Source: WeatherSTEM
Moisture is transported from the subtropics into the equatorial trough by very large convection cells, commonly called trade winds. However, transport of water vapor from the subtropics to the poles occurs more sporadically. Moisture is also circulated around large traveling mid-latitude cyclones and anti-cyclones. This circulation of moisture also transports heat around the planet. For example, heat that is used in the subtropics to evaporate water is carried pole-ward in the form of latent heat and released into the higher latitudes. Recall that this heat transfer is an important aspect of the global energy budget.