Transport in the Stratosphere at Low Latitudes and the Quasi-Biennial Oscillation

平流层中从热带向温带的输送主要是通过等熵平流搅拌进入冬季半球中纬度的活动冲浪区。输送耦合了两个不同成分浓度的区域：（上升流）热带地区和（主要是下升流）温带地区。除季节变化外，这种输送还受到准两年振荡（QBO）的影响。本研究的主要目的是研究QBO通过(a)其平均经向环流，(b)其对低纬度罗斯比波传播和破裂的调制，(c)其对温带罗斯比波活动和surf - zone混合的调制，以及(d)其对冬季全球Brewer-Dobson剩余环流强度的调制来影响输送的方式。这项研究将主要依靠中间大气的三维模型和示踪剂输送模型的数值模拟。这些结果将与其他模拟和卫星观测的中大气进行比较。这项工作还将提供每个季节和QBO的不同阶段从热带到温带的平流层运输率随高度的函数的估计。奥沙利文博士是一位年轻的科学家，在中大气研究界建立了良好的声誉。他的工作不仅有助于更好地理解平流层动力学，而且还提供了影响该地区光化学过程的关键信息。＊＊＊

9634394 O'Sullivan Transport from the tropics to the extratropics in the stratosphere occurs mainly by isentropic advection and stirring into the active surf zone of the winter hemisphere midlatitudes. The transport couples two regions of differing constituent concentrations: the (upwelling) tropical region and the (mostly downwelling) extratropics. Besides varying seasonally, such transport is affected by the quasi-biennial oscillation (QBO). The principal objective of this research is to investigate the manner in which the QBO affects transport by (a) its mean meridional circulations, (b) its modulation of Rossby wave propagation and breaking at the low latitudes, (c) its modulation of the extratropical Rossby wave activity and surf zone mixing, and consequently (d) its modulation of the global Brewer-Dobson residual circulation strength during the winter season. The study will rely primarily on numerical simulations with a three-dimensional model of the middle atmosphere and a tracer transport model. The results will be compared with other simulations and satellite observations of the middle atmosphere. This work will also provide estimates of stratospheric transport rates form the tropics to the extratropics for each season and for different phases of the QBO as a function of height. Dr. O'Sullivan is a young scientist who has established an excellent reputation in the middle atmosphere research community. His work is contributes not only to better understanding of stratospheric dynamics, but also provides critical information on processes that affect the photochemical processes of the region as well. ***