On the subtropical Northeast Pacific mixed layer depth and its influence on the subduction

2018 ◽  
Vol 37 (3) ◽  
pp. 51-62
Author(s):  
Ruibin Xia ◽  
Chengyan Liu ◽  
Chen Cheng
Keyword(s):  
Mixed Layer ◽  
Mixed Layer Depth ◽  
Layer Depth ◽  
Northeast Pacific

scholarly journals A Diagnostic Model for Mixed Layer Depth Estimation with Application to Ocean Station P in the Northeast Pacific

2009 ◽  
Vol 39 (6) ◽  
pp. 1399-1415 ◽  
Author(s):  
Richard E. Thomson ◽  
Isaac V. Fine
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Mixed Layer ◽  
Mixed Layer Depth ◽  
Depth Estimation ◽  
Surface Fluxes ◽  
Late Winter ◽  
Diagnostic Model ◽  
Layer Depth ◽  
Northeast Pacific

Abstract This paper presents a simple diagnostic model for estimating mixed layer depth based solely on the one-dimensional heat balance equation, the surface heat flux, and the sea surface temperature. The surface fluxes drive heating or cooling of the upper layer whereas the surface temperature acts as a “thermostat” that regulates the vertical extent of the layer. Daily mixed layer depth estimates from the diagnostic model (and two standard bulk mixed layer models) are compared with depths obtained from oceanic profiles collected during the 1956–80 Canadian Weathership program at Station P and more recent (2001–07) profiles from the vicinity of this station from Argo drifters. Summer mixed layer depths from the diagnostic model agree more closely with observed depths and are less sensitive to heat flux errors than those from bulk models. For the Weathership monitoring period, the root-mean-square difference between modeled and observed monthly mean mixed layer depths is ∼6 m for the diagnostic model and ∼10 m for the bulk models. The diagnostic model is simpler to apply than bulk models and sidesteps the need for wind data and turbulence parameterization required by these models. Mixed layer depths obtained from the diagnostic model using NCEP–NCAR reanalysis data reveal that—contrary to reports for late winter—there has been no significant trend in the summer mixed layer depth in the central northeast Pacific over the past 52 yr.

scholarly journals SMAP and CalCOFI Observe Freshening During the 2014-2016 Northeast Pacific Warm Anomaly

2018 ◽  
Author(s):  
Jorge Vazquez ◽  
Jose Gomez-Valdes
Keyword(s):  
Soil Moisture ◽  
Mixed Layer ◽  
Current System ◽  
Mixed Layer Depth ◽  
California Current ◽  
Layer Depth ◽  
Surface Salinity ◽  
California Current System ◽  
Northeast Pacific ◽  
Warm Anomaly

Data from NASA’s Soil Moisture Active Passive Mission (SMAP) and from the California Cooperative Oceanic Fisheries Investigations (CalCOFI) were used to examine the freshening that occurred during 2015-2016 in the Southern California Current System. Overall the freshening was found to be related to the 2014-2016 Northeast Pacific Warm Anomaly. The primary goal was to determine the feasibility of using SMAP data to observe the surface salinity signal associated with the warming. As a first step direct comparisons were done with salinity from the CalCOFI data at one-meter depth. During 2015 SMAP was saltier than CalCOFI by 0.5 PSU, but biases were reduced to < 0.1 PSU during 2016. South of 33°N, and within 100 km of the coast, SMAP was fresher in 2015 by almost 0.2 PSU. CalCOFI showed freshening of 0.1 PSU. North of 33°N SMAP and CalCOFI saw significant freshening in 2016, SMAP by 0.4 PSU and CalCOFI by 0.2 PSU. Differences between SMAP and CalCOFI are consistent with the increased stratification in 2015 and changes in the mixed layer depth.

scholarly journals Decadal variability in the northeast Pacific in a physical-ecosystem model: Role of mixed layer depth and trophic interactions

2008 ◽  
Vol 113 (C2) ◽  
Author(s):  
Michael Alexander ◽  
Antonietta Capotondi ◽  
Arthur Miller ◽  
Fei Chai ◽  
Richard Brodeur ◽  
...  
Keyword(s):  
Mixed Layer ◽  
Trophic Interactions ◽  
Decadal Variability ◽  
Mixed Layer Depth ◽  
Ecosystem Model ◽  
Layer Depth ◽  
Northeast Pacific

