The impact of polar stratospheric ozone loss on Southern Hemisphere stratospheric circulation and climate
The impact of polar stratospheric ozone loss on Southern Hemisphere stratospheric circulation and climate
复制标题
DOI：
10.5194/acp-14-13705-2014
复制
发表时间：
2014-12
影响因子：
6.3
通讯作者：
J. Keeble;P. Braesicke;N. Abraham;H. Roscoe;J. Pyle
中科院分区：
文献类型：
--
作者：
J. Keeble;P. Braesicke;N. Abraham;H. Roscoe;J. Pyle
抽象的。使用与完全耦合化学气候模型 UM-UKCA 运行的一对模型集成来检查氯活化对极地平流层云造成的极地平流层臭氧损失的影响。发现通过非均相反应抑制氯活化会产生与当前和臭氧空洞前时期观察到的臭氧差异一致的模拟臭氧差异。统计上显着的南半球高纬度 (SH) 臭氧损失始于 8 月，并在 10 月至 11 月达到峰值，超过 75% 的臭氧在 50 hPa 时被破坏。与臭氧破坏相关的是低极平流层温度下降> 12 K，而上层平流层温度增加> 6 K。诊断了这种温度变化的加热成分，发现温度偶极子是平流层下部短波加热减少和平流层上部动力加热增加的结果。极地低平流层的冷却通过热风平衡导致极地涡旋加速，并将其破坏延迟约两周。平流层低层纬向风速、埃利亚森-帕尔姆 (EP) 通量的垂直分量 Fz 和残余平均垂直环流 w * 之间的联系已被确定。 11 月和 12 月，西风增强和极地涡旋分裂延迟导致 Fz 增加，表明进入平流层并传播到更高海拔的波浪活动增加。由此产生的波浪破碎的增加（通过 EP 通量散度的减小来诊断）推动了极冠上空的下降流增强。本研究中模拟的许多平流层信号向下传播到对流层，并导致 12 月的地表发生显着变化。
Abstract. The impact of polar stratospheric ozone loss resulting from chlorine activation on polar stratospheric clouds is examined using a pair of model integrations run with the fully coupled chemistry climate model UM-UKCA. Suppressing chlorine activation through heterogeneous reactions is found to produce modelled ozone differences consistent with observed ozone differences between the present and pre-ozone hole period. Statistically significant high-latitude Southern Hemisphere (SH) ozone loss begins in August and peaks in October–November, with > 75% of ozone destroyed at 50 hPa. Associated with this ozone destruction is a > 12 K decrease of the lower polar stratospheric temperatures and an increase of > 6 K in the upper stratosphere. The heating components of this temperature change are diagnosed and it is found that the temperature dipole is the result of decreased short-wave heating in the lower stratosphere and increased dynamical heating in the upper stratosphere. The cooling of the polar lower stratosphere leads, through thermal wind balance, to an acceleration of the polar vortex and delays its breakdown by ~ 2 weeks. A link between lower stratospheric zonal wind speed, the vertical component of the Eliassen–Palm (EP) flux, Fz and the residual mean vertical circulation, w *, is identified. In November and December, increased westerly winds and a delay in the breakup of the polar vortex lead to increases in Fz, indicating increased wave activity entering the stratosphere and propagating to higher altitudes. The resulting increase in wave breaking, diagnosed by decreases to the EP flux divergence, drives enhanced downwelling over the polar cap. Many of the stratospheric signals modelled in this study propagate down to the troposphere, and lead to significant surface changes in December.