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Interannual variability of the air-sea CO2 flux in the north Indian Ocean

Valsala, V and Maksyutov, S (2013) Interannual variability of the air-sea CO2 flux in the north Indian Ocean. Ocean Dynamics, 63 (2-3). pp. 165-178.

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A simple biogeochemical model coupled to an offline ocean tracer transport model driven by reanalysis ocean data is used to simulate the seasonal and interannual CO2 flux variability in the northern Indian Ocean. The maximum of seasonal and interannual CO2 emission variances in the northern Indian Ocean are located in the coastal Arabian Sea (AS) and Southern Peninsular India (SP) with a basin-wide seasonal amplitude and standard deviation of 0.044 ± 0.04 Pg C year ⁻¹. The area integrated CO2 emissions from these two regions in the model are significantly correlated (above a 95 level) with the observations of Takahashi et al. (Deep-Sea Res-II, 56:554-577, 2009). The interannual anomalies of CO2 emission from the AS and SP are found as 40 and 30 of their respective seasonal amplitudes. Both the Arabian Sea (AS) and Southern Peninsular India (SP) interannual CO2 emission anomalies show a 3-4-year variability. The correlations of AS and SP CO2 emission anomalies with the Indian Ocean Dipole/Zonal Mode (IODZM) and Southern Oscillation (SO) indices from 1980 to 1999 are 0.35, 0.21 and 0.32, 0.01 respectively. A 5-year window moving correlation analysis shows that the relationship of AS and SP CO2 emission to the SO and IODZM are complementary to each other. During the years when the correlation of air-sea CO2 emission with the IODZM is stronger, the corresponding correlation with the SO is weaker or opposite. The total change in pCO 2 is broken down into changes induced by the individual components such as dissolved inorganic carbon (DIC), sea surface temperature (SST), alkalinity, and salinity and found that (1) the effect of SST in the AS CO 2 emission increases (decreases) when the correlation of CO 2 emission with the IODZM is positive (negative), and (2) the SP CO2 emission is strongly controlled by the circulation-driven DIC changes; however, this relation is found to be weaker when the SO correlates negatively with the SP CO2 emission.

Item Type: Article
Additional Information: Copyright of this article belongs to Springer.
Uncontrolled Keywords: Air-sea co; Biogeochemical cycle; ENSO; Indian ocean; Interannual variability; IODZM, Atmospheric pressure; Atmospheric temperature; Biogeochemistry; Oceanography, Carbon dioxide, amplitude; annual variation; atmosphere-ocean coupling; biogeochemical cycle; carbon dioxide; carbon emission; dissolved inorganic carbon; seasonal variation; Southern Oscillation, Arabian Sea; India; Indian Ocean
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 11 Jun 2014 07:13
Last Modified: 11 Jun 2014 07:13

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