The initial dispersal and radiative forcing of a Northern Hemisphere mid-latitude super volcano: a model study
The initial dispersal and radiative forcing of a Northern Hemisphere mid-latitude super volcano: a model study
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北半球中纬度超级火山的初始扩散和辐射强迫：模型研究
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发表时间：
2006
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影响因子：
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通讯作者：
H.
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文献类型：
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作者：
C. Timmreck;H.
利用化学气候模式MAECHAM4/CHEM，结合火山气溶胶和臭氧的相互作用和预报作用，研究了一次可能的北半球中纬度超喷发的初始扩散和辐射强迫。由于海洋表面温度保持不变，因此不分析对流层气候异常。我们的实验表明，位于威斯康星州黄石公园的超级强震在全球范围内的扩散。很大程度上取决于喷发的季节。与夏季相比，北半球夏季火山云团向西优先向南输送，而北半球冬季火山云云向东偏北输送。气溶胶引起的加热导致更多的全球扩散，并伴随着明显的越赤道输送。对于夏季喷发，气溶胶被输送到南半球的距离比冬季喷发远得多。与Pinatubo个例对比，热带高空气旋喷发后3个月出现了较强的降温趋势，最大降温峰值不到1.6K/d。随着时间的推移，这种强烈的冷却效应随着气溶胶密度的降低而减弱，并最初阻止了气溶胶负载的空气进一步活跃上升。地表低于32W/m2的全天净辐射通量变化大约是皮纳图博喷发的6倍。头几个月，热带和亚热带地区出现了大于16W/m2的大的正通量异常。这些强大的作用力需要一个完全耦合的海洋/大气/化学模型来研究气候对这种超级喷发的敏感性。
The chemistry climate model MAECHAM4/ CHEM with interactive and prognostic volcanic aerosol and ozone was used to study the initial dispersal and radiative forcing of a possible Northern Hemisphere mid-latitude su- per eruption. Tropospheric climate anomalies are not analy- sed since sea surface temperatures are kept fixed. Our ex- periments show that the global dispersal of a super erup- tion located at Yellowstone, Wy. is strongly dependent on the season of the eruption. In Northern Hemisphere summer the volcanic cloud is transported westward and preferentially southward, while in Northern Hemisphere winter the cloud is transported eastward and more northward compared to the summer case. Aerosol induced heating leads to a more global spreading with a pronounced cross equatorial transport. For a summer eruption aerosol is transported much further to the Southern Hemisphere than for a winter eruption. In con- trast to Pinatubo case studies, strong cooling tendencies ap- pear with maximum peak values of less than 1.6 K/day three months after the eruption in the upper tropical strato- sphere. This strong cooling effect weakens with decreasing aerosol density over time and initially prevents the aerosol laden air from further active rising. All-sky net radiative flux changes of less than 32 W/m 2 at the surface are about a fac- tor of 6 larger than for the Pinatubo eruption. Large positive flux anomalies of more than 16 W/m 2 are found in the first months in the tropics and sub tropics. These strong forcings call for a fully coupled ocean/atmosphere/chemistry model to study climate sensitivity to such a super-eruption.