On interpreting studies of tracer transport by deep cumulus convection and its effects on atmospheric chemistry
On interpreting studies of tracer transport by deep cumulus convection and its effects on atmospheric chemistry
复制标题
深积云对流示踪剂输运解释及其对大气化学影响的研究
DOI：
10.5194/acp-8-6037-2008
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发表时间：
2008
影响因子：
6.3
通讯作者：
M. Salzmann
中科院分区：
文献类型：
--
作者：
M. Lawrence;M. Salzmann
全球化学输送模式（CTM）和化学-GCM（CGCM）通常模拟由深对流引起的示踪剂垂直输送，而不是由平均风引起的正面输送，即使平均输送的一部分，例如Hadley和步行者环流，发生在深对流上升气流中。这种垂直输运的分割处理对CTM模拟有各种影响。特别是，它导致了在以前的研究中忽略了一个或多个示踪剂的参数化对流输送的几个敏感性模拟的错误解释。我们描述了这个问题的模拟通量和分数的这些通量代表- ING各种物理和非物理过程。然后，我们表明，有一个显着的重叠，在CTM MATCH的对流和大尺度平均垂直空气质量通量，并讨论了这对解释以前和未来的敏感性模拟的影响，以及简要地指出其他相关的影响，如数值扩散。天气和全球尺度环流。在这里，我们特别关注通过垂直输送的深对流的直接影响。DCC是对流层中空气质量翻转的一个组成部分，快速上升气流将空气质量和示踪剂从边界层输送到对流层上部，并反向从自由对流层进入边界层的下降气流。这对整个大气层中痕量气体和气溶胶的预算产生了深远的影响，特别是对那些寿命在
Global chemistry-transport models (CTMs) and chemistry-GCMs (CGCMs) generally simulate vertical tracer transport by deep convection separately from the ad- vective transport by the mean winds, even though a compo- nent of the mean transport, for instance in the Hadley and Walker cells, occurs in deep convective updrafts. This split treatment of vertical transport has various implications for CTM simulations. In particular, it has led to a misinterpre- tation of several sensitivity simulations in previous studies in which the parameterized convective transport of one or more tracers is neglected. We describe this issue in terms of simulated fluxes and fractions of these fluxes represent- ing various physical and non-physical processes. We then show that there is a significant overlap between the convec- tive and large-scale mean advective vertical air mass fluxes in the CTM MATCH, and discuss the implications which this has for interpreting previous and future sensitivity sim- ulations, as well as briefly noting other related implications such as numerical diffusion. synoptic and global scale circulations. Here we focus specif- ically on the direct effects of deep convection via vertical transport. DCC is an integral part of the overturning of air masses in the troposphere, with rapid updrafts transporting air masses and tracers from the boundary layer to the upper troposphere, and downdrafts in reverse from the free tropo- sphere into the boundary layer. This has profound effects on the budgets of trace gases and aerosols throughout the tro- posphere, particularly on those with lifetimes in the range of