Data-Based Meridional Overturning Streamfunctions for the Global Ocean

Talley, Lynne D.; Reid, Joseph L.; Robbins, Paul E.

doi:10.1175/1520-0442(2003)016<3213:dmosft>2.0.co;2

Cited by 338 publications

(310 citation statements)

References 71 publications

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“…Among the 'good' models, the present day maximum strength of the AMOC varies from 15.8 to 18.8 Sv, which is within to the range of observational estimates of 18 ± 3-5 Sv (Talley et al 2003).…”

Section: The Glacial Ocean Circulation Of the Selected Runssupporting

confidence: 71%

Optimal tuning of a GCM using modern and glacial constraints

et al. 2010

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In climate models, many parameters used to resolve subgrid scale processes can be adjusted through a tuning exercise to fit the model's output to target climatologies. We present an objective tuning of a low resolution Atmosphere-Ocean General Circulation Model (GCM) called FAMOUS where ten model parameters are varied together using a Latin hypercube sampling method to create an ensemble of 100 models. The target of the tuning consists of a wide range of modern climate diagnostics and also includes glacial tropical sea surface temperature. The ensemble of models created is compared to the target using an Arcsin Mielke score. We investigate how the tuning method used and the addition of glacial constraints impact on the present day and glacial climates of the chosen models. Rather than selecting a single configuration which optimises the metric in all the diagnostics, we obtain a subset of nine 'good' models which display great differences in their climate but which, in some sense, are all better than the original configuration. In those simulations, the global temperature response to last glacial maximum forcings is enhanced compared to the control simulation and the glacial Atlantic Ocean circulation is more in agreement with observations. Our study demonstrates that selecting a single 'optimal' configuration, relying only on present day constraints may lead to misrepresenting climates different to that of today.

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Section: The Glacial Ocean Circulation Of the Selected Runssupporting

confidence: 71%

Optimal tuning of a GCM using modern and glacial constraints

et al. 2010

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“…The northward transport of AABW is underestimated in IPSLCM5 and CNRMCM5 relative to observational estimates (e.g., Talley et al 2003). All models underestimate the observed strength of the ACC (e.g., Talley et al 2003;Cunningham 2003), although simulated transport in IPSLCM5 and CNRMCM5 is more similar to the observed transport relative to the much lower transport of IPSLCM4 (i.e., 60-70 Sv lower).…”

Section: Ocean-atmosphere Interactions and Ocean Surface Propertiesmentioning

confidence: 74%

“…In the Equatorial Pacific, MLD min is overestimated in all models, particularly CNRMCM5. Table 2 shows that the magnitude of simulated NADW transport is low relative to observations in IPSLCM4, while those of IPSLCM5 and CNRMCM5 are within the low end of the observational uncertainty (e.g., Talley et al 2003;Ganachaud 2003). The northward transport of AABW is underestimated in IPSLCM5 and CNRMCM5 relative to observational estimates (e.g., Talley et al 2003).…”

Section: Ocean-atmosphere Interactions and Ocean Surface Propertiesmentioning

confidence: 89%

“…Table 2 shows that the magnitude of simulated NADW transport is low relative to observations in IPSLCM4, while those of IPSLCM5 and CNRMCM5 are within the low end of the observational uncertainty (e.g., Talley et al 2003;Ganachaud 2003). The northward transport of AABW is underestimated in IPSLCM5 and CNRMCM5 relative to observational estimates (e.g., Talley et al 2003). All models underestimate the observed strength of the ACC (e.g., Talley et al 2003;Cunningham 2003), although simulated transport in IPSLCM5 and CNRMCM5 is more similar to the observed transport relative to the much lower transport of IPSLCM4 (i.e., 60-70 Sv lower).…”

