Determinant Role of Aerosols from Industrial Sources in Hurricane Harvey’s Catastrophe

The destructive power of tropical cyclones is driven by latent heat released from water 36 condensation and is inevitably linked to the abundance of aerosols as cloud condensation nuclei. 37 However, the aerosol effects are unaccounted for in most operational hurricane forecast models. 38 We combined multi-source measurements and cloud-resolving model simulations to show 39 fundamentally altered cloud microphysical and thermodynamic processes by anthropogenic 40 aerosols during Hurricane Harvey. Our observations reveal intense lightning and precipitation in 41 the proximity of Houston industrial areas, and these hotspots exhibit a striking geographic 42 similarity to a decadal climatological maximum of lightning flash density in the south-central U.S. 43 Our ensemble cloud-resolving simulations of Hurricane Harvey indicate that anthropogenic 44 aerosols can increase precipitation and lightning by a factor of 2 in the Houston urban area, 45 unraveling the key factor in regulating flooding during this weather extreme.