Tag: PHOD_Publication

Projections of faster onset and slower decay of El Niño in the 21st century

Lopez, H., Lee, S. K., Kim, D., Wittenberg, A., & Yeh, S. W. (2021). Projected Increase in Fast-Growing and Slow-Dissipating El Niño Events in the 21st Century.

Abstract: Future changes in the seasonal evolution of El Niño – Southern Oscillation (ENSO) during the onset and decay phases have received little attention by the research community. This work investigates the projected changes in the spatio-temporal evolution of El Niño events in the 21st Century (21C) using a large ensemble simulation of a couple general circulation model under anthropogenic forcing. Here we show that El Niño is projected to (1) initiate sooner in boreal spring, (2) to grow at a faster rate, (3) to persist longer over the eastern and far eastern Pacific, and (4) to have a broader impact on remote teleconnections. Significant changes in the tropical Pacific mean state, dominant feedback processes, and a projected increase in stochastic westerly wind burst forcing largely explain the fast growing and slow dissipating El Niño in the late 21C. Important implications of these findings are that the global climate impacts are projected to become more significant and persistent, owing to the extended persistence of El Niño.

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Remote Impact of the Equatorial Pacific on Florida Current Transport

Dong, S., Volkov, D. L., Goni, G., Pujiana, K., Tagklis, F., & Baringer, M. (2022). Remote Impact of the Equatorial Pacific on Florida Current Transport. Geophysical Research Letters, e2021GL096944.

Using in-situ and satellite observations, this study is the first to demonstrate that ENSO temperature anomalies in the equatorial Pacific force Florida Current transport (FCT) anomalies 3 months later.  The connection between FCT and ENSO is through ENSO’s impact on sea level on the eastern side of the Florida Straits, which is associated with anomalous oceanic convergence/divergence in the Caribbean region and the Bahamas forced by ENSO-induced wind stress curl changes. This established relationship gives some predictability of the Florida Current transport and coastal sea level changes with a 3-month lead time, which can benefit coastal communities, particularly during strong El Niño and La Niña events.

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Frontiers in Ocean Observing

Kappel, E.S., S.K. Juniper, S. Seeyave, E. Smith, and M. Visbeck, eds. 2021. Frontiers in Ocean Observing: Documenting Ecosystems, Understanding Environmental Changes, Forecasting Hazards. A Supplement to Oceanography 34(4), 102 pp., https://doi.org/10.5670/oceanog.2021.supplement.02.

Articles in this inaugural Frontiers in Ocean Observing supplement to Oceanography describe new technologies and reveal some exciting results that advance our understanding of the world ocean and its resources and support its sustainable use and management. Topics covered align with the priorities of the UN Decade of Ocean Science for Sustainable Development (2021–2030). Five articles in this Supplement were co-authored by AOML scientists and science support personnel: Climate-Relevant Ocean Transport Measurements in the Atlantic and Arctic Oceans, Monitoring Boundary Currents Using Ocean Observing Infrastructure, An Integrated Observing Effort for Sargassum Monitoring and Warning in the Caribbean Sea, Tropical Atlantic, and Gulf of Mexico, Uncrewed Ocean Gliders and Saildrones Support Hurricane Forecasting and Research, and The Technological, Scientific, and Sociological Revolution of Global Subsurface Ocean Observing.

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Revisiting the Recharge and Discharge Processes for Different Flavors of El Niño

Chakravorty, S., Perez, R. C., Gnanaseelan, C., & Anderson, B. T. (2021). Revisiting the recharge and discharge processes for different flavors of El Niño. Journal of Geophysical Research: Oceans, 126(11), e2020JC017075.

Plain Language Summary: The El Niño-Southern Oscillation (ENSO) is the largest source of year-to-year climate variability. ENSO has a pronounced influence on regional and global circulation and precipitation patterns and thus has considerable worldwide socio-economical impacts. El Niño, the warm phase of ENSO, exhibits modulation in the longitudinal location of its maximum warming, creating what is referred to as ENSO diversity. For conventional El Niño events, maximum surface warming is located in the eastern equatorial Pacific, for which subsurface warming along the tropical Pacific has proven to serve as a predictor several months in advance. Previous studies disagree on whether this subsurface warming is similarly essential for El Niño events that have peak surface warming in the central Pacific. The authors developed an improved method for identifying these two types of El Niño in an ocean reanalysis product. Using this improved method, they found no clear evidence of a subsurface warming precursor for the central Pacific El Niño events along the equator. This lack of a tropical subsurface precursor limits our ability to predict these types of El Niño events.

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Observed Ocean Bottom Temperature Variability at Four Sites in the Northwestern Argentine Basin: Evidence of Decadal Deep/Abyssal Warming Amidst Hourly to Interannual Variability During 2009–2019

Meinen, C. S., Perez, R. C., Dong, S., Piola, A. R., & Campos, E. (2020). Observed ocean bottom temperature variability at four sites in the northwestern Argentine Basin: Evidence of decadal deep/abyssal warming amidst hourly to interannual variability during 2009‐2019. Geophysical Research Letters, e2020GL089093.

Consecutive multiyear records of hourly ocean bottom temperature measurements are merged to produce new decade‐long time series at four depths ranging from 1,360 to 4,757 m within the northwest Argentine Basin at 34.5°S. Energetic temperature variations are found at a wide range of time scales. All sites exhibit fairly linear warming trends of approximately 0.02–0.04°C per decade over the period 2009–2019, although the trends are only statistically different from zero at the two deepest sites at depths of ~4,500–4,800 m. Near‐bottom temperatures from independent conductivity‐temperature‐depth profiles collected at these same locations every 6–24 months over the same decade…

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Mechanisms of Eddy-Driven Variability of the Florida Current

Domingues, R. M., Johns, W. E., & Meinen, C. S. (2019). Mechanisms of Eddy-Driven Variability of the Florida Current. Journal of Physical Oceanography, 49(5), 1319-1338.

Abstract: In this study, mechanisms causing year-to-year changes in the Florida Current seasonality are investigated using controlled realistic numerical experiments designed to isolate the western boundary responses to westward propagating open ocean signals. The experiments reveal two distinct processes by which westward propagating signals can modulate the phase of the Florida Current variability, which we refer to as the “direct” and “indirect” response mechanisms. The direct response mechanism involves a two-stage response to open ocean anticyclonic eddies characterized by the direct influence of Rossby-wave barotropic anomalies, and baroclinic wall-jets that propagate through Northwest Providence Channel…

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