Coupled physical-biogeochemical modeling investigation on the upper ocean physical and biogeochemical responses to passages of 46 major hurricanes in the Northwest Atlantic Ocean: A historical synthesis

Haibo Zong, North Carolina State University, Raleigh, NC, United States and Ruoying He, North Carolina State Univ., Raleigh, NC, United States
Abstract:
Hurricane-driven ocean upwelling brings colder, nutrient-rich and carbon-rich deep water to the upper ocean column, significantly influencing ocean surface physical and biogeochemical properties. At the same time, strong wind speed and mixing associated with each hurricane also introduce strong gas transport rate, and air-sea CO2 flux. To quantify the upper ocean physical and biogeochemical response to passages of major Atlantic hurricanes, a coupled physical-biogeochemical modeling system was developed and applied to simulate the northwest Atlantic ocean responses to 46 historical hurricanes during 2007-2017. Impacts of these hurricanes on sea surface temperature, nitrate, dissolved inorganic carbon (DIC), water pCO2, and air-sea CO2 flux were statistically evaluated and synthesized. Our results show that both SST and surface water pCO2 decreased during passages of all hurricanes due to upwelling processes. The responses of nitrate, DIC and CO2 flux however are much more complex, and they are related closely to intrinsic storm characteristics including strom’s spatial range, translation speed, and intensity.