Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Eshkol Eytan

Clouds play a dominant role in Earth's energy budget as they cover more than half of the globe and strongly interact with both solar and terrestrial radiation. Nevertheless, they are poorly understood and represented in models and hence cause high uncertainty in climate prediction. The study of clouds’ processes by remote sensing and quantification of their radiative effects are based on a binary separation between clouds and clear skies that contain aerosol particles. This separation is ambiguous in practice as humidified aerosols continuously grow to become cloud droplets by condensation of water vapor. Moreover, the radiative signal of aerosols and cloud droplets has been shown to overlap and was named the “cloud twilight zone” (CTZ). Eshkol Eytan will work with Graham Feingold, Jake Gristey, Jennifer Kay, and Rainer Volkamer. The studies will use modeling and remote sensing data to quantify the effects of the CTZ on the global energy budget and to study the contribution of different processes to the total CTZ radiative effect. This will help to advance our understanding of clouds’ role in the energy budget and improve remote sensing areas that are neighboring clouds.