Transport of the 2017 Canadian wildfire plume to the tropics via the Asian monsoon circulation
Transport of the 2017 Canadian wildfire plume to the tropics via the Asian monsoon circulation
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DOI：
10.5194/acp-19-13547-2019
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发表时间：
2019-11
影响因子：
6.3
通讯作者：
C. Kloss;G. Berthet;P. Sellitto;F. Ploeger;S. Bucci;S. Khaykin;F. Jégou;G. Taha;L. Thomason
中科院分区：
文献类型：
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作者：
C. Kloss;G. Berthet;P. Sellitto;F. Ploeger;S. Bucci;S. Khaykin;F. Jégou;G. Taha;L. Thomason
抽象的。我们发现，在2017年8月加拿大野火事件期间，注入北部高纬度平流层低层的火羽部分到达热带地区。向热带的输送是由亚洲季风环流的反气旋流动所调节的。火羽于8月下旬/9月初抵达亚洲季风区，当时亚洲季风反气旋(AMA)仍在。虽然没有证据表明混合进入AMA中心，但我们发现很大一部分火羽夹带到AMA边缘的反气旋气流中，并从温带输送到热带地区，特别是南半球，特别是在AMA东侧的南北气流之后。在热带地区，∼在7个月内将火羽抬高5公里。在AMA内部，我们发现了8月亚洲对流层顶气溶胶层(ALAL)的证据，使背景气溶胶条件增加了一倍，计算出的大气顶部短波辐射强迫为−0.05W m−2。9月亚洲季风区更广泛的火灾信号对区域气候的影响比ALAL的影响大2-4倍，并与平流性中等火山喷发产生的烟柱的影响相比。这股烟羽在平流层的跨大陆输送到热带地区，以及与之相关的区域气候影响，都表明污染源之间的长期动力相互联系具有重要意义。
Abstract. We show that a fire plume injected into the lower stratosphere at high northern latitudes during the Canadian wildfire event in August 2017 partly reached the tropics. The transport to the tropics was mediated by the anticyclonic flow of the Asian monsoon circulation. The fire plume reached the Asian monsoon area in late August/early September, when the Asian monsoon anticyclone (AMA) was still in place. While there is no evidence of mixing into the center of the AMA, we show that a substantial part of the fire plume is entrained into the anticyclonic flow at the AMA edge and is transported from the extratropics to the tropics, and possibly the Southern Hemisphere particularly following the north–south flow on the eastern side of the AMA. In the tropics the fire plume is lifted by ∼5 km in 7 months. Inside the AMA we find evidence of the Asian tropopause aerosol layer (ATAL) in August, doubling background aerosol conditions with a calculated top of the atmosphere shortwave radiative forcing of −0.05 W m−2. The regional climate impact of the fire signal in the wider Asian monsoon area in September exceeds the impact of the ATAL by a factor of 2–4 and compares to that of a plume coming from an advected moderate volcanic eruption. The stratospheric, trans-continental transport of this plume to the tropics and the related regional climate impact point to the importance of long-range dynamical interconnections of pollution sources.