Interannual variability of the Tropical Indian Ocean mixed layer depth

2012 ◽  
Vol 40 (3-4) ◽  
pp. 743-759 ◽  
Author(s):  
M. G. Keerthi ◽  
M. Lengaigne ◽  
J. Vialard ◽  
C. de Boyer Montégut ◽  
P. M. Muraleedharan
Keyword(s):  
Indian Ocean ◽  
Interannual Variability ◽  
Mixed Layer ◽  
Mixed Layer Depth ◽  
Tropical Indian Ocean ◽  
Ocean Mixed Layer ◽  
Layer Depth ◽  
Ocean Mixed Layer Depth

scholarly journals Summertime increases in upper-ocean stratification and mixed-layer depth

Nature ◽  
2021 ◽  
Vol 591 (7851) ◽  
pp. 592-598
Author(s):  
Jean-Baptiste Sallée ◽  
Violaine Pellichero ◽  
Camille Akhoudas ◽  
Etienne Pauthenet ◽  
Lucie Vignes ◽  
...  
Keyword(s):  
Mixed Layer ◽  
Mixed Layer Depth ◽  
Upper Ocean ◽  
Layer Depth ◽  
Ocean Stratification

A numerical study on the role of atmospheric forcing on mixed layer depth variability in the Bay of Bengal using a regional ocean model

2021 ◽  
Author(s):  
Sumit Dandapat ◽  
Arun Chakraborty ◽  
Jayanarayanan Kuttippurath ◽  
Chirantan Bhagawati ◽  
Radharani Sen
Keyword(s):  
Mixed Layer ◽  
Bay Of Bengal ◽  
Numerical Study ◽  
Mixed Layer Depth ◽  
Ocean Model ◽  
Atmospheric Forcing ◽  
Layer Depth ◽  
Regional Ocean Model

scholarly journals Global sensitivity analysis of the Indian monsoon during the Pleistocene

2015 ◽  
Vol 11 (1) ◽  
pp. 45-61 ◽  
Author(s):  
P. A. Araya-Melo ◽  
M. Crucifix ◽  
N. Bounceur
Keyword(s):  
Sensitivity Analysis ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Mixed Layer ◽  
Global Sensitivity Analysis ◽  
Indian Monsoon ◽  
Mixed Layer Depth ◽  
Sea Surface ◽  
Layer Depth ◽  
Global Sensitivity

Abstract. The sensitivity of the Indian monsoon to the full spectrum of climatic conditions experienced during the Pleistocene is estimated using the climate model HadCM3. The methodology follows a global sensitivity analysis based on the emulator approach of Oakley and O'Hagan (2004) implemented following a three-step strategy: (1) development of an experiment plan, designed to efficiently sample a five-dimensional input space spanning Pleistocene astronomical configurations (three parameters), CO2 concentration and a Northern Hemisphere glaciation index; (2) development, calibration and validation of an emulator of HadCM3 in order to estimate the response of the Indian monsoon over the full input space spanned by the experiment design; and (3) estimation and interpreting of sensitivity diagnostics, including sensitivity measures, in order to synthesise the relative importance of input factors on monsoon dynamics, estimate the phase of the monsoon intensity response with respect to that of insolation, and detect potential non-linear phenomena. By focusing on surface temperature, precipitation, mixed-layer depth and sea-surface temperature over the monsoon region during the summer season (June-July-August-September), we show that precession controls the response of four variables: continental temperature in phase with June to July insolation, high glaciation favouring a late-phase response, sea-surface temperature in phase with May insolation, continental precipitation in phase with July insolation, and mixed-layer depth in antiphase with the latter. CO2 variations control temperature variance with an amplitude similar to that of precession. The effect of glaciation is dominated by the albedo forcing, and its effect on precipitation competes with that of precession. Obliquity is a secondary effect, negligible on most variables except sea-surface temperature. It is also shown that orography forcing reduces the glacial cooling, and even has a positive effect on precipitation. As regards the general methodology, it is shown that the emulator provides a powerful approach, not only to express model sensitivity but also to estimate internal variability and detect anomalous simulations.

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