期刊
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
卷 127, 期 10, 页码 -出版社
AMER GEOPHYSICAL UNION
DOI: 10.1029/2021JD036249
关键词
-
资金
- Los Alamos National Laboratory (LANL) Laboratory Directed Research and Development program
- NRL Base Program
Stratospheric injections of carbonaceous aerosols and combustion gases by extreme wildfires have become increasingly common. Global climate simulations and remote observations reveal the behavior and impact of megafires on the stratosphere. Factors such as smoke burden, injection heights, and black carbon content determine the plume evolution and potential climate impacts. Understanding these processes is essential for assessing the effects of megafires on the Earth system.
Stratospheric injections of carbonaceous aerosols and combustion gases by extreme wildfires have become increasingly common. Recent megafires, particularly large and intense fires, delivered particulate burdens to the lower stratosphere comparable to those of moderate volcanic eruptions. The 2017 Canadian megafire generated four large Pyrocumulonimbi (pyroCbs), injecting up to approximate to 0.3 Tg of smoke in the lower stratosphere. Even more extreme, the 2019/2020 Australian event produced a pyroCb activity resulting in stratospheric smoke intrusions of approximate to 1 Tg. To understand their contrasting behavior, we present global climate simulations of the atmospheric response to these events, applying smoke burdens informed by remote observations. Model outcomes, compared to satellite data of smoke transport, reproduce reasonably well the initial plume rise, at 0.2-0.3 km/day, attaining heights of approximate to 20 km in Canada and above 30 km in Australia. Global dispersal of the plume occurs within about 3 weeks in both cases, consistent with observations. Smoke removal timescales, approximate to 5 months for the Canadian megafire, agree with remote measurements. During the Australian megafire, observations indicate stratospheric injections three times as large, and models predict comparatively longer smoke lifetimes, approximate to 16 months. After the latter event, atmospheric optical depths and radiative cooling achieved values close to those measured following the Pinatubo eruption. Sensitivity tests of model assumptions indicate, in accord with prior studies, that smoke burden, injection heights, and black carbon content can determine plume evolution and possible climate impacts. An empirical relation between peak heights of stratospheric plumes and lifetimes is derived that can help assess megafire impacts on the stratosphere, climate and the Earth system.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据