Recent numerical work has resolved the sensitivity of dryline structure to variations in surface characteristics (e.g., terrain slope, land-use gradients). In this investigation we will attempt to expand on this work by creating a triple-point regime in which we simulate the influence of a cold pool on the transverse dryline secondary circulation. Recent observational work using airborne pseudo-dual Doppler analyses has revealed the presence of a “residual dryline secondary circulation” (RDSC) to the north of a pre-existing east-west outflow boundary as the individual thermodynamic and kinematic environments to either side of the dryline are advected up and over the cold pool.
Two-dimensional simulations of the Advanced Regional Prediction System (ARPS) have captured the pertinent features of the dryline (e.g., the structure, motion and sensitivity of the virtual potential temperature gradient and secondary circulation). Future work will involve the addition of a thunderstorm-generated cold pool. These three-dimensional results will be presented at the conference.
Reference:
Peckham, S. E., and L. J. Wicker, 2000: The influence of topography and lower-tropospheric winds on dryline morphology. Mon. Wea. Rev., 128, 2165-2189.
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