Understanding the impacts dust and bioparticles on mixed phase cloud properties and precipitation processes (Invited Presentation)

Atmospheric aerosols can profoundly impact climate through their ability to act as cloud condensation and ice nuclei in clouds. Globally, ice nucleation plays a critical role in influencing precipitation processes. On average, only one in a million particles can form ice nuclei, a process which is largely controlled by chemistry. Dust and biological particles such as bacteria have been shown to be some of the most efficient ice nuclei, inducing ice nucleation at temperatures as warm as -1 C. Over the past decade, it has become possible to make in-situ measurements of the composition of residual cloud particles using single particle mass spectrometry. Through these measurements, one can determine which particle sources and compositions are most commonly involved in cloud formation. This presentation will focus on in-situ single particle mass spectrometry measurements of cloud residual composition made during two aircraft campaigns, CalWater and ICE-T, designed to better understand the composition of ice nuclei in mixed phase clouds. The impact of different particle sources on cloud microphysics and precipitation processes will be discussed. The role of long range transported dust and bioparticles on precipitation processes occurring over California will be described.