Aerosol–cloud–precipitation interactions can lead
to a myriad of responses within shallow cumulus clouds, including an invigoration response, whereby aerosol loading
results in a higher rain rate, more turbulence, and deepening
of the cloud layer. However few global studies have found
direct evidence that invigoration occurs. The few satellitebased studies that report evidence for such effects generally
focus on only the deepening response. Here, we show evidence of invigoration beyond a deepening response by investigating the effects of aerosol loading on the latent heating and vertical motion profiles of warm rain. Using latent
heating and vertical motion profiles derived from CloudSat
radar observations, we show precipitating cumulus clouds in
unstable, polluted environments exhibit a marked increase
in precipitation formation rates and cloud top entrainment
rates. However, invigoration is only discernible when the stability of the boundary layer is explicitly accounted for in
the analysis. Without this environmental constraint, the mean
polluted and pristine cloud responses are indiscernible from
each other due to offsetting cloud responses in stable and unstable environments. Invigoration, or suppression depending
on the environment, may induce possible feedbacks in both
stable and unstable conditions that could subdue or enhance
these effects, respectively. The strength of the invigoration
response is found to additionally depend on cloud organization defined here by the size of the warm rain system. These
results suggest that warm cloud parameterizations must account for not only the possibility of aerosol-induced cloud
invigoration, but also the dependence of this invigorated state
on the environment and the organization of the rain system.
