How do Moist Entropy and Moisture Budgets Relate to Tropical Cyclone Development?

Finding the differences between intensifying and non-intensifying tropical cyclones is very important, but complex problem, that includes a wide range of dynamic and thermodynamic variables. One of such thermodynamic variables is the moist entropy in the tropical cyclone. Its changes can indicate the moistening or drying of the storm. We explore the relations between the tropical cyclone development and its moist entropy and moisture tendencies. For that, we use the dropsonde and satellite data from two Atlantic tropical cyclones, Gabrielle (2013) and Edouard (2014). Dropsonde data was collected during NASA's Hurricane and Severe Storm Sentinel (HS3) project, while satellite data comes from NASA's Aqua and Terra satellites. Tropical storm Gabrielle formed in September of 2013 and is a fine example of a non-developing and decaying system. Hurricane Edouard formed a year later and was visited by four research flights in different stages of its life cycle. Two flights into Edouard observed the intensification stage, while the other two happened during decay. This dataset is used to find the differences in moisture and moist entropy budgets between the intensifying and non-intensifying cases, as well as details of those budgets in different stages of tropical cyclone's life-cycle. In addition of calculations of lateral entrainment and surface fluxes of moist entropy, we also estimate radiative cooling and irreversible generation of entropy, in an attempt to estimate the complete moist entropy budget. Our analysis of Edouard and Gabrielle data indicates that the moist entropy tendency is positive for intensifying and negative for non-intensifying situations. On the other hand, the moisture tendency shows stronger dependence on the current state of the storm than on the intensification potential. These results, along with relative importance of all budget contributors will be discussed.