山喷发影响的极地平流层云(PSCs)的演变及其对臭氧和相关化学物质的影响。观察到火山气溶胶改变了平流层的辐射通量和化学成分。臭氧探空仪和卫星观测显示，在皮诺博先生、塞罗哈德森和厄尔奇雄事件之后，中纬度地区和南极洲上空的臭氧损失加剧。一个悬而未决的问题是，每年都会发生微小的破坏，但在大规模喷发时只会注入一小部分硫，如何影响极地地区的臭氧损失并减缓臭氧空洞的恢复。这项研究将使用NSF/NCAR全大气社区气候模式(WACCM)和社区大气气溶胶和辐射模式(CARMA)，前者包含详细的臭氧化学，后者包含一个相互作用的硫酸盐和PSCS模式。模型实验将向大气中注入不同数量、不同时间和不同地点的二氧化硫，以模拟过去几十年观察到的火山喷发。结果将与卫星和现场观测结果进行比较，从微观物理尺度到全球尺度。该项目的另一个目标是通过更现实地对待PSC来改进NSF/NCAR WACCM模型。该项目有助于理解硫酸盐和尘埃在冰芯中的沉积如何与喷发的地点和强度有关，有助于理解由小喷发引起的南极臭氧损失的年复一年变化，以及理解PSC和火山气溶胶对南极能量平衡的影响。

Gases and aerosols from volcanic eruptions cause changes in the ozone chemistry and energy balance of the upper atmosphere. This study will investigate the how past volcanic eruptions have influenced polar stratospheric clouds and stratospheric ozone. The project will also compare the effect of smaller, sustained volcanic emissions to the effect of large eruptions. A computer model of atmospheric chemistry, dynamics, and radiation will be used to examine the impact of past eruptions and how they may slow down the recovery of the ozone hole. This study will also improve the models by including more realistic polar stratospheric clouds, which will improve our ability to model atmospheric chemistry, and ultimately, climate.This study will investigate the evolution of polar stratospheric clouds (PSCs) influenced by volcanic eruptions and the resulting effect on ozone and related chemicals. Volcanic aerosols are observed to change stratospheric radiative flux and chemistry. Ozonesonde and satellite observations show enhanced ozone loss in the mid-latitudes and over Antarctica following the Mr. Pinaubo, Cerro Hudson, and El Chichon erruptions. An unanswered question is how small erruptions which occur every year but only inject a small fraction of the sulfur as a large eruption impact the ozone loss in polar regions and slow down the recovery of the ozone hole. This study will use the NSF/NCAR Whole Atmosphere Community Climate Model (WACCM) with detailed ozone chemistry and the Community Aerosol and Radiation Model for Atmospheres (CARMA) with an interactive sulfate and PSCs model. The model experiments will inject SO2 into the atmosphere in different amounts, times, and locations to simulate the volcanic eruptions observed during the past few decades. The results will be compared to satellite and in-situ observations from microphysical scales to global scales. Another goal of the project is to improve the NSF/NCAR WACCM model by treating PSCs more realistically. The project is relevant to understanding how the deposition of sulfates and dust in ice cores relates to the locations and strength of eruptions, to understanding year-to-year variations in Antarctic ozone loss driven by small eruptions, and to understanding the effect of PSCs and volcanic aerosols on the Antarctic energy balance.