Stratospheric Gravity Waves as a Proxy for Hurricane Intensification: A Case Study of Weather Research and Forecast Simulation for Hurricane Joaquin.

We conducted simulations with a 4‐km resolution for Hurricane Joaquin in 2015 using the weather research and forecast (WRF) model. The model data are used to study stratospheric gravity waves (GWs) generated by the hurricane and how they correlate with hurricane intensity. The simulation results show spiral GWs propagating upward and anticlockwise away from the hurricane center. GWs with vertical wavelengths up to 14 km are generated. We find that GW activity is more frequent and intense during hurricane intensification than during weakening, particularly for the most intense GW activity. There are significant correlations between the change of stratospheric GW intensity and hurricane intensity. Therefore, the emergence of intensive stratospheric GW activity may be considered a useful proxy for identifying hurricane intensification. Plain Language Summary: Accurate predictions of changes in hurricane intensity are essential to provide sufficient lead time for warning and evacuation. As a hurricane intensifies, gravity waves (GWs) are emitted into the stratosphere to partially rebalance the sudden energy changes. If a correlation between hurricane intensification and GWs is verified, observing stratospheric GWs with satellite instruments could provide a possible predictor of hurricane intensification. This approach is advantageous when clouds obscure the direct view from above by visible and infrared instruments into the inner state of the hurricane. This study uses mesoscale model simulations to test and verify the correlation between hurricane intensification and GWs and finds that stratospheric GW activity increases prior to peaks in hurricane intensity. Key Points: High‐resolution weather research and forecast simulations for Hurricane Joaquin show spiral gravity waves (GWs) emanating into the stratosphereStratospheric GW activity is more frequent and intense before and during hurricane intensification than during weakeningThis study provides further evidence that stratospheric GW activity is a valid proxy for hurricane intensification [ABSTRACT FROM AUTHOR]