Landfalling tropical cyclones perturb Earth‘s rotation

When I read that a large earthquake can alter Earth’s rotation, I found myself wondering: could a typhoon do the same? It seemed unlikely — a storm, however powerful, is not a seismic rupture. But initial intuition is not always reasonable, and I decided to pursue it seriously. I approached the problem from three directions: a simplified theoretical model built on angular momentum budgets, a numerical simulation of typhoon landfall in the cloud-resolving model CM1, and an analysis of observational data from real typhoon events. All three converged on the same answer: a major typhoon can produce a perturbation to Earth’s rotation that exceeds that of a large earthquake. I did not expect that result, and I have not stopped thinking about it since.