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Ice front blocking of ocean heat transport to an Antarctic ice shelf 期刊论文
NATURE, 2020, 578 (7796) : 568-+
作者:  Alexandrov, Ludmil B.;  Kim, Jaegil;  Haradhvala, Nicholas J.;  Huang, Mi Ni;  Ng, Alvin Wei Tian;  Wu, Yang;  Boot, Arnoud;  Covington, Kyle R.;  Gordenin, Dmitry A.;  Bergstrom, Erik N.;  Islam, S. M. Ashiqul;  Lopez-Bigas, Nuria;  Klimczak, Leszek J.;  McPherson, John R.;  Morganella, Sandro;  Sabarinathan, Radhakrishnan;  Wheeler, David A.;  Mustonen, Ville;  Getz, Gad;  Rozen, Steven G.;  Stratton, Michael R.
收藏  |  浏览/下载:46/0  |  提交时间:2020/05/13

The front of the Getz Ice Shelf in West Antarctica creates an abrupt topographic step that deflects ocean currents, suppressing 70% of the heat delivery to the ice sheet.


Mass loss from the Antarctic Ice Sheet to the ocean has increased in recent decades, largely because the thinning of its floating ice shelves has allowed the outflow of grounded ice to accelerate(1,2). Enhanced basal melting of the ice shelves is thought to be the ultimate driver of change(2,3), motivating a recent focus on the processes that control ocean heat transport onto and across the seabed of the Antarctic continental shelf towards the ice(4-6). However, the shoreward heat flux typically far exceeds that required to match observed melt rates(2,7,8), suggesting that other critical controls exist. Here we show that the depth-independent (barotropic) component of the heat flow towards an ice shelf is blocked by the marked step shape of the ice front, and that only the depth-varying (baroclinic) component, which is typically much smaller, can enter the sub-ice cavity. Our results arise from direct observations of the Getz Ice Shelf system and laboratory experiments on a rotating platform. A similar blocking of the barotropic component may occur in other areas with comparable ice-bathymetry configurations, which may explain why changes in the density structure of the water column have been found to be a better indicator of basal melt rate variability than the heat transported onto the continental shelf(9). Representing the step topography of the ice front accurately in models is thus important for simulating ocean heat fluxes and induced melt rates.


  
The Entrainment Rate of Non-Boussinesq Hazardous Geophysical Gas-Particle Flows: An Experimental Model With Application to Pyroclastic Density Currents 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2019, 46 (22) : 12851-12861
作者:  Dellino, P.;  Dioguardi, F.;  Doronzo, D. M.;  Mele, D.
收藏  |  浏览/下载:14/0  |  提交时间:2020/02/17
Pyroclastic density currents  Snow avalanches  Entrainment rate  
Magnetic Effects of Plasma Pressure Gradients in the Upper F Region 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2019, 46 (5) : 2355-2363
作者:  Laundal, K. M.;  Hatch, S. M.;  Moretto, T.
收藏  |  浏览/下载:25/0  |  提交时间:2019/11/26
polar ionosphere  plasma density  magnetic field fluctuations  Swarm  diamagnetic currents  polar cap patch  
The Potential Role of Atmospheric Bores and Gravity Waves in the Initiation and Maintenance of Nocturnal Convection over the Southern Great Plains 期刊论文
JOURNAL OF THE ATMOSPHERIC SCIENCES, 2019, 76 (1) : 43-68
作者:  Parsons, David B.;  Haghi, Kevin R.;  Halbert, Kelton T.;  Elmer, Blake;  Wang, