Abstract
Organization metrics were originally developed to measure how densely
convective clouds are arranged at mesoscales. In this work, we apply
organization metrics to describe tropical synoptic scale convective
activity. Such activity is identified by cloud-precipitation (hybrid)
regimes defined at 1-degree and 1-hourly resolution. Existing metrics
were found to perform inadequately for such convective regime aggregates
because the large domain size and co-existence of sparse aggregate
occurrences with noisy isolated convection often violate assumptions
inherent in these metrics. In order to capture these characteristics,
the existing “convective organization potential” (COP) metric was
modified so as to: (1) focus on local organization and (2) provide
increased weight to aggregate size. The resulting “area-based COP”
(ABCOP) is found to outperform existing metrics in tropical convective
events at synoptic scales. Moreover, this new organization metric can
match the performance of existing metrics, or arguably be better, over a
wide range of domain sizes.