Earth's clouds are critical for weather and climate. Cloud formation in earth and other planetary atmospheres is a deceptively simple physical process of condensation. And yet clouds are very challenging to understand and predict due to the interplay of clouds with their environment. Cloud physics spans 12 orders of magnitude in space from the micro-scale of cloud drops to the planetary scale of the general circulation and a similar order of magnitude in time from fractions of a second of cloud drop collisions to centennial climate time scales. Variability across these scales is one of the key reasons for the complexity of cloud physics and the difficulty in practically simulating clouds for predicting weather and climate. This presentation will dive into the interplay of cloud physics at the micro-scale of the evolution of drops and crystals, to the turbulent 'macro scale' of the dynamics of clouds, to the effect of clouds on radiative transfer and climate. This framework for understanding the complexity of clouds and how they are observed and simulated to help us understand weather and climate and constrain key uncertainties in earth system prediction. Key issues in cloud physics include the response of clouds to changes in their environment due to climate change, the interplay of aerosol particulates with clouds, and the additional complexity of the metastable 'mixed phase' regime where ice and liquid may be present. Clouds on other bodies in the solar system will also be discussed. Decades of cloud research have taught us a lot, and left a lot of questions. We are slowly now uncovering answers with new data, new observations and new techniques.
a joint institute of 
and 
and