汤加火山喷发SO2全球传输扩散态势模拟研究

针对2022年1月汤加火山喷发SO₂全球扩散态势,采用拉格朗日粒子扩散模式(FLEXPART),基于卫星监测信息对SO₂源项进行评估和设计,在此基础上开展数值模拟(截至2022年2月20日).结果表明,火山喷发初期模式对SO₂南北扩散范围模拟偏窄,但随着时间演变与观测呈现逐渐吻合趋势;SO₂主体位于南半球,向西传输区域主要位于0～30°S纬度带,最大传输速度约22.5°/d,在研究时段跨赤道传输作用弱,对北半球和我国影响小;SO₂在西向传输过程中总体保持前高后低倾斜态势,传输最快高度和向上扩散最大高度分别位于27km和31km左右;截至2月20日,SO₂累积地面沉降已扩展至60°N以南全球大部分区域,主要区域位于0～50°S纬度带,沉降最强地区位于澳大利亚东部、汤加火山西北部和南美洲南部.研究结果可为汤加火山气候效应评估提供数据支撑和思路借鉴.

Simulation study on global diffusional transmission of SO2 from Tonga volcano eruption

The Lagrangian particle diffusion model FLEXPART (FLEXible PARTicle dispersion model) was applied to study the global SO₂ diffusion from the Tonga volcano eruption in January 2022. The SO₂ source was evaluated and designed based on satellite monitoring information, and the numerical simulation was conducted untill 20th February 2022. The model presented a rather narrower extent of SO₂ diffusion in north-south direction in the early stage of the volcano eruption. Later on, the simulated diffusion extent was graduallly in consistent with the observations. The SO₂ was mainly concentrated in the southern hemisphere, and the westward transmission region was in the latitudes from 0 to 30ºS with a maximum transmission velocity of 22.5º/d. The trans-equatorial transmission was weak in the study period and with weak influence on the northern hemisphere and China. The westward transmission of SO₂ showed inclined shape with higher front and lower rear. The rapidest upward transmission height and the maximum diffusion height were about 27km and 31km respectively. To February 20th, the SO₂ deposition was discovered rarely in a large extent to south of 60ºN, the most parts of the world. The main deposition area was located in the latitudes form 0to 50ºS, and the strongest deposition areas were located in eastern Australia, northwest of Tonga volcano, and in southern parts of South America. The research results can provide data support and ideas for Tonga volcano climate effect assessment.