NASA supercomputer improves prospects for ocean climate research

Menemenlis, Dimitris; Hill, Christopher N.; Adcrocft, A.; Campin, Jean‐Michel; Cheng, Benny; Ciotti, Bob; Fukumori, Ichiro; Heimbach, Patrick; Henze, Chris; Köhl, Armin; Lee, T.; Stammer, Detlef; Taft, James R.; Zhang, J.

doi:10.1029/2005eo090002

Cited by 131 publications

(111 citation statements)

References 14 publications

Supporting

Mentioning

107

Contrasting

Order By: Relevance

“…Study of the present eddy-free motions on time scales of less than about 2 yr shows a strong coupling in both temperature and velocity between the upper and lower oceans, consistent with a primarily wind-forced response. Ponte (2012), using a different ECCO eddy-permitting state estimate (Menemenlis et al 2005), showed that abyssal noise could seriously compromise the interpretation of sea level variability and hence degrade the heat content estimates at the levels of accuracy needed here.…”

Section: Abyssal Signalsmentioning

confidence: 99%

“…For context, Fig. 9 is taken from the ECCO2, eddy-permitting state estimate of Menemenlis et al (2005), used by Ponte (2012), which shows that the eddy-noise variance (which is likely still underestimated owing to the 18-km horizontal resolution) is about 6 times larger than the background standard deviation. Also shown (Fig.…”

Section: A Variancesmentioning

confidence: 99%

“…The K2011 estimation methodology is similar to ours: a GCM at 18 resolution and 46 vertical layers [version 3 of the Geophysical Fluid Dynamics Laboratory (GFDL)/ NOAA Modular Ocean Model (MOM3); Pacanowski and Griffies 2000] was used in combination with temperature data to estimate abyssal warming. Among the numerous differences, apart from the model itself, are that they combined the Green function technique of Menemenlis et al (2005) with the Lagrange multiplier method: only temperature and salinity data were used, but the denser global observing system observations, including Argo, satellite altimetry, and scatterometry, were omitted; the datasets extended back to 1985; and the computation was run over the 40 yr beginning in 1957. In comparing their results to those of Purkey and Johnson (2010), K2011 used a much finer breakdown into 73 abyssal regions, presumably leaving a larger average residual noise level in each.…”

Section: August 2014 W U N S C H a N D H E I M B A C Hmentioning

confidence: 99%

See 2 more Smart Citations

Bidecadal Thermal Changes in the Abyssal Ocean

Wunsch

Heimbach

2014

Journal of Physical Oceanography

View full text Add to dashboard Cite

A dynamically consistent state estimate is used for the period 1992-2011 to describe the changes in oceanic temperatures and heat content, with an emphasis on determining the noise background in the abyssal (below 2000 m) depths. Interpretation requires close attention to the long memory of the deep ocean, implying that meteorological forcing of decades to thousands of years ago should still be producing trendlike changes in abyssal heat content. Much of the deep-ocean volume remained unobserved. At the present time, warming is seen in the deep western Atlantic and Southern Oceans, roughly consistent with those regions of the ocean expected to display the earliest responses to surface disturbances. Parts of the deeper ocean, below 3600 m, show cooling. Most of the variation in the abyssal Pacific Ocean is comparatively featureless, consistent with the slow, diffusive approach to a steady state expected there. In the global average, changes in heat content below 2000 m are roughly 10% of those inferred for the upper ocean over the 20-yr period. A useful global observing strategy for detecting future change has to be designed to account for the different time and spatial scales manifested in the observed changes. If the precision estimates of heat content change are independent of systematic errors, determining oceanic heat uptake values equivalent to 0.1 W m 22 is possibly attainable over future bidecadal periods.

show abstract

Section: Abyssal Signalsmentioning

confidence: 99%

Section: A Variancesmentioning

confidence: 99%

Section: August 2014 W U N S C H a N D H E I M B A C Hmentioning

confidence: 99%

See 1 more Smart Citation

Bidecadal Thermal Changes in the Abyssal Ocean

Wunsch

Heimbach

2014

Journal of Physical Oceanography

View full text Add to dashboard Cite

show abstract

“…The coupled model is configured on a ''cubed-sphere'' grid encompassing the Arctic domain with open boundaries at around 558N in the Atlantic and Pacific sectors. Prescribed boundary conditions for potential temperature, salinity, flow, and sea surface elevation are provided from previous integrations of a global configuration of the same model [Menemenlis et al, 2005]. The sea ice component follows the viscous-plastic rheology formulation of Hibler [1979] with momentum Journal of Geophysical Research: Oceans…”

