Amundsen and <scp>B</scp>ellingshausen <scp>S</scp>eas simulation with optimized ocean, sea ice, and thermodynamic ice shelf model parameters

Nakayama, Yoshihiro; Menemenlis, Dimitris; Schodlok, Michael; Rignot, Eric

doi:10.1002/2016jc012538

Cited by 43 publications

(104 citation statements)

References 65 publications

(181 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, our data also show nonnegligible quantities of GMW at the continental shelf edge with column inventories up to 1 m and mean values of 0.68 m. The central channel has mean column inventories of 0.77 m, similar to recent modeling studies (Nakayama et al, 2014). However, the eastern channel shows higher concentrations than models predict (up to 0.85 m; Nakayama et al, 2014), although a 10-year model run recently showed an accumulated 4 m of GMW here (Nakayama et al, 2017).…”

Section: Gmw Signature From Noble Gasessupporting

confidence: 84%

“…The model results presented by Nakayama et al. (, ) predicted that the central channel should contain higher GMW content than the eastern channel, yet our data show greater values in the eastern channel, with the GMW content in the central channel associated with a recirculation and GMW flowing on‐shelf. This emphasizes our need to improve the understanding of the transport across these channels at the continental shelf edge and how and where GMW flows off the continental shelf.…”

Section: Discussioncontrasting

confidence: 59%

See 1 more Smart Citation

Upper Ocean Distribution of Glacial Meltwater in the Amundsen Sea, Antarctica

2019

View full text Add to dashboard Cite

Pine Island Ice Shelf, in the Amundsen Sea, is losing mass due to increased heat transport by warm ocean water penetrating beneath the ice shelf and causing basal melt. Tracing this warm deep water and the resulting glacial meltwater can identify changes in melt rate and the regions most affected by the increased input of this freshwater. Here, optimum multiparameter analysis is used to deduce glacial meltwater fractions from independent water mass characteristics (standard hydrographic observations, noble gases, and oxygen isotopes), collected during a ship‐based campaign in the eastern Amundsen Sea in February–March 2014. Noble gases (neon, argon, krypton, and xenon) and oxygen isotopes are used to trace the glacial melt and meteoric water found in seawater, and we demonstrate how their signatures can be used to rectify the hydrographic trace of glacial meltwater, which provides a much higher‐resolution picture. The presence of glacial meltwater is shown to mask the Winter Water properties, resulting in differences between the water mass analyses of up to 4‐g/kg glacial meltwater content. This discrepancy can be accounted for by redefining the “pure” Winter Water endpoint in the hydrographic glacial meltwater calculation. The corrected glacial meltwater content values show a persistent signature between 150 and 400 m of the water column across all of the sample locations (up to 535 km from Pine Island Ice Shelf), with increased concentration toward the west along the coastline. It also shows, for the first time, the signature of glacial meltwater flowing off‐shelf in the eastern channel.

show abstract

Section: Gmw Signature From Noble Gasessupporting

confidence: 84%

Section: Discussioncontrasting

confidence: 59%

Upper Ocean Distribution of Glacial Meltwater in the Amundsen Sea, Antarctica

2019

View full text Add to dashboard Cite

show abstract

“…Meanwhile, there has been a great deal of effort in the modeling of ice-ocean interactions in the Amundsen (e.g., Dutrieux et al, 2014;Kimura et al, 2017;Nakayama et al, 2017;Payne et al, 2007;Robertson, 2013;St-Laurent et al, 2015). While regional ocean models have been successful in reproducing ocean circulation 10.1029/2018GL080383 and its link to bulk ice-shelf melt, ice modeling suggest that the location of ice removal from an ice shelf, in addition to its bulk value, may impact its buttressing capacity (Arthern & Williams, 2017;Goldberg & Heimbach, 2013;Goldberg et al, 2012;Seroussi et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, there has been a great deal of effort in the modeling of ice-ocean interactions in the Amundsen (e.g., Dutrieux et al, 2014;Kimura et al, 2017;Nakayama et al, 2017;Payne et al, 2007;Robertson, 2013;St-Laurent et al, 2015). While regional ocean models have been successful in reproducing ocean circulation RESEARCH LETTER 10.1029/2018GL080383 Key Points: • Satellite measurement of melt rates shows high spatial variability under two fast-flowing ice shelves • Ice-sheet response to ice shelf melt depends on the pattern of melt rates as well as their spatial average • The ability of an ocean model to reproduce this pattern depends on accurate bathymetry and ice shelf draft data…”

Section: Introductionmentioning

confidence: 99%

How Accurately Should We Model Ice Shelf Melt Rates?

Goldberg

Gourmelen

Kimura

et al. 2019

Geophysical Research Letters

127

View full text Add to dashboard Cite

Assessment of ocean‐forced ice sheet loss requires that ocean models be able to represent sub‐ice shelf melt rates. However, spatial accuracy of modeled melt is not well investigated, and neither is the level of accuracy required to assess ice sheet loss. Focusing on a fast‐thinning region of West Antarctica, we calculate spatially resolved ice‐shelf melt from satellite altimetry and compare against results from an ocean model with varying representations of cavity geometry and ocean physics. Then, we use an ice‐flow model to assess the impact of the results on grounded ice. We find that a number of factors influence model‐data agreement of melt rates, with bathymetry being the leading factor; but this agreement is only important in isolated regions under the ice shelves, such as shear margins and grounding lines. To improve ice sheet forecasts, both modeling and observations of ice‐ocean interactions must be improved in these critical regions.

show abstract

“…Schodlok et al () modeled southward heat transport and CDW thickness peaking in fall (March–May) in the eastern trough, and St‐Laurent et al () modeled a late winter (August–October) minimum in heat content below 250 m at PIG. Nakayama et al () find no large seasonal variability at 552 m at the eastern trough shelf break, though they find January warmer and saltier than June at 222 m. Year‐round hydrographic observations are therefore needed to resolve this debate.…”

Section: Introductionmentioning

confidence: 99%

Variation in the Distribution and Properties of Circumpolar Deep Water in the Eastern Amundsen Sea, on Seasonal Timescales, Using Seal‐Borne Tags

Mallett

Boehme

Fedak

et al. 2018

Geophysical Research Letters

View full text Add to dashboard Cite

In the Amundsen Sea, warm saline Circumpolar Deep Water (CDW) crosses the continental shelf toward the vulnerable West Antarctic ice shelves, contributing to their basal melting. Due to lack of observations, little is known about the spatial and temporal variability of CDW, particularly seasonally. A new data set of 6,704 seal tag temperature and salinity profiles in the easternmost trough between February and December 2014 reveals a CDW layer on average 49 dbar thicker in late winter (August to October) than in late summer (February to April), the reverse seasonality of that seen at moorings in the western trough. This layer contains more heat in winter, but on the 27.76 kg/m 3 density surface CDW is 0.32 ∘ C warmer in summer than in winter, across the northeastern Amundsen Sea, which may indicate that wintertime shoaling offshelf changes CDW properties onshelf. In Pine Island Bay these seasonal changes on density surfaces are reduced, likely by gyre circulation. Plain Language SummaryIn the Amundsen Sea, Antarctica, warm salty water crosses the continental shelf from the deep open ocean, toward the vulnerable West Antarctic ice shelves, bringing heat to help melt them from underneath. Due to lack of observations, little is known about how this flow of warm water varies in space and time, particularly seasonally. Between February and December 2014, in a trough in the eastern Amundsen Sea, 6,704 profiles were collected by sensors attached to seals, measuring temperature and salinity as the seals return from dives up to 1,200 m deep. These data showed that this warm (∼1 ∘ C) deep layer is on average ∼50 m thicker in late winter (August to October) than in late summer (February to April), the reverse seasonality of that seen within a trough in the western Amundsen Sea. This warm layer contains more heat in winter but on a surface of constant density is 0.32 ∘ C warmer in summer than in winter, across the northeastern Amundsen Sea. This may indicate that in winter the deep waters offshelf rise, allowing different water onto the continental shelf. In Pine Island Bay these seasonal changes on density surfaces are reduced, probably because here the water circulates and mixes.

show abstract

Amundsen and Bellingshausen Seas simulation with optimized ocean, sea ice, and thermodynamic ice shelf model parameters

Cited by 43 publications

References 65 publications

Upper Ocean Distribution of Glacial Meltwater in the Amundsen Sea, Antarctica

Upper Ocean Distribution of Glacial Meltwater in the Amundsen Sea, Antarctica

How Accurately Should We Model Ice Shelf Melt Rates?

Variation in the Distribution and Properties of Circumpolar Deep Water in the Eastern Amundsen Sea, on Seasonal Timescales, Using Seal‐Borne Tags

Contact Info

Product

Resources

About