Convection and Rainfall off the Pacific Coast of Colombia using OTREC field campaign

Le résumé fourni par la source

We use observations from OTREC2019 (Organization of Tropical East Pacific Convection) field project to study the characteristics of mesoscale convective systems (MCSs) off the Pacific Coast of Colombia. The high-altitude dropsondes were deployed in a grid pattern to map out the state of the atmosphere from the National Science Foundation/National Center for Atmospheric Research Gulfstream V aircraft. In addition, the downward-pointing Hiaper cloud radar observed patterns and types of precipitation produced by the convection.From reflectivity and fall speed in radar observations, we find that some convection produced mainly aggregates of ice crystals above the freezing level whereas others were dominated by graupel particles. MCSs dominated by ice crystal aggregates above the freezing level are generally thought to indicate decaying stratiform rain systems with only light rain. However, dropsonde grids showed a broader range of MCS types in this category, some with shallow convection producing intense rainfall.We conclude that the radar had difficulty in distinguishing between different types of aggregate-dominated MCSs which is a problem because satellite borne radars would likely have the same issue.

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