Dynamics of Surface pCO2 and Sea-air CO2 across the Subtropical to Subarctic Northwest Pacific Ocean
Addey Charles Izuma 1,2, Dai Minhai1, 2, *, Jiang Zong-Pei 3, Coronado-Alvarez Luz De Lourdes 5, Adesina Rasheed Babatunde 3,4
1. College of Ocean and Earth Sciences, Xiamen University, China
2. State Key Laboratory of Marine Environmental Science, Xiamen University, China 3. Ocean College, Zhejiang University, Zhoushan, China
4. Department of Marine Science and Technology, Federal University of Technology, Akure, Nigeria
5. Instituto de Investigaciones Oceanológicas, Autonomous University of Baja California, Mexico
The partial pressure of carbon dioxide (pCO2) and air-sea CO2 flux in the Northwest Pacific Ocean was investigated based on data from satellite observation in 2019. The study area was divided based on latitudinal difference: (A = 25-39N, B = 40-44N, and C = 45-60N). The seasonal pCO2 variations in region A had a positive correlation with SST, acting as a sink for atmospheric CO2 in winter and a weak source of CO2 to the atmosphere in late summer, and an overall annual estimated pCO2 of 370.7 µatm and CO2 uptake of -2.31 mol m-2 yr-1. In contrast to region A, pCO2 seasonal variability in both B and C correlated negatively with SST. Both regions had similar trends of winter-spring maxima associated with entrainment of subsurface water and summer-autumn minima resulting from biological drawdown. The annual surface pCO2 in region C (403 µatm) was typically higher than those in region B (373.6 µatm), with significant contribution during wintertime owing to enhanced vertical mixing and the increased CO2 solubility (due to lower SST) at higher latitudes. Region C acted as a CO2 source to the atmosphere with an annual emission of 0.32 mol m-2 yr-1, while region B was a sink of -2.57 mol m-2 yr-1. On average, the entire region acted as an annual sink of -1.52 mol m-2 yr-1. The large variability observed in the study region is due to the coupled effects of dynamical processes such as SST change, Kuroshio-Oyashio currents, vertical mixing, and biological activities.
Keywords: Seawater CO2 partial pressure, air-sea CO2 fluxes, Northwest Pacific Ocean, Vertical mixing, Kuroshio-Oyashio current.
Commentaires