Abstract The impacts of dry air on tropical cyclone (TC) development at different latitudes with no mean flows are investigated with idealized simulations. It is found that the effective radius of the dry air is sensitive to its vertical distribution and the background earth rotation. The effect of low-level dry-air layer in inhibiting TC development decreases with increasing latitude. At lower latitudes, the greater boundary layer gradient wind imbalance results in a strong low-level inflow, and the dry air can easily penetrate into the TC inner-core region. The intruding dry air inhibits the inner-core deep convection and leads to marked asymmetric convective structure, which significantly suppresses TC development. In contrast, at higher latitudes, the dry air gets moistened before reaching the TC inner-core region due to a weaker radial inflow but can suppress the development of the outer spiral rainbands. The suppressed outer spiral rainbands lead to a weaker barrier effect to the boundary layer inflow and help TC development. Furthermore, the lower the altitude of dry-air layer resides, the greater the impact on TC intensification. The low-level pathway associated with the boundary layer inflow plays an important role on how dry-air layer acts on a TC without considering the mean flow effects. Through examining the climatological distribution of the moisture field, we expect that the intrusion of dry air can be more frequent in the North Atlantic area and therefore has more effects on TC development than in the western North Pacific.

中文翻译：

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干空气效应对热带气旋发展的纬度依赖性

摘要 通过理想化模拟研究了干燥空气对不同纬度无平均流量的热带气旋（TC）发展的影响。发现干空气的有效半径对其垂直分布和背景地球自转敏感。低层干空气层抑制TC发展的作用随着纬度的增加而减弱。在低纬度地区，边界层梯度风不平衡较大，导致低层强烈流入，干燥空气容易渗透到台风核心区。侵入的干燥空气抑制了内核深层对流，导致明显的不对称对流结构，显着抑制了TC的发展。相比之下，在高纬度地区，由于径向流入较弱，干燥空气在到达台风内核区之前就被润湿，但可以抑制外螺旋雨带的发展。受抑制的外螺旋雨带对边界层流入的屏障作用减弱，有利于台风的发展。此外，干空气层所在的高度越低，对TC增强的影响越大。在不考虑平均流量效应的情况下，与边界层流入相关的低层路径对干空气层如何作用于 TC 起着重要作用。通过考察湿气场的气候分布，我们预计北大西洋地区干燥空气的侵入可能更频繁，因此对台风发展的影响比西北太平洋地区更大。