ABSTRACT: Tropical weather systems are important components of Earth’s climate system—from being key players in redistributing heat and moisture from the tropics to the high latitudes to manifesting into powerful high-impact phenomena (e.g., hurricanes). Despite being so important, the representation of tropical weather systems and their variability is deficient in most climate and weather prediction models. This study tackles this issue by examining the multi-scale variability of tropical weather systems in a hierarchy of idealized model experiments with varying horizontal cell spacing—from 120 km to 3 km. All experiments were produced with the Model for Prediction Across Scales-Atmosphere (MPAS-A). In the first part of this talk, I will introduce a set of MPAS-A aquaplanet experiments and will demonstrate that all experiments capture tropical rainfall variability driven by equatorial waves. In the second part, I will present a novel analysis of the structure of convectively coupled equatorial waves as represented in both aquaplanet and real-data experiments. This analysis shows that convection-permitting resolution captures a more accurate vertical structure due to a better representation of diabatic heating within the equatorial waves. This, in turn, affects the rainfall intensity and evolution of the simulated waves. I will conclude with a discussion of the implications of these results, along with examples of other science topics that could be explored with the MPAS-A aquaplanet experiments.
The Earth Science Colloquium Series, sponsored by Lamont-Doherty Earth Observatory and Columbia University Department of Earth and Environmental Sciences (DEES), provides a lively forum for discussing a wide variety of topics within the Earth sciences and related fields. Colloquia are attended by the full range of scientific and technical staff at LDEO. Colloquium attendance is required of all pre-orals DEES graduate students. The Colloquium Series supports the Lamont Seminar Diversity Initiative.