The Role of Radiative Processes on Cyclone Energetics

Abstract

Radiation-influenced behaviors of tropical cyclones (TC), such as diurnal (cycle of day and night) infrared signals and intensification with global warming, are well documented in literature but lack robust mechanistic explanations. This project studied how radiation affects TC behavior through two different scopes: (1) identifying diurnal patterns of TC behavior in historical data and (2) studying the effect of global warming on TC intensification using global climate model experiments. Through statistical analysis, a diurnal cycle with a morning peak was identified for TC genesis, supporting the theory of how diurnal net longwave cooling affects TC convection, but not for wind-speed intensification. In addition, radiative effects on rapid intensification (RI) were studied by simulating storms in two climate models, one with global warming and the other without. These experiments revealed that RI increases in frequency and magnitude with warming. To explain RI extremization, thermodynamic metrics like potential intensity were analyzed, yet not found to facilitate increasing RI. Finally, an initial analysis of local storm moisture and lifetime intensity changes was performed. Like RI, TC moisture increased significantly with warming. Moreover, RI storms seem to follow distinct intensity trajectories than non-RI storms under global warming, establishing directions for continued research. Refining knowledge of hurricane energetics is crucial for understanding TC development, especially as impacted by continued global warming.