Synoptic Performance Characteristics of the Two-Level Atmospheric Model.

This analysis of the two-level atmospheric model compares daily changes during January from three experiments and five years of observed data for surface air temperatures at Columbia, Missouri, and five basic characteristics in the vicinity of the Icelandic and Aleutian Lows. Strong diurnal changes were found in all simulated temperatures, but low and high diurnal ranges that would accompany specific synoptic events in nature are not well portrayed. The positions of the lows tested based on the lowest daily pressures were clumped, and in the North Atlantic were located southwest of the climatological center. Mean January pressures from these centers showed that the simulated Icelandic Low is 4.3 mb less intense, while the Aleutian Low is 1.9 mb more intense than observed. When all analyzed low pressure centers were combined, simulated speeds were slower and durations longer than observed. Finally, the simulated tracks were shown to be farther north. 29 pp. Ref.