Attempt at Ship-Based Observations of Oceanic Drop Size Distributions Over the Tropical Warm Pool

Abstract

Drop size distributions (DSDs) obtained over ocean in the tropical warm pool using a shipboard optical disdrometer are investigated. Quality control procedures, including the suppression of effects primarily related to the ship-relative wind, are applied to extract reliable data. The procedures suppressed the number of data points to 2% of the total rain duration. The characteristics of the obtained DSD parameters such as averaged size and intercept parameter are reasonably consistent with those of previous studies, with the larger size for a specific rain rate. The categorization of the data according to precipitation characteristics contrasts the DSD parameters, especially for the stratiform precipitation over the coastal ocean prior to the MJO active period. This precipitation is also an outlier when the obtained DSDs are applied to the scattering simulation for the radar-based quantitative precipitation estimation, while the contrast between the open ocean and the coastal ocean is not clearly separated.