Ozone Transport‐Radiation Feedbacks in the Tropical Tropopause Layer Geophysical Research Letters

The tropical tropopause layer (TTL) temperature balance is of considerable interest for its control over the amount of water entering the stratosphere. The upwelling branch of the Brewer‐Dobson circulation (BDC) directly affects these temperatures through adiabatic cooling. BDC upwelling also indirectly affects TTL temperatures through the influence of ozone transport on radiative heating. We investigate this latter feedback using a single‐column radiative‐convective equilibrium model coupled with a model of simplified stratospheric ozone chemistry and vertical transport. We find that BDC ozone transport is of first‐order importance for TTL temperatures. Additionally, we estimate the effect of ozone transport on cold point tropopause temperature responses to changes in upwelling. We find that the feedback is responsible for approximately 20% of the response to perturbations on time scales longer than about half a year but that this contribution can be neglected for time scales shorter than about a week.

热带对流层顶层（Tropical Tropopause Layer, TTL）的温度平衡因其对进入平流层的水汽含量具有调控作用而备受关注。布鲁尔-多布森环流（Brewer-Dobson Circulation, BDC）的上升支通过绝热冷却直接影响该层温度。此外，BDC上升还通过臭氧输送对辐射加热的影响，间接调控TTL温度。本研究利用耦合了简化平流层臭氧化学与垂直输送模式的单柱辐射对流平衡模型，探究了这一间接反馈过程。研究发现，BDC的臭氧输送对TTL温度具有一级重要性的影响。此外，我们还估算了臭氧输送对上升运动变化所引发的冷点对流层顶温度响应的作用。结果表明，在时长约半年以上的时间尺度上，该反馈贡献了约20%的扰动响应；而在约一周以内的短时间尺度上，这一贡献可忽略不计。