Ocean Response to the Pinatubo and Year 1259 Volcanic Eruptions

Abstract

The ocean's response to the Pinatubo and 1259 volcanic eruptions are investigated using an ocean general circulation model equipped with an energy balance model. Two numerical experiments are simulated. The first experiment features the Pinatubo eruption and the second experiment simulates the much larger volcanic eruption occurred at 1259 when the radiative forcing reduced by 7 times the Pinatubo case. With the reduced radiative forcing due to the Pinatubo eruption by about 3 W m- 2 and 1259 eruption by about 21 W m-2, the global mean sea surface temperature (SST) decrease peaks in the second year by about 0.4°C and 1.6°C, respectively. Sea surface salinity (SSS) increases substantially in the northern North Pacific, northern North Atlantic, and the Southern Ocean. The reduced SST together with SSS increases ocean convection, which yields an increase in North Atlantic Deep Water, Antarctic Bottom Water, and North Pacific Intermediate Water production and their outflows. The increase in overturning circulation eventually increases the pole-ward ocean heat fluxes. In conclusion, the huge volcanic eruption perturbs the ocean substantially and its signature lasts for more than a decade, confirming the importance of the volcanic eruptions in illustrating the decadal-climate variability recorded in the paleoclimate proxy data for the past million years.e Pinatubo eruption and the second experiment simulates the much larger volcanic eruption occurred at 1259 when the radiative forcing reduced by 7 times the Pinatubo case. With the reduced radiative forcing due to the Pinatubo eruption by about 3 W m- 2 and 1259 eruption by about 21 W m-2, the global mean sea surface temperature (SST) decrease peaks in the second year by about 0.4°C and 1.6°C, respectively. Sea surface salinity (SSS) increases substantially in the northern North Pacific, northern North Atlantic, and the Southern Ocean. The reduced SST together with SSS increases o