Variation of pCO_2 in ocean surface water in response to the passage of a hurricane

摘要

The temporal and spatial variations of pCO_2 in the ocean surface layer in response to the passage of Hurricane Frances (2004) were investigated with a coupled three-dimensional hydrodynamic and carbon model. The results showed that the sea surface temperature cooling was the dominant cause of the decrease of surface pCO_2, while the entrainment of water with higher CO_2 levels partially offset the cooling-induced decrease. The surface distribution of pCO_2 was thus found to mimic the physical deepening processes, with a "right bias" to the hurricane track. The impact of the hurricane on the local air-sea CO_2 exchange extended to about 100 km on both sides of the hurricane track. The whole passage of Hurricane Frances was estimated to have caused a CO_2 efflux of about 3.504-10.363 Tg (1 Tg = 10~(12) g) C from ocean to the atmosphere. Globally, hurricanes in 2004 were estimated to have released a CO_2 efflux of 0.047-0.141 Pg (1 Pg = 10~(15) g) C in total when extrapolating from Hurricane Frances. Under our assumptions, the CO_2 efflux caused by the passages of global hurricanes should have increased by about 71.2%-75.0% in past decades.