Journal of Marine Science and Engineering

8 (10)

SCIE

[논문]Typhoon-Triggered Phytoplankton Bloom and Associated Upper-Ocean Conditions in the Northwestern Pacific: Evidence from Satellite Remote Sensing, Argo Profile, and an Ocean Circulation Model

Joon-Ho Lee

Jae-Hong Moon

Taekyun Kim

Along-lastingphytoplanktonbloom, characterizedbyhighchlorophyll-a (Chl-a) concentrations
in an eddy-like feature,was detected inMODIS satellite imagery of the northwestern Pacific following the
passage of Typhoon Krosa in August 2019. Satellite datasets, Argo measurements, and regional ocean
models were analyzed to determine the occurrence and abundance of high-Chl-a concentrations and
the upper-ocean conditions associated with them before and after the passage of the typhoon. Remote
sensing data revealed that the typhoon triggered sharp increases in surface Chl-a concentrations more
than five times the pre-typhoon average, which lasted for two weeks. The elevated post-typhoon
concentrations coincided with a pre-existing oceanic cyclone that was detected as an altimetry-based
sea surface height anomaly. The typhoon looped around the oceanic cyclone and lingered for two days
at slow speeds (less than 2 m/s), producing an unusual sea-surface cooling of up to approximately
9 C in the cyclonic eddy region. Our model successfully captured the typhoon-induced cold-core
cyclonic circulation, which corresponded to the region of high Chl-a concentration. Model–data
comparisons revealed that the looping motion of the slow-moving typhoon enhanced the pre-existing
cyclonic circulation, resulting in strong vertical mixing and upwelling, consequently initiating a
phytoplankton bloom due to increased nutrient supply to the euphotic zone.

2020-10-10

https://doi.org/10.3390/jmse8100788