The Asymmetry of Vertical Velocity in Current and Future Climate

Abstract

Abstract A fundamental aspect of vertical velocities in the atmosphere is their asymmetric nature, with stronger upward than downward motions. Here we study this asymmetry from a synoptic‐scale perspective, by employing a storm‐tracking algorithm in observations and climate change simulations. We show that midlatitude cyclones and anticyclones are both skewed toward stronger upward motions, and that this asymmetry intensifies in a warmer climate. Downward motions are generally influenced by changes in the dry static stability, which increases in a warmer climate, and therefore weaken. However, upward motions are influenced by a reduced static stability, which takes into account the influence of latent heating on saturated ascent. The latter decreases locally in regions of upward motions, especially for strong cyclones, leading to an intensification of the upward velocity. The projected increase in the upward velocity of strong storms has potential implications for extreme midlatitude precipitation events.