Wavebreaking and mixing in the northern hemisphere summer stratosphere
Wavebreaking and mixing in the northern hemisphere summer stratosphere
复制标题
北半球夏季平流层的波浪破碎和混合
DOI：
10.1029/2000jd900320
复制
发表时间：
2000
影响因子：
--
通讯作者：
K. Bowman
中科院分区：
文献类型：
--
作者：
R. Wagner;K. Bowman
利用英国气象局（UKMO）平流层观测资料，对北方半球平流层极地臭氧和气溶胶测量II（POAM II）观测到的臭氧纬向变化的原因进行了研究。根据UKMO资料计算的Eliassen-Palm（E-P）通量矢量表明，在北方半球夏季，波动活动从对流层垂直传播到平流层东风。在20 ~ 30 km层，E-P通量散度很小，但不为零。时空功率谱显示，波功率从对流层上部的向东传播波转移到平流层中部的主要向西传播波，符合Charney-Drazin定理的相速滤波。空气包裹的轨迹和有效扩散率的计算显示大量的混合，由于打破了向西传播的波在夏季东风制度。在夏季的混合特性的变化是一致的平均状态和波强迫的变化。我们的结论是，打破大规模的向西传播波在夏季东风造成纬向输送和臭氧变化的观测到的当地最大值。
The cause of zonal ozone variations observed by the Polar Ozone and Aerosol Measurement II (POAM II) instrument in the Northern Hemisphere summer stratosphere from ∼55° to 65°N and ∼20 to 30 km is investigated using United Kingdom Meteorological Office (UKMO) stratospheric data. Eliassen-Palm (E-P) flux vectors calculated from the UKMO data show that wave activity propagates vertically from the troposphere into the stratospheric easterlies during the Northern Hemisphere summer. In the layer between 20 and 30 km the E-P flux divergence is small but nonzero. Space-time power spectra show that wave power shifts from eastward propagating waves in the upper troposphere to predominantly westward propagating waves in the middle stratosphere, consistent with phase speed filtering following the Charney-Drazin theorem. Air parcel trajectories and effective diffusivity calculations show substantial mixing due to breaking of westward propagating waves in the summer easterly wind regime. Changes in mixing properties during the summer season are consistent with changes in the mean state and the wave forcing. We conclude that breaking of large-scale westward propagating waves in the summer easterlies causes meridional transport and the observed local maximum in ozone variability.