The impact of microphysics on tropical precipitation extremes is
explored with a global storm-resolving model by modifying the terminal
velocity of raindrops. Depending on the time scales, precipitation
extremes respond differently. Hourly extremes are influenced dynamically
through convective updraft speed, as a faster terminal velocity of
raindrops increases the updraft speed by reducing the total rain in the
atmosphere which increases the updraft buoyancy. However, the response
of daily precipitation extremes is more sensitive to the microphysical
modulation on convective organization. By being more organized with
decreasing terminal velocity, daily precipitation extremes are enhanced
due to increased precipitation efficiency and intensified updrafts.
Thus, the results suggest that microphysics, despite often occurring at
small scales, can influence the circulation at larger scales, and the
microphysical imprint across different scales plays an important role in
regulating tropical precipitation extremes.