Clouds and water vapor are both the product and driver of the motions in the atmosphere. They are also key ingradients in the interaction between the atmosphere and other components of the climate system. What determines the amount and distribution of clouds and water vapor in the atmosphere? What is their relatitonship with precipiation? What's their role in climate variability? How will they respond to anthropogenic forcing? These are some sample questions concerning the climatic role of water vapor and clouds that I am trying to address through analyzing observational data and modeling.
Because the close association with small-scale motions in the atmopshere--bounday layer turbulence and moist convection, clouds and water vapor are difficult to simulate by climate models. Cloud feedbacks are considered as a major uncertainty in climate models by IPCC. The realism of water vapor feedback in climate models is also subject to debate. The spatial distribution and temporal variability of rainfall and snow simulated by climate models is not yet adequately realistic, casting doubt on their predictions/projections of droughts and other climate phenomena that cause large-scale disruption to our wellbeing. How to better represent the effects of water vapor and clouds in climate models is also an issue that I am concerned with.
Water vapor and clouds are components of a larger picture--the earth's hydrological cycle. Addressing how the atmospheric hydrological cycle responds to anthropogenic forcing is a long-term goal of my research.