Enhanced latent heat flux with moisture disequilibrium during rapid intensification of the strongest supertyphoon Mangkhut in 2018

A summertime field survey in 2018 has been carried out to investigate the air-sea interaction over warm eddy in the Northwest Pacific. The strongest Supertyphoon Mangkhut in the Northwest Pacific got rapidly intensified from 80 kts to 120 kts during Sep.10, 2018, and it lasted as category 5 typhoon during Sep. 11 to 14. The maximum wind speed during intensification reached 100 kts on Sep.10. At distance 500 km off typhoon track the observations by sensors equipped on wave gliders were carried out in order to measure air-sea interaction parameters, as well as using instruments equipped on research vessel Isabu.

During the intensification of typhoon Mangkhut the enhanced bulk latent heat fluxes (LHF) were estimated over the several days. The latent heat flux was estimated from gust wind and 1 minute mean parameters. Peak LHF from gust wind reached over 1,100 W/m2, while 1 minute mean LHF reached about 900 W/m2. Data analysis reveals that the enhanced heat flux appears to exist due to an increase in moisture disequilibrium between the ocean and atmosphere. This supports the hypothesis that enhanced buoyant forcing from the ocean is likely to be an important mechanism in tropical cyclones over warm oceanic mesoscale eddy (Jaimes et al., 2016).

This work was supported by the project of “Study on air-sea interaction and process of rapidly intensifying typhoon in the Northwestern Pacific” funded by the Ministry of Ocean and Fisheries, Korea,