An Investigation of Multiple Classifications of Clouds Over Mid-latitude
Cyclones
Abstract
Extratropical cyclones are the primary source of precipitation in the
mid-latitudes. The physical mechanisms that drive cyclones are well
understood, and a variety of studies have demonstrated strong
relationships between cloud structures and cyclone dynamics. However,
past research has focused on simplistic cloud categorizations, which
lack spatial and textural information that is included in more
sophisticated classification schemes. Unsupervised deep learning
approaches may have significant advantages over these past methods,
allowing them to discover previously unidentified cloud information in
large datasets. One such approach is the rotation-invariant cloud
clustering (RICC), which combines a dimensionality reduction deep
learning technique with rotation-invariant clustering of input cloud
images. We employ the RICC, along with two established cloud clusters,
to investigate the relationship between extratropical cyclones and
horizontal cloud distributions. We focus on comparing these different
sets of clusters to each other. First the spatial distributions and the
physical properties of the identified cloud types are examined around
cyclones and the results corresponding to each classification are
compared in detail. Then the similarities of these distributions are
quantified using structural similarity. Additionally, the evolution of
spatial distributions of cloud over the lifetime of cyclones is compared
between the different classifications. Interestingly, we identify the
same broad physical developments in all sets of clusters. Notably,
identified differences are likely due to differences in measurement
processes and resolutions of the corresponding datasets.