Walter Orr Roberts Lecture
This paper, as the written version of the 1995 AMS Walter Orr Roberts Lecture, provides an overview of the current status of the inclusion of land surface processes in climate models. These processes provide fluxes of water and energy to atmospheric models and help determine surface meteorology and climate over the continents. With the increasing complexity and importance of these parameterizations and their detailed treatments of the roles of soils and vegetation have come greater demands for observational programs to evaluate their success and to provide required parameters. Intercomparisons between different land models are also becoming increasingly valuable as a means of identifying their weaknesses and limitations. The paper especially highlights the need for further emphasis on the coupling between land and the atmosphere in models. In particular, it calls for further evolution and improvement of the model treatments of precipitation, cloud effects on surface radiation, and boundary layer processes.