Section: Ocean-atmosphere Interactions and Ocean Surface Propertiesmentioning

confidence: 89%

“…For assessing modeled ocean-atmosphere net heat fluxes (i.e., sum of solar radiation, longwave radiation, sensible heat transfer by conduction and convection, and latent heat transfer by evaporation of sea surface water), we use the 1981-2005 reanalysis of Yu et al (2007), which provides a monthly climatology combining observations from surface meteorological stations and satellite data. Finally, for data-based estimates of watermass transport of North Atlantic Deep Water, Antarctic Bottom Water, and the Antarctic Circumpolar Current, we relied on estimations from Talley et al (2003), Ganachaud (2003), Cunningham (2003).…”

Section: Assessment Methodsmentioning

confidence: 99%

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Skill assessment of three earth system models with common marine biogeochemistry

et al. 2012

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We have assessed the ability of a common ocean biogeochemical model, PISCES, to match relevant modern data fields across a range of ocean circulation fields from three distinct Earth system models: IPSL-CM4-LOOP, IPSL-CM5A-LR and CNRM-CM5.1. The first of these Earth system models has contributed to the IPCC 4th assessment report, while the latter two are contributing to the ongoing IPCC 5th assessment report. These models differ with respect to their atmospheric component, ocean subgrid-scale physics and resolution. The simulated vertical distribution of biogeochemical tracers suffer from biases in ocean circulation and a poor representation of the sinking fluxes of matter. Nevertheless, differences between upper and deep ocean model skills significantly point to changes in the underlying model representations of ocean circulation. IPSL-CM5A-LR and CNRM-CM5.1 poorly represent deep-ocean circulation compared to IPSL-CM4-LOOP degrading the vertical distribution of biogeochemical tracers. However, their representations of surface wind, wind stress, mixed-layer depth and geostrophic circulations (e.g., Antarctic Circumpolar Current) have been improved compared to IPSL-CM4-LOOP. These improvements result in a better representation of large-scale structure of biogeochemical fields in the upper ocean. In particular, a deepening of 20-40 m of the summer mixed-layer depth allows to capture the 0-0.5 lgChl L -1 concentrations class of surface chlorophyll in the Southern Ocean. Further improvements in the representation of the ocean mixedlayer and deep-ocean ventilation are needed for the next generations of models development to better simulate marine biogeochemistry. In order to better constrain ocean dynamics, we suggest that biogeochemical or passive tracer modules should be used routinely for both model development and model intercomparisons.

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Intermediate and deep water formation in the Okinawa Trough

et al. 2013

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Water mass formation in the intermediate and deep layers of the Okinawa Trough is investigated using two distinct data sets: a quasi‐climatological data set of the water properties of the minimum salinity surface produced from Argo float profiles and historical CTD data, and a velocity data set in the Kerama Gap measured by moored current meters during June 2009 to June 2011. The formation process of Okinawa Trough Intermediate Water is explained on the basis of horizontal advection and mixing of North Pacific Intermediate Water (NPIW) and South China Sea Intermediate Water (SCSIW). The salinity‐minimum water intruding into the Okinawa Trough through the channel east of Taiwan is approximately composed of 45% NPIW and 55% SCSIW, while that through the Kerama Gap is 75% NPIW and 25% SCSIW. Salinities of these water masses increase in the Okinawa Trough due to strong diapycnal diffusion; its coefficient is estimated as 6.8–21.5 × 10−4 m2 s−1 based on a simple advection‐diffusion equation. On the other hand, deep water in the Okinawa Trough, below the sill depth of the Kerama Gap (∼1100 m), is ventilated by overflow in the bottom layer of the Kerama Gap down to the deepest layer (∼2000 m) in the southern Okinawa Trough. A simple box model predicts that this bottom overflow (0.18–0.35 Sv) causes strong upwelling (3.8–7.6 × 10−6 m s−1) in the southern Okinawa Trough, which must be maintained by buoyancy gain of the deep water due to strong diapycnal diffusion (4.8–9.5 × 10−4 m2 s−1).

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Data-Based Meridional Overturning Streamfunctions for the Global Ocean

Cited by 338 publications

References 71 publications

Optimal tuning of a GCM using modern and glacial constraints

Optimal tuning of a GCM using modern and glacial constraints

Skill assessment of three earth system models with common marine biogeochemistry

Intermediate and deep water formation in the Okinawa Trough

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