About my research

My research interests guide those of the Atmosphere in the Earth System department which I lead.  Rather than maintaining my own separate research group I prefer to work on projects with scientists in the department's different working groups.  For instance, I have been working with scientists in the observations and process studies  group to understand what determines the macroscopic properties of clouds in the tradewinds, these interests have lead us to deploy state of the art remote sensing instruments on the island of Barbados.  With PhD students and scientists in the global modeling group I am working toward developing a better understanding of the distribution of deep tropical convection; and joint with the middle and upper atmosphere group we have begun to explore how changes to the planetary albedo affect the climate system.

 

The questions my research attempts to answer broadly reflects my overarching interests in clouds — dispersions of condensate in a turbulent flow.  Examples of specific questions e are interested in answering include:

  • How do clouds work and what determines their aggregate behavior?
  • How do they help set large-scale circulations, or mediate interactions
    among other components of the Earth System?
  • How might they change in the future, how different were they in the past?

 

The patterning of clouds depends on their regimes, as do their effects.  For instance, stratocumulus prevail in regions where the cold upwelling ocean confronts the warm downwelling atmosphere, such as in the eastern boundary current regions of the subtropical gyres. The stratocumulus in these climate zones have a dramatic impact on the energy balance of the earth system; their thin veil (sometimes only 100m thick) extends for thousands of kilometers over otherwise dark oceans, which they cool.  Similar clouds are apparent in the arctic, where they are thought to insulate the ice caps. Shallow cumulus convection in the trades are arguably the most prevalent cloud type on the planet and their dynamics are decisive in determining the surface evaporation over the world ocean, thereby driving ocean circulations while helping to charge the atmosphere in anticipation of the deep convective towers that, in turn, precipitate this vapor (as condensate) back to the surface. The statistics and structure of deep precipitating convection is critical to determining the character of the hydrological cycle and hence the nature of the atmosphere's interaction with the land surface. 

Using a variety of methodologies I am interested in understanding these and other cloud regimes so as to better understand basic character of the climate system and its susceptibility to change.