This proposal focuses on understanding diapycnal upwelling in the eastern equatorial pacific using autonomous drifters

The National Oceanic and Atmospheric Administration (NOAA) awarded Scripps Institution of Oceanography a $750,000 Project Grant under the Climate and Atmospheric Research program (CFDA 11.431) effective September 1, 2025, through August 31, 2028. The project delivers advanced oceanographic observational data and analysis to improve understanding of diapycnal upwelling and mixing processes in the eastern equatorial Pacific Ocean. Specifically, the award funds deployment of three WireWalkers and three profiling floats equipped with microstructure turbulence sensors to measure turbulent dissipation rates and estimate vertical heat and buoyancy fluxes across the Cold Tongue and equatorial undercurrent regions. This observational infrastructure generates a continuous data stream on ocean mixing dynamics, air-sea interactions, and biological-chemical influences on equatorial upwelling that directly support enhanced predictive models of equatorial Pacific dynamics and improved El Niño onset prediction capabilities.

The project outputs include open-access datasets on turbulence characteristics and vertical heat-buoyancy fluxes, scientific analyses addressing priority research gaps identified in the TEPEX-E (Tropical Pacific Observing System 2000 – Equatorial Pacific) Science Plan, and modeling improvements to support NOAA's long-term climate prediction and hazard mitigation objectives. By advancing fundamental understanding of processes driving equatorial Pacific climate variability, the research strengthens NOAA's capacity to provide timely, science-based information to states and communities for climate preparedness and resilience planning. The award emphasizes diversity-driven outreach and public data accessibility as integral components of project delivery.

Diapycnal mixing and upwelling play critical roles in the regions heat, nutrient, and energy dynamics, influencing large-scale ocean circulation and climate variability, particularly in the context of enso events. Predicting the onset of EL nino remains a significant challenge, particularly in the context of long-term changes in enso behavior due to climate change. This unpredictability complicates long-terms noaas efforts to help mitigate the impacts on human populations, underscoring the urgency of advancing our understanding of these critical climate processes. The present proposal leverage state-of-the-art platforms and sensors to collect information on the sea surface temperature sensitivity to deep cycle turbulence, helping tepex-e community to create a continuum of observation of buoyancy and heat fluxes and provide elements of answers to three of the four scientific problems described in the section cold tongue mixing and coupling to the atmosphere described in the tepex-e science plan namely, (a) ocean mixing, (b) airsea sea interaction and the mabl and (d) influence of biology and chemistry in the equatorial upwelling. We propose to deploy three wirewalkers and three profiling float equipped with microstructure turbulence sensors. The autonomous drifters can measure turbulent dissipation rates and provide estimates of the vertical heat and buoyancy fluxes. An array of assets can be deployed to observe the meridional extent of the deep cycle turbulence across the cold tongue and northern flank of the equatorial undercurrent (EUC). Data collected will improve our understanding of the processes driving diapycnal upwelling and enhance predictive models of equatorial pacific dynamics. Furthermore, the project emphasizes open-access data sharing and diversity-driven outreach, integrating advanced scientific objectives with societal impact initiatives.