RAPID: Upper-Air Observations over the Far Eastern Pacific (OTREC; ChocoJEX II)

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This award supports work on the Organization of Tropical East Pacific Convection (OTREC) field campaign. The campaign seeks to understand the formation and development of tropical convective clouds and associated heavy rainfall in the adjacent but distinct regions of the eastern equatorial Pacific and the southwest Caribbean, along with their evolution over the intervening portions of Central America and Colombia. The campaign also examines the genesis and evolution of easterly waves, large westward-moving atmospheric disturbances (wavelengths of about 2,000 km) which occur on a weekly basis in the Caribbean and eastern Pacific. The full set of campaign awards is discoverable on the nsf.gov/awardsearch webpage by a keyword search on "OTREC".Work supported under this award contributes to the campaign by adding a weather station in a region of interest. The station provides continuous surface observations (winds, pressure, temperature, etc) as well as weather balloon launches to record vertical profiles of atmospheric conditions. It is located at Nuqui (6N, 77W), on the west coast of Colombia. The site is chosen for its proximity to the Choco' jet, a low-level jet flowing northward over Choco' Province, which extends from the Serrania del Baudo', the western fork of the Andes in Colombia, to the Pacific coast.The jet is of interest to OTREC because it extends significantly offshore and may contribute substantially to rainfall in the OTREC study area. It may also play a key role in the generation of easterly waves. The PIs hypothesize that the diurnal cycle of heating and cooling over the western slopes of the Andes accounts for the diurnal cycle of offshore convection, despite differences in timing. They also argue that the Andean topography plays a role in organizing the rain-bearing mesoscale convective systems found over Choco' Province and the adjacent ocean.The Nuqui station will operate through August and September, with balloon launches four times per day when the OTREC aircraft is collecting data over the eastern Pacific (see OTREC award 1758513). The station is also complementary to rainwater sampling under OTREC award 1759255, for which Nuqui is one of three collection sites. The project is also a follow-on to ChocoJex, a Colombian-led field campaign focused specifically on the Choco' jet.A better understanding of extreme precipitation and its relationship to low-level jets is desirable for societal as well as scientific reasons. Research under this award directly addresses these issues, with a particular focus on hazardous mesoscale convective systems. The work also addresses easterly waves, which can spawn destructive hurricanes. In addition, the award supports a partnership between US and Colombian scientists and thus promotes capacity building in the international research enterprise.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.