摘要：We simulated a marine stratus deck sampled during the Marine Stratus/Stratocumulus
Experiment (MASE) with a three-dimensional large eddy simulation (LES) model at
different model resolutions. Various characteristics of the vertical velocity from the model
simulations were evaluated against those derived from the corresponding aircraft in situ
observations, focusing on standard deviation, skewness, kurtosis, probability density
function (PDF), power spectrum, and structure function. Our results show that although
the LES model captures reasonably well the lower-order moments (e.g., horizontal averages
and standard deviations), it fails to simulate many aspects of the higher-order moments,
such as kurtosis, especially near cloud base and cloud top. Further investigations of
the PDFs, power spectra, and structure functions reveal that compared to the
observations, the model generally underestimates relatively strong variations on small
scales. The results also suggest that increasing the model resolutions improves the
agreements between the model results and the observations in virtually all of the
properties that we examined. Furthermore, the results indicate that a vertical grid size
<10 m is necessary for accurately simulating even the standard-deviation profile, posing new
challenges to computer resources.
