Arranging 3 years’ worth of airborne precipitation particle images to
construct a precipitation particle image dataset in Shan⁃ dong Province.
Building a precipitation particle recognition model based on EfficientNet
convolutional neural network, named PREN (Precipitation particle Recognition
model based on EfficientNet convolutional neural Network).The accuracy rate is
98%, and the multimodel and multi-index evaluation and comparison
experiments verify that PREN demonstrates excellent robustness and
generalization ability. Taking typical stratiform-cumulus mixed cloud
precipitation as two examples (total 3 time periods), PREN is applied to the
par⁃ ticle characteristics
analysis of generating cells. Combined with airborne Ka-band cloud radar
and DMT particle measurement system, an analysis conducted on the shape
proportion of precipitation particles inside and outside the generating cells
and indifferent intensity generating cells, revealing the precipitation
mechanism. The results show that the shapes of precipitation particles in the
generating cells are mainly spherical, needle-like, irregular and
columnar. Precipitation particles outside the generating cells are mostly
spherical and needle-like. The cloud microphysical parameters in the generating cells with
different intensities vary. The proportion of graupel and needle particles in
the precipitation maturity stage is higher than that in the dissipation stage.
The average chord length of precipi⁃ tation particles in the maturity stage is 415 µm. While
the average chord length of particles in dissipation stage is 367 µm. The par⁃ ticles on the top of
generating cells are mainly spherical and hexagonal, primarily growing through
the process of deposition. The ratio of irregular particles and columnar
particles in the 0 ℃ are increasing, and the melting process and dynamic
conditions favor aggregation and growth, forming irregular particles, while
columns mainly originate from the upper levels of the atmosphere.