On the Water Vapor Isotopic Composition of Cold Pools in Tropical Boundary Layers

Stable water isotopes are useful tools in the study of the Earth system, with applications ranging from paleoclimatology to groundwater hydrology. A deeper understanding of how the hydrological cycle affects stable water isotopes is therefore of great importance. In this effort, the development of isotope-enabled numerical models has provided a highly controlled environment where this relationship can be investigated in great detail. Here, we will show how a combination of an isotope-enabled cloud resolving model and Lagrangian particle tracking techniques can be used to gain a process-level understanding of the water vapor isotopic composition of certain aspects of deep convective systems. We will present statistics obtained through Lagrangian particle tracking of the isotopic composition of cold pools as a function of height, radius, and cold pool age. Next, we will focus on the coupling between cold pools and the downdrafts that generate them, and we will discuss how the isotopic composition of the two are related. We will also show how the isotopic composition of the moisture rings surrounding cold pool gust fronts can be used to constrain how much rain evaporation occurred in downdrafts. Finally, we will compare the effects of gust front entrainment and surface latent heat fluxes on the isotopic composition of cold pools at various stages of their life cycle.