Physical and biological response of the Arabian Sea to tropical cyclone Phyan and its implications

P. Byju (1) , S. Prasanna Kumar (1)

1 NIO - CSIR National Institute of Oceanography [India]

The response to the tropical cyclone Phyan, which developed in the eastern Arabian Sea during 9-11 November 2009, was rapid cooling of sea surface temperature (SST), enhancement of chlorophyll and two-fold increase in net primary productivity (NPP). Cooling of SST was immediate in response to the strong wind mixing, and the subsequent upward Ekman-pumping sustained the cooling even after the dissipation of Phyan. The biological response mediated by the upward Ekman pumping driven vertical transport of subsurface nutrient showed a time lag of 3-4 days. The CO flux to the atmosphere associated with Phyan was 0.123 Tg C, which accounted for ˜85% of the total out-gassing from the eastern Arabian Sea during November. Thus, an increased occurrence of cyclones in a warming environment will lead to an enhanced biomass production and also increase in CO out-gassing.

Mots clés: Tropical cyclone; Arabian Sea; Sea surface temperature; Ekman-pumping; Wind-mixing; Chlorophyll; Primary production; CO out-gassing; Biogeochemical cycle; Nutrients

Domaines: Sciences du Vivant [q-bio]

P. Byju, S. Prasanna Kumar. Physical and biological response of the Arabian Sea to tropical cyclone Phyan and its implications. Marine Environmental Research, 2011, ⟨10.1016/j.marenvres.2011.02.008⟩. ⟨hal-00703489⟩