Impact of microphysical parameterizations on simulated storm evolution and remotely-sensed characteristics
Abstract
A non-hydrostatic, three-dimensional cloud model was used in conjunction with
a radiative transfer model to study the sensitivity o f the model-simulated storms and
their remotely-sensed characteristics to the microphysical parameterizations used in the
cloud model. Understanding the sensitivity o f the cloud-radiation databases to the
assumptions that went into their building is o f particular importance since such cloudradiation
databases are extensively used in the development o f algorithms for retrieval o f
rainfall and latent heating from microwave observations o f precipitating systems. This
study was conducted with the intent to shed more light on how the microphysical
parameter choices affect not just a particular storm characteristic but the storm's microand
macro-structure and evolution.
Three types o f sensitivity tests were performed. The first evaluated sensitivity
to the choice o f microphysical parameterization scheme. For that purpose tw o
microphysical schemes were compared - Tao's and Perrier's. Both schemes share the parameterizations. Their main differences are in the treatment of the cloud ice initiation
processes and the subsequent growth of snow. The second test evaluated the sensitivity
of modeled storms to the selection of ice aggregation parameters and to the assumed
number of ice crystals that are activated at 0° C. The third test evaluated the sensitivity
of simulated storms to the selection of the hydrometeor’s descriptive parameters
(density, terminal velocity, and particle size distributions).
The storm dynamics and remotely—sensed characteristics are affected by the
microphysical parameterization philosophies and by the choice of microphysical
parameters and hydrometeor descriptive parameters. Different storm characteristics
show sensitivity to different microphysical assumptions. This rinding suggests that by
using coincidental observations of a variety of storm characteristics it would be possible
to discriminate between simulations and to determine what microphysical setup
produces storms that compare best to observations. Being able to reproduce the storm in
its entirety will indicate that the complex intercorrelations between the different
processes and scales are, indeed, properly represented by the model. This in turn, will
give a high fidelity in the rainfall and latent heating retrieval algorithms using cloud model databases.
Subject
Atmospheric SciencesCollections
Citation
Hristova-Veleva, Svetla M. (2000). Impact of microphysical parameterizations on simulated storm evolution and remotely-sensed characteristics. Available electronically from https : / /hdl .handle .net /1969 .1 /152150.