J6J. 3 THE STRUCTURE AND EVOLUTION OF THE DRYLINE AND SURROUNDING BOUNDARY LAYER ON 22 MAY 2002 DURING IHOP

摘要: Surface boundaries such as fronts (eg Carbone 1982; Nielsen and Nielley 1990), sea-breezes (eg Laird et al 1995; Kingsmill 1995), and thunderstorm outflows (eg Wakimoto 1982; Mahoney 1988) play an important role in the initiation of deep convection, and thus have been extensively studied. The dryline has also become a subject of increasing interest due to its frequent association with convection initiation (CI) and subsequent development of severe weather (Rhea 1966; Bluestein and Parker 1993). During the Verification of the Origins of Rotation in Tornadoes Experiment or VORTEX (Rasmussen et al 1994), the structure of the dryline was observed in several cases (Atkins et al 1998; Ziegler and Rasmussen 1998; Weiss and Bluestein 2002). Results from these experiments have improved the conceptual model of dryline morphology, though details of the temporal and spatial variability needed to predict convection initiation processes are lacking. Although we have a fairly good understanding of the mesoscale conditions favor storm development, a lack of high resolution observations in many previous studies has precluded an examination of the very small, kilometer-scale processes which force CI (Johns and Doswell 1992; McNulty 1995).