Narrowing of the ITCZ in a warming climate: Physical mechanisms
Narrowing of the ITCZ in a warming climate: Physical mechanisms
复制标题
DOI：
10.1002/2016gl070396
复制
发表时间：
2016-11-01
影响因子：
5.2
通讯作者：
Schneider, Tapio
中科院分区：
文献类型：
--
作者：
Byrne, Michael P.;Schneider, Tapio
在观测和气候模型中，热带辐合带（ITCZ）因全球变暖而缩小。然而，缺乏对这种缩小的物理理解。在这里，我们表明，未来气候模拟中 ITCZ 的缩小与湿静态能量 (MSE) 预算的变化有关。平均环流造成的 MSE 平流和瞬变涡流造成的 MSE 散度往往会使 ITCZ 变窄，而大气净能量输入和总湿稳定性的变化往往会使 ITCZ 变宽。出现缩小趋势的原因是经向 MSE 梯度随着变暖而加强，而最大的加宽趋势是由于大气短波加热的增加。 ITCZ 缩小的幅度在很大程度上取决于总湿润稳定性和云层，这强调需要更好地了解热带大气中的这些基本过程。
The Intertropical Convergence Zone (ITCZ) narrows in response to global warming in both observations and climate models. However, a physical understanding of this narrowing is lacking. Here we show that the narrowing of the ITCZ in simulations of future climate is related to changes in the moist static energy (MSE) budget. MSE advection by the mean circulation and MSE divergence by transient eddies tend to narrow the ITCZ, while changes in net energy input to the atmosphere and the gross moist stability tend to widen the ITCZ. The narrowing tendency arises because the meridional MSE gradient strengthens with warming, whereas the largest widening tendency is due to increasing shortwave heating of the atmosphere. The magnitude of the ITCZ narrowing depends strongly on the gross moist stability and clouds, emphasizing the need to better understand these fundamental processes in the tropical atmosphere.