Tag: PHOD_Publication

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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