Dramatic tropical storms owe their powerful impact to complex processes taking place in the Earth’s atmosphere. Differences in density drive the movement of air in the atmosphere as warm, moist air rises from the surface of the Earth and meets the colder, denser air of the upper atmosphere. This imbalance is the basis for the winds and weather conditions that define Earth’s climate zones; thus, examining the turbulent behavior of the atmosphere is key to understanding weather patterns and climate conditions.
The tropics are unique because heat transfer here is driven primarily by convection—the tendency of hot air to rise and displace cooler, denser air. The physics of convection are chaotic and complex, however, so scientists are forced to look at its large-scale average behaviors. In a new study, Raymond et al. focused on the troposphere, the lowest layer of the atmosphere, in order to pinpoint broad variables that influence this average convection behavior.
Using results from studies of tropospheric convection during the formation of tropical cyclones, the researchers showed how rotation of the atmosphere in these incipient tropical storms controlled the average properties of convection, including the rainfall it produces, and the effects of convection on the subsequent intensification or dissipation of the storms themselves. The researchers recognized that rotation is a ubiquitous feature of the atmosphere, even in the tropics, and they went on to hypothesize that the complex web of interactions between convection and rotation that is evident in tropical cyclones is central to the dynamics of virtually all important weather features in the tropics.
Additional observations and modeling will help to test these hypotheses and further improve our understanding of the Earth’s atmosphere. (Journal of Advances in Modeling Earth Systems (JAMES), doi:10.1002/2015MS000467, 2015)
—Lily Strelich, Freelance Writer
Citation: Strelich, L. (2015), New insights into the complicated world of tropical convection, Eos, 96, doi:10.1029/2015EO039707. Published on 19 November 2015.