This volume contains refereed papers submitted by international experts who participated in the Atmospheric Modeling workshop March 15 -19, 2000 at the Institute for Mathematics and Its Applications (IMA) at the University of Minnesota. The papers cover a wide range of topics presented in the workshop. In particular, mathematical topics include a performance comparison of operator-splitting and non- splitting methods, time-stepping methods to preserve positivity and consideration of multiple timescale issues in the modeling of atmospheric chemistry, a fully 3D adaptive-grid method, impact of...