Climate Studies with a Multilayer Energy Balance Model. Part III: Climatic Impact of Stratospheric Volcanic Aerosols

Abstract

The radiative and climatic effects of stratospheric volcanic aerosols are studied with a multilayer energy balance model. The results show that the latitudinal distribution of aerosols has a significant effect on climate sensitivity. When aerosols are assumed to be distributed uniformly in the 30–90°N region and decay exponentially with an e-folding time constant of 1 year, the maximum response is in the 60–70°N zone where the ice-albedo feedback is most active. The maximum occurs shortly (<0.5 years) after the eruption due to the large extent of land and, therefore, the small thermal inertia in that latitude zone. When the same amount of aerosols is assumed to be in the 0–30°N region, the response is much weakened due to smaller radiative forcing and lack of ice-albedo feedback in the tropics, but is prolonged due to the larger extent of the oceans. The maximum response is reduced to ⅕ of that of the former case and occurs at a much later time (∼1.5 years). A secondary maximum appears in the pol... Abstract The radiative and climatic effects of stratospheric volcanic aerosols are studied with a multilayer energy balance model. The results show that the latitudinal distribution of aerosols has a significant effect on climate sensitivity. When aerosols are assumed to be distributed uniformly in the 30–90°N region and decay exponentially with an e-folding time constant of 1 year, the maximum response is in the 60–70°N zone where the ice-albedo feedback is most active. The maximum occurs shortly (<0.5 years) after the eruption due to the large extent of land and, therefore, the small thermal inertia in that latitude zone. When the same amount of aerosols is assumed to be in the 0–30°N region, the response is much weakened due to smaller radiative forcing and lack of ice-albedo feedback in the tropics, but is prolonged due to the larger extent of the oceans. The maximum response is reduced to ⅕ of that of the former case and occurs at a much later time (∼1.5 years). A secondary maximum appears in the pol...