A closer comparison of early and late-winter atmospheric trends in the northern hemisphere
A closer comparison of early and late-winter atmospheric trends in the northern hemisphere
复制标题
DOI：
10.1175/jcli3468.1
复制
发表时间：
2005-08-15
影响因子：
4.9
通讯作者：
Liu, JP
中科院分区：
文献类型：
--
作者：
Hu, YY;Tung, KK;Liu, JP
利用再分析资料，比较了北半球初冬11-12月(ND)和冬末2-3月(FM)不同区域的年代际趋势。研究发现，1979-2003年间，温带和极地地区ND和FM的年代际变化趋势基本相反。晚冬(FM)的动力趋势表明，极涡变得更强、更冷，从对流层到平流层的波通量变弱，这与早期研究发现的北极涛动(AO)的正趋势相一致，而ND的趋势似乎类似于北极涛动的低指数极性的趋势。在热带地区，哈德利环流在ND和FM都表现出明显的加强，其中FM的加强更强。与Hadley池不同，Ferrel池在ND和FM之间表现出相反的趋势，ND减弱，FM增强。文中还讨论了观测结果与大气环流模式模拟的比较。
Decadal trends are compared in various fields between Northern Hemisphere early winter, November-December (ND), and late-winter, February-March (FM), months using reanalysis data. It is found that in the extratropics and polar region the decadal trends display nearly opposite tendencies between ND and FM during the period from 1979 to 2003. Dynamical trends in late winter (FM) reveal that the polar vortex has become stronger and much colder and wave fluxes from the troposphere to the stratosphere are weaker, consistent with the positive trend of the Arctic Oscillation (AO) as found in earlier studies, while trends in ND appear to resemble a trend toward the low-index polarity of the AO. In the Tropics, the Hadley circulation shows significant intensification in both ND and FM, with stronger intensification in FM. Unlike the Hadley cell, the Ferrel cell shows opposite trends between ND and FM, with weakening in ND and strengthening in FM. Comparison of the observational results with general circulation model simulations is also discussed.