Seasonality and extent of extratropical TST derived from in-situ CO measurements during SPURT
Seasonality and extent of extratropical TST derived from in-situ CO measurements during SPURT
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SPURT 期间原位 CO 测量得出的温带 TST 的季节性和范围
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
H. Fischer
中科院分区：
文献类型：
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作者：
P. Hoor;C. Gurk;D. Brunner;M. Hegglin;H. Wernli;H. Fischer
抽象。我们提出了空中原位微量气体测量，这是在2001年11月和2003年7月之间的SPURT-项目（SPURenstofftransfer在der对流层顶区域，微量气体运输在对流层顶区域）的8个运动进行。通过准定期的观测，可以大致了解欧洲35° ~ 75 ° N对流层顶区微量气体分布的季节变化，以研究对流层顶外的输送和混合对平流层最低层的影响。从CO和O3的相关性，对流层空气不可逆混合到最低平流层被确定。CO的分布表明，运输和随后的混合对流层空气在对流层顶外主要影响一个层，它密切遵循当地对流层顶的形状。此外，CO2的季节循环说明了该层与对流层外的强耦合.等熵线上CO的水平梯度和平流层最低层CO-O3-的分布都表明，随着距对流层顶距离的增加，准水平输送和随后的混合作用的影响逐渐减弱。混合层延伸到当地对流层顶上方的位温约25 K，仅表现出较弱的季节性。然而，在离对流层顶很远的地方，对流层空气的重要影响仍然很明显。N2 O与CO2的关系表明，热带对流层顶的大气对平流层最低层的背景大气有重要贡献。
Abstract. We present airborne in-situ trace gas measurements which were performed on eight campaigns between November 2001 and July 2003 during the SPURT-project (SPURenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region). The measurements on a quasi regular basis allowed an overview of the seasonal variations of the trace gas distribution in the tropopause region over Europe from 35°-75°N to investigate the influence of transport and mixing across the extratropical tropopause on the lowermost stratosphere. From the correlation of CO and O 3 irreversible mixing of tropospheric air into the lowermost stratosphere is identified. The CO distribution indicates that transport and subsequent mixing of tropospheric air across the extratropical tropopause predominantly affects a layer, which closely follows the shape of the local tropopause. In addition, the seasonal cycle of CO 2 illustrates the strong coupling of that layer to the extratropical troposphere. Both, horizontal gradients of CO on isentropes as well as the CO-O 3 -distribution in the lowermost stratosphere reveal that the influence of quasi-horizontal transport and subsequent mixing weakens with distance from the local tropopause. The mixing layer extends to about 25 K in potential temperature above the local tropopause exhibiting only a weak seasonality. However, at large distances from the tropopause a significant influence of tropospheric air is still evident. The relation between N 2 O and CO 2 indicates that a significant contribution of air originating from the tropical tropopause contributes to the background air in the extratropical lowermost stratosphere.