Analysis of seasonality and annual mean distribution of atmospheric potential oxygen (APO) in the Pacific region

摘要: [1] We present a data set of atmospheric potential oxygen (APO = O2 + 1.1 × CO2) based on the O2/N2 and CO2measurements flask samples collected at two monitoring stations in Japan commercial cargo ships sailing between U.S./Canada Australia/New Zealand. Since APO is invariant with respect to terrestrial biotic exchange, its variation mainly reflects spatiotemporal distribution air-to-sea gas exchange. From observed for years 2002–2008, we find: (1) elevated annual mean values near equator, (2) large seasonal amplitudes northwestern North Pacific, (3) deep trough low latitudes 20–40°N Western Pacific. In addition, latitudinal distributions timing maximum minimum show asymmetric patterns across equator. Comparing these observations series simulated generated NIES99 transport model driven by climatological oceanic O2 CO2 flux fields, find good agreement except midlatitude. Simulations different mechanisms fluxes reveal that covariation contribute significantly variations northern Pacific; also meridional affects difference cycle. The gradient Southern Hemisphere better reproduced recently revised ocean than previous distribution. 36°N Pacific about 10 per meg lower simulation more recent pCO2 data, suggesting existence additional sinks region. Indeed, performed an sink 30 Tmol yr−1 within region (30–50°N, 120–180°E) reproduces considerably well trough.