Aircraft studies find high supersaturation that could let aerosols invigorate tropical storms

Aircraft observations show tropical convective clouds can reach water-vapor supersaturation high enough for fine aerosols to form extra droplets and potentially strengthen updrafts, ScienceDaily reported, citing work in Advances in Atmospheric Sciences. Researchers from China, the United States, and Israel analyzed NASA Cloud, Aerosol and Monsoon Processes Philippines Experiment flights over the Philippines and nearby oceans in 2019. They estimated quasi-steady-state supersaturation from updraft speeds and droplet size distributions and found levels far higher than many earlier aircraft studies, rising to about 10% near -5°C where updrafts were still mostly supercooled liquid. A companion Journal of Geophysical Research: Atmospheres analysis of ESCAPE flights over coastal Texas and Louisiana independently found rare supersaturation near 11% in deep convective updrafts. Highest reliable values appeared in strong, relatively clean updrafts with fewer droplets. Daniel Rosenfeld of The Hebrew University of Jerusalem and Wuhan University said earlier work often sampled polluted or shallow clouds that rarely create those conditions. ScienceDaily stresses the observations show required conditions can exist, not that aerosols caused the sampled storms to strengthen. Primary paper DOI: 10.1007/s00376-026-5894-y.