Mount Pinatubo’s effect on the moisture-based drivers of plant productivity

Abstract. Large volcanic eruptions can significantly affect the state of the climate, including stratospheric sulfate concentrations, surface and top-of-atmosphere radiative fluxes, stratospheric and surface temperature, and regional hydroclimate. The prevalence of higher natural variability in how the regional rainfall responds to the volcanic-induced climate perturbations creates a knowledge gap in understanding of how eruptions affect ecohydrological conditions and plant productivity. Here we will explore the understudied store (soil moisture) and flux (evapotranspiration) of water as the short-term ecohydrological control over plant productivity in response to the 1991 eruption of Mt. Pinatubo. We used the NASA’s Earth system model for modeling of the 1991’s Mt. Pinatubo eruption and detection of hydroclimate response. The model simulates a radiative perturbation of -5 Wm^-2 and mean surface cooling of ~ 0.5 °C following the Mt. Pinatubo eruption in 1991. The rainfall response is spatially heterogenous, due to dominating variability, yet still shows suppressed rainfall in the northern hemisphere after the eruption. We find that up to 10–15 % of land regions show a statistically significant agricultural response. Results confirm that these higher-order impacts successfully present a more robust understanding of inferred plant productivity impacts. Our results also explain the geographical dependence of various contributing factors to the compound response and their implications for exploring the climate impacts of such episodic forcings.