The Stirring Tropics: The Ubiquity of Moisture Modes and Moisture–Vortex Instability

• DOI: 10.1175/jcli-d-23-0145.1
• Publication Date: 2024-01-19T13:06:32Z
• Authors: Víctor C. Mayta; Ángel F. Adames C...
• Keywords: 0207 environmental engineering; 0105 earth and related environmental sciences

Abstract Observations of column water vapor in the tropics show significant variations space and time, indicating that it is strongly influenced by passage weather systems. It hypothesized many influencing systems are moisture modes, whose thermodynamics governed moisture. On basis four objective criteria, results suggest all oceanic convectively coupled tropical depression (TD)-like waves equatorial Rossby modes. These modes occur where horizontal gradient steep not content high. Despite geographical basic-state differences, driven same mechanisms across basins. The moist static energy (MSE) anomalies propagate westward advection trade winds. Their growth determined background anomalous meridional winds radiative heating. Horizontal maps 850-hPa streamfunction convection partially collocated with low-level circulation nearly waves. Both this structure process indicate grow from moisture–vortex instability. Last, space–time spectral analysis reveals coherent exhibit a phasing consistent poleward latent transport. Collectively, these ubiquitous tropics. That they regions gradients instability suggests inherently unstable subject to continuous stirring. Significance Statement Over tropics, has been found be highly correlated precipitation, especially slowly evolving observations theory support hypothesis exist, type precipitating system does exist dry theory. In study, we varies greatly space, transporting air humid areas toward their low pressure center. climatological-mean distribution stirring