On the impact of future climate change on tropopause folds and tropospheric ozone
On the impact of future climate change on tropopause folds and tropospheric ozone
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DOI：
10.5194/acp-19-14387-2019
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发表时间：
2019-11-28
影响因子：
6.3
通讯作者：
Zanis, Prodromos
中科院分区：
文献类型：
--
作者：
Akritidis, Dimitris;Pozzer, Andrea;Zanis, Prodromos
使用瞬态模拟1960 - 2100年期间与国家的最先进的ECHAM 5/MESSy大气化学（EMAC）的全球模式和对流层顶褶皱识别算法，我们探索未来预计的对流层顶褶皱，平流层到对流层的臭氧传输（STT），对流层臭氧的RCP6.0情景下的变化。从1970-1999年到2070-2099年，在两个半球的对流层顶折叠频率的统计显着变化，区域超过3%，并与副热带急流的位置和强度的预测变化。预计未来两个半球的臭氧短时温度都将加强，整个对流层的平流层臭氧示踪剂传输量将相应增加，对流层上层将达到10 nmol mol（-1），对流层中层将达到8 nmol mol（-1），近地表将达到3 nmol mol（-1）。值得注意的是，在400百帕臭氧STT的变化最大的区域与那些具有最高的折叠频率变化相吻合，突出了对流层顶折叠机制在气候变化下STT过程中的作用。对于东地中海和中东（EMME）和阿富汗（AFG）地区，这是众所周知的热点折叠活动和臭氧STT在夏季期间，平流层起源的对流层中层臭氧的年与年的变化主要是由臭氧在150百帕和对流层顶折叠频率的短期变化来解释。最后，在RCP6.0情景下，预计在MAM期间对流层低层的臭氧将减少（3月、4月和5月）和JJA（6月、7月和8月）在北方半球和DJF期间（12月、1月和2月），由于臭氧前体排放量减少以及水蒸气丰度增加导致臭氧损失增加，而对流层其它区域的臭氧则显著增加，这主要是由于STT的加强和平流层臭氧的恢复。
Using a transient simulation for the period 19602100 with the state-of-the-art ECHAM5/MESSy Atmospheric Chemistry (EMAC) global model and a tropopause fold identification algorithm, we explore the future projected changes in tropopause folds, stratosphere-to-troposphere transport (STT) of ozone, and tropospheric ozone under the RCP6.0 scenario. Statistically significant changes in tropopause fold frequencies from 1970-1999 to 2070-2099 are identified in both hemispheres, regionally exceeding 3 %, and are associated with the projected changes in the position and intensity of the subtropical jet streams. A strengthening of ozone STT is projected for the future in both hemispheres, with an induced increase in transported stratospheric ozone tracer throughout the whole troposphere, reaching up to 10 nmol mol(-1) in the upper troposphere, 8 nmol mol(-1) in the middle troposphere, and 3 nmol mol(-1) near the surface. Notably, the regions exhibiting the largest changes of ozone STT at 400 hPa coincide with those with the highest fold frequency changes, highlighting the role of the tropopause folding mechanism in STT processes under a changing climate. For both the eastern Mediterranean and Middle East (EMME) and Afghanistan (AFG) regions, which are known as hotspots of fold activity and ozone STT during the summer period, the year-to-year variability of middle-tropospheric ozone with stratospheric origin is largely explained by the short-term variations in ozone at 150 hPa and tropopause fold frequency. Finally, ozone in the lower troposphere is projected to decrease under the RCP6.0 scenario during MAM (March, April, and May) and JJA (June, July, and August) in the Northern Hemisphere and during DJF (December, January, and February) in the Southern Hemisphere, due to the decline of ozone precursor emissions and the enhanced ozone loss from higher water vapour abundances, while in the rest of the troposphere ozone shows a remarkable increase owing mainly to the STT strengthening and the stratospheric ozone recovery.