Comparison of phytoplankton blooms triggered by two typhoons with different intensities and translation speeds in the South China Sea

Two phytoplankton blooms in the South China Sea (SCS), triggered by 2 typhoons with different intensities and translation speeds, were compared using remotely sensed chlorophylla(chla), sea surface temperature (SST), vector wind field, and best-track typhoon data. Typhoon Ling-Ling in 2001 was strong, with a maximum sustained surface wind speed of 59 m s–1, and fast-moving with a mean translation speed of 4.52 m s–1. Typhoon Kai-Tak in 2005 was weak with a maximum sustained surface wind speed of 46 m s–1, and slow-moving with a mean translation speed of 2.87 m s–1. The weak, slow-moving typhoon Kai-Tak induced phytoplankton blooms with higher chlaconcentrations, while the strong, fast-moving typhoon Ling-Ling induced blooms over a larger area. On average, about 7 typhoons per year affect the SCS, among which 41% are strong (>50 m s–1) and 59% are weak, while 64% are fast-moving (>4.4 m s–1) and 36% are slow-moving. We conservatively estimate that typhoon periods may account for 3.5% of the annual primary production in the oligotrophic SCS.