Long range transport and fate of a stratospheric volcanic cloud from Soufrière Hills volcano, Montserrat

[摘要] Volcanic eruptions emit gases, ash particles and hydrometeors into theatmosphere, occasionally reaching heights of 20 km or more, to reside in thestratospheric overworld where they affect the radiative balance of theatmosphere and the Earth's climate. Here we use satellite measurements and aLagrangian particle dispersion model to determine the mass loadings,vertical penetration, horizontal extent, dispersion and transport ofvolcanic gases and particles in the stratosphere from the volcanic cloudemitted during the 20 May 2006 eruption of Soufrière Hills volcano,Montserrat, West Indies. Infrared, ultraviolet and microwave radiationmeasurements from two polar orbiters are used to quantify the gases andparticles, and track the movement of the cloud for 23 days, over a distanceof ~18 000 km. Approximately, 0.1±0.01 Tg(S) was injected intothe stratosphere in the form of SO₂: the largest single sulphur inputto the stratosphere in 2006. Microwave Limb Sounder measurements indicate anenhanced mass of HCl of ~0.003–0.01 Tg. Geosynchronous satellite datareveal the rapid nature of the stratospheric injection and indicate that theeruption cloud contained ~2 Tg of ice, with very little ash reachingthe stratosphere. These new satellite measurements of volcanic gases andparticles can be used to test the sensitivity of climate to volcanic forcingand assess the impact of stratospheric sulphates on climate cooling.

[学科分类] 大气科学