For 26 days in mid‐June and July 2000, a research group comprised of U.S. Navy, NASA, and university scientists conducted the Puerto Rico Dust Experiment (PRIDE). In this paper we give a brief overview of mean meteorological conditions during the study. We focus on our findings on African dust transported into the Caribbean utilizing a Navajo aircraft and AERONET Sun photometer data. During the study midvisible aerosol optical thickness (AOT) in Puerto Rico averaged 0.25, with a maximum >0.5 and with clean marine periods of ∼0.08. Dust AOTs near the coast of Africa (Cape Verde Islands and Dakar) averaged ∼0.4, 30% less than previous years. By analyzing dust vertical profiles in addition to supplemental meteorology and MPLNET lidar data we found that dust transport cannot be easily categorized into any particular conceptual model. Toward the end of the study period, the vertical distribution of dust was similar to the commonly assumed Saharan Air Layer (SAL) transport. During the early periods of the study, dust had the highest concentrations in the marine and convective boundary layers with only a weak dust layer in the SAL being present, a state usually associated with wintertime transport patterns. We corroborate the findings of Maring et al. [2003] that in most cases, there was an unexpected lack of vertical stratification of dust particle size. We systematically analyze processes that may impact dust vertical distribution and speculate that dust vertical distribution predominately influenced by flow patterns over Africa and differential advection coupled with fair weather cloud entrainment, mixing by easterly waves, and regional subsidence.

As part of Puerto Rico Dust Experiment (PRIDE), a Piper Navajo research aircraft, equipped with particle probes and an airborne Sun photometer, was deployed to Puerto Rico in July 2000. During the study, mid‐visible optical depths in Puerto Rico due to dust reached 0.5. In the middle of the summer transport season, the vertical distributions of dust were similar to that commonly assumed in the region with dust concentrated in the Saharan Air Layer (SAL) aloft. However, during the first half of the study period, dust had the highest concentrations in the marine and convective boundary layers, with lower dust concentrations above the trade inversion despite the presence of a strong SAL. Supporting meteorology suggests that the state of the monsoon on the coast of Africa influences the nature of the vertical distribution of dust in the Caribbean.