Section: A17 Model 18mentioning

confidence: 99%

Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models

Lee

Matrai

Friedrichs

et al. 2016

J. Geophys. Res. Oceans

View full text Add to dashboard Cite

The relative skill of 21 regional and global biogeochemical models was assessed in terms of how well the models reproduced observed net primary productivity (NPP) and environmental variables such as nitrate concentration (NO3), mixed layer depth (MLD), euphotic layer depth (Zeu), and sea ice concentration, by comparing results against a newly updated, quality‐controlled in situ NPP database for the Arctic Ocean (1959–2011). The models broadly captured the spatial features of integrated NPP (iNPP) on a pan‐Arctic scale. Most models underestimated iNPP by varying degrees in spite of overestimating surface NO3, MLD, and Zeu throughout the regions. Among the models, iNPP exhibited little difference over sea ice condition (ice‐free versus ice‐influenced) and bottom depth (shelf versus deep ocean). The models performed relatively well for the most recent decade and toward the end of Arctic summer. In the Barents and Greenland Seas, regional model skill of surface NO3 was best associated with how well MLD was reproduced. Regionally, iNPP was relatively well simulated in the Beaufort Sea and the central Arctic Basin, where in situ NPP is low and nutrients are mostly depleted. Models performed less well at simulating iNPP in the Greenland and Chukchi Seas, despite the higher model skill in MLD and sea ice concentration, respectively. iNPP model skill was constrained by different factors in different Arctic Ocean regions. Our study suggests that better parameterization of biological and ecological microbial rates (phytoplankton growth and zooplankton grazing) are needed for improved Arctic Ocean biogeochemical modeling.

show abstract

“…The MITgcm configuration used covers a limited-area Arctic domain that has open boundaries at ;558 in the Atlantic and Pacific sectors. The exact boundary lines coincide with grid cells in a global cubic sphere MITgcm configuration (Menemenlis et al 2005;Fig. 2).…”

Section: A Model Descriptionmentioning

confidence: 99%

Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing

et al. 2009

View full text Add to dashboard Cite

The authors investigate the response of the Arctic Ocean freshwater budget to changes in the North Atlantic Oscillation (NAO) using a regional-ocean configuration of the Massachusetts Institute of Technology GCM (MITgcm) and carry out several different 10-yr and 30-yr integrations. At 1 / 6 8 (;18 km) resolution the model resolves the major Arctic transport pathways, including Bering Strait and the Canadian Archipelago. Two main calculations are performed by repeating the wind fields of two contrasting NAO years in each run for the extreme negative and positive NAO phases of 1969 and 1989, respectively. These calculations are compared both with a control run and the compiled observationally based freshwater budget estimate of Serreze et al.The results show a clear response in the Arctic freshwater budget to NAO forcing, that is, repeat NAO negative wind forcing results in virtually all freshwater being retained in the Arctic, with the bulk of the freshwater content being pooled in the Beaufort gyre. In contrast, repeat NAO positive forcing accelerates the export of freshwater out of the Arctic to the North Atlantic, primarily via Fram Strait (;900 km 3 yr 21 ) and the Canadian Archipelago (;500 km 3 yr 21 ), with a total loss in freshwater storage of ;13 000 km 3 (15%) after 10 yr. The large increase in freshwater export through the Canadian Archipelago highlights the important role that this gateway plays in redistributing the freshwater of the Arctic to subpolar seas, by providing a direct pathway from the Arctic basin to the Labrador Sea, Gulf Stream system, and Atlantic Ocean.The authors discuss the sensitivity of the Arctic Ocean to long-term fixed extreme NAO states and show that the freshwater content of the Arctic is able to be restored to initial values from a depleted freshwater state after ;20 yr.

show abstract

NASA supercomputer improves prospects for ocean climate research

Cited by 131 publications

References 14 publications

Bidecadal Thermal Changes in the Abyssal Ocean

Bidecadal Thermal Changes in the Abyssal Ocean

Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models

Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing

Contact Info

Product

Resources

About