Typhoon-Induced Variability of the Oceanic Surface Mixed Layer Observed by Argo Floats in the Western North Pacific Ocean

This study takes advantage of the newly established observational network of Argo floats to investigate the variability of the oceanic surface mixed layer (ML) in response to typhoons occurring over the period 2000-08 in the western North Pacific Ocean. After removing the background variability due to the seasonal cycle, the regionally averaged ML response is statistically analyzed as a function of the distance from the typhoon centre, the time after typhoon passage, the geographic location, the translation speed of the typhoon and the pre-existing patterns of oceanic circulation. Based on an unprecedented amount of new observational data, our analysis reveals some notable differences between ML temperature and ML depth changes induced by a typhoon, including the delayed response of ML temperature relative to ML depth, the longer restoring time of ML temperature, and the tendency of pre-existing cold-core features to favour ML cooling while warm-core features favour ML deepening.