QBO Changes in CMIP6 Climate Projections
QBO Changes in CMIP6 Climate Projections
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DOI：
10.1029/2019gl086903
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发表时间：
2020-04-16
影响因子：
5.2
通讯作者：
Wu, Tongwen
中科院分区：
文献类型：
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作者：
Butchart, Neal;Anstey, James A.;Wu, Tongwen
耦合模式相互比较项目(CMIP6)的第六阶段是第一次有相当数量的模式包括分辨率良好的平流层。在具有实际准两年振荡(QBO)的10个模式中，研究了历史和共享社会经济路径(SSP)情景模拟中赤道平流层变率的变化。所有这些都预测，对于SSP370和SSP585情景以及1960年至2010年，QBO将在整个平流层减弱。SSP585、SSP370和历史模拟的减弱在平流层下部最强，分别为每十年5.8+/-0.5%到4.3+/-0.5%到2.0+/-0.5%。在20百帕，虽然在10个模式中只有7个模式出现了向东减弱的阶段，但西向和向东两个阶段的减弱都有贡献。温度QBO也有类似的强烈减弱，但仅从30百帕以上。在这两种情况下，QBO周期在10个模式中有7个模式减少。简而言之，在大约16到50公里的高度，赤道大气主要是由强纬向风主导的，大约每14个月从东向西反转一次，这被称为准两年振荡。随着模型的发展，这种准两年一次的振荡现在出现在大量最新的气候预测中。在那些以振荡为特征的预测中，对于所考虑的更极端的情景，气候变化使其每十年最多减弱6%。有些不太确定的是，在几个预测中，风向逆转之间的时间缩短了。
Phase 6 of the Coupled-Model Intercomparison Project (CMIP6) is the first in which a significant number of models include a well-resolved stratosphere. Changes in equatorial stratospheric variability in historical and Shared Socioeconomic Pathways (SSPs) scenario simulations are investigated in 10 models with realistic quasi-biennial oscillations (QBO). All project a weakening of the QBO throughout the stratosphere for SSP370 and SSP585 scenarios and for 1960 to 2010. The weakening is strongest in the lower stratosphere, ranging from 5.8 +/- 0.5% to 4.3 +/- 0.5% to 2.0 +/- 0.5% per decade at 50 hPa for SSP585, SSP370, and historical simulations, respectively. At 20 hPa a weakening of both westward and eastward phases contributes though the weakening eastward phase is only seen in 7 of the 10 models. Similar robust weakening occurs for the temperature QBO, but only from 30 hPa upward. In both scenarios the QBO period decreases in 7 of the 10 models.Plain Language Summary At altitudes between roughly 16 and 50 km the equatorial atmosphere is dominated by strong zonal winds that reverse sign from eastward to westward roughly every 14 months in what is referred to as the quasi-biennial oscillation. With developments in models the quasi-biennial oscillation now features in a significant number of the latest state-of-the-art climate projections. In those projections featuring the oscillation, the changing climate weakens it by up to similar to 6% per decade for the more extreme of the scenarios considered. Somewhat less certain is a shortening of the time between wind reversals in several of the projections.