32nd Conference on Broadcast Meteorology/31st Conference on Radar Meteorology/Fifth Conference on Coastal Atmospheric and Oceanic Prediction and Processes

Monday, 11 August 2003
Fine-scale radar observations of a dryline during the International H2O Project
Christopher C. Weiss, University of Oklahoma, Norman, OK; and H. B. Bluestein and A. L. Pazmany
Poster PDF (184.4 kB)
The southern Plains dryline has long been identified as a location favorable for the development of deep moist convection. Thunderstorms initiated along the dryline often are in an environment conducive for the attainment of supercell characteristics, with the attendant threat of large hail, damaging winds and tornadoes. Although progress has been made in our understanding of the dryline, the kinematic structure of the boundary is still unclear. Any consistent success in the prediction of convective initiation on the dryline relies on the precise determination of all scales of motion, particularly in the dryline convergence zone (DCZ) where parcels must ascend to the level of free convection (LFC) for initiation to occur.

During the spring of 2002, the International H2O Project (IHOP) sought to resolve the kinematics of the dryline interface, particularly in the context of convective initiation. Ground-based (e.g., S-Pol, SMART-Radar, DOWs) and airborne-based (e.g., ELDORA) radar platforms accomplished this data collection. On May 22, 2002, in conjunction with these platforms, the 3-mm wavelength mobile radar from the University of Massachusetts at Amherst obtained very-high resolution RHI data cutting across a dryline in the eastern Oklahoma panhandle. The very narrow beamwidth (0.18 deg) of the antenna permitted very fine scale measurements across the dryline boundary, with vertical and range resolutions of 5 m and 30 m, respectively, at a distance 1 km from the vehicle.

The first portion of the paper will briefly consider different variational techniques for the synthesis of three-dimensional velocity vectors from multiple radar measurements of radial velocity. An Observation System Simulation Experiment (OSSE) will be presented to exhibit and verify these techniques. Composite observational analyses from all the aforementioned IHOP radar platforms will be presented in the remainder of the paper, utilizing the variational methods discussed earlier.

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