HR: 10:20h
AN: AE32A-01 INVITED     [Abstracts]
TI: Relationships Among Electrification, Lightning, Kinematics, and Microphysics: Lessons From the Interaction of Observations and Numerical Storm Simulations
AU: * MacGorman, D R
EM: don.macgorman@noaa.gov
AF: NOAA/National Severe Storms Laboratory, 1313 Halley Cir., Norman, OK 73069 United States
AB: Observations and numerical storm simulations each have a role in teaching us more about the relationships among electrification, lightning, kinematics, and microphysics. Observations depict aspects of reality, but often sample with too little temporal or spatial resolution or have too many voids to test particular concepts and relationships. Furthermore, many properties critical to developing our knowledge of relationships either must be inferred indirectly from observations or cannot be observed at all. Numerical storm simulations fill this shortcoming of observations by providing a complete, physically consistent set of storm parameters with which to determine relationships. However, numerical simulations may not accurately mimic real behavior, because of shortcomings in their parameterizations or physics. Thus, numerical storm simulations must be tested against observations, and their parameterizations or physics must be refined as needed to mimic the investigated behaviors more realistically. One example in which the interaction of observations and simulations was critical was in determining that the noninductive exchange of charge between ice particles and actively riming graupel is able to produce thunderstorm electric field magnitudes capable of initiating lightning and to produce electrical storm structure similar in key respects to observed electrical structure. More recently observations and simulations have shown that lightning flash rates are roughly proportional to graupel mass or volume and to updraft mass flux or updraft volume, as one might expect from the noninductive mechanism. Furthermore, recent observations suggest strongly that the polarity of thunderstorm electrical structure is sometimes inverted from the polarity usually observed in storms, and simulation studies have recently begun examining why this occurs. However, our understanding of underlying storm properties and processes needs to be improved to address some storm relationships in simulations. Underlying uncertainties include the extent to which inductive processes can contribute to electrification (which, in turn, depends on collision/rebound probabilities and other microphysical properties), the distribution of ice particle concentrations, and the behavior of noninductive charge exchange at small liquid water contents.
DE: 3304 Atmospheric electricity
DE: 3314 Convective processes
DE: 3324 Lightning
DE: 3333 Model calibration (1846)
DE: 3360 Remote sensing
SC: Atmospheric and Space Electricity [AE]
MN: Fall Meeting 2005