Numerical simulations of the interactions between tropspheric aerosols and clouds are being conducted. One goal is to determine if the indirect effects of aerosols on clouds is a significant feature of Earth's climate system. Another goal is to simulate the life cycle of tropospheric aerosols and clouds in detail. To date these simulations have focused on microphysics, and only treated one spatial dimension. This past year saw the development of a three dimensional large eddy simulation model including detailed microphysics. The eventual goal is to be able to model tropospheric aerosols, marine boundary layer clouds and cirrus clouds including three dimensional dynamics, atmospheric chemistry, and detailed microphysics. This work is supported by NASA, and the Navy. This research group, led by Dr. Brian Toon, also has been selected for an EOS Interdisciplinary Investigator effort to treat aerosol effects on global climate using the NCAR Community Climate Model, and ither appropriate general circulation models. The group is collaborating with Dr. Andy Ackerman of NASA's Ames Research Center on marine stratus models. Graduate students are laying many roles in this research: Ms. Ana Lia Quijano has begun a study of the evolution of the optical properties of desert dust; Mr. Peter Colarco has begun a study of the three dimensional distribution of aerosols in the earth's troposphere; Ms. Kari Klein is currently investigating the formation of new particles in the upper atmosphere and is participating in a field program in the Indian Ocean to obtain more data on this subject; Ms. Brandy Gamblin is developing a model of homogeneous air chemistry to be used in developing a global model of chemically reactive aerosols.
