Atmospheric Cold Pools in the Bay of Bengal: A Fuzzy Logic Approach

Jared Buckley, University of Massachusetts Dartmouth, Dartmouth, MA, United States and Amit Tandon, University of Massachusetts, Dartmouth, Mechanical Engineering, Dartmouth, MA, United States
Atmospheric cold pools occur when anomalous dense air descends to the surface after being cooled by the evaporation of precipitation. Cold pools have been implicated in the aggregation of convective systems, leading to a need for more observations of their size, strength, frequency, and duration over the tropical oceans. Using observations from a WHOI mooring and two OMNI (Ocean Moored Buoy Network for northern Indian Ocean) moorings in the northern Bay of Bengal, we use a new fuzzy logic framework to objectively identify cold pools, analyze their properties, and determine their size distribution. Designed to compensate for the vagueness in defining thresholds for cold pools in air temperature time series, our framework moves beyond the strict binary cold-pool-or-not-cold-pool viewpoint by permitting the inclusion of partial cold pools. Our results reveal that cold pools occur frequently in the northern Bay of Bengal, with their size and duration following a lognormal distribution.