Examinando por Autor "Valle-Levinson, Arnoldo"

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    Tidal and residual dynamics in an Inland Sea fjord system
    (Journal of Marine Systems, 2026-07) Higueras Sepúlveda, Joan Manuel; Cáceres, Mario A.; Valle-Levinson, Arnoldo
    Velocity measurements were collected to characterize the transverse flow structure of five across-channel circuits in the inland sea of Northern Chilean Patagonia. Current profiles were recorded with an Acoustic Doppler Current Profiler (ADCP) during repeated transects in each circuit, spanning a semidiurnal tidal cycle. Tidal current amplitudes increased southward as cross-sections became narrower and shallower. An analytical model adequately replicated the main features of tidal currents in three frictionally dominated transects in the Huemules and Quesahuén circuits. The observed residual flow patterns in the northern circuits varied from a twolayer quasi-geostrophic pattern in the Moraleda-Refugio and Del Medio passage to a three-layer pattern in Moraleda-Tuap, and to a laterally sheared pattern in southern circuits (Huemules and Quesahuén). The observed patterns showed similarities to other estuaries, but in fjords a three-layer residual flow is more common due to greater depth. A southward decrease in Kelvin (Ke) and Richardson (Ri) numbers suggested more influence of rotational effects and stratification in the northern transects, whereas a southward increase of the Ekman number (Ek) suggested an enhancement of frictional effects in the southern circuits. Across-channel dynamic balance in northern circuits was quasi-geostrophic and influenced by advection, whereas southern circuits were ageostrophic and dominated by friction. By applying estuarine circulation concepts to tidal and residual dynamics, this work revealed the transition from deep, wide, rotation-influenced northern fjords to narrow, shallow, friction-dominated southern passages. Most of the concepts of estuarine dynamics for plain, shallow estuaries applied to this fjord system.
  • Miniatura
    Ítem
    Water age variability in a Patagonian fjord
    (Journal of Marine Systems, 2020) Pinilla Matamala, Elías; Castillo, Manuel; Pérez-Santos, Iván; Venegas, Oliver; Valle-Levinson, Arnoldo
    Transport time scales are helpful to determine aquatic ecosystem health and sensitivity to pollution. Water age was studied in a Patagonian fjord in Chile with an unstructured three-dimensional hydrodynamic model (MIKE 3) coupled with a high-resolution atmospheric model (WRF). Water age is defined as the time a water parcel has remained since its entrance to a system. Water age is represented in the Puyuhuapi fjord and adjacent Jacaf channel with two tracers: i) freshwater from rivers and ii) ocean water. Hydrodynamic model results showed reasonable stratification structure in the fjord and response to wind forcing. The fjord had high water age values (300–400 days) during autumn-winter due to increased wind stress, which favored vertical mixing and en trainment of subpycnocline waters of higher age. Wind stress decreased during spring-summer, which favored stratification and decreased water age (~100 days). The change of water age at intermediate (50–100 m) and deep (>100 m) layers is asynchronous. Intermediate layers have their lowest annual water age (100 days) during autumn-winter, when deep waters, especially in the northern part of the Puyuhuapi fjord, have the highest annual water age (> 600 days). Increased inflows of dense waters in spring-summer above a sill of the Puyuhuapi fjord (~100 m) renew the deep upstream basins, causing their lowest annual water age values (400 days) at a time when intermediate waters have their highest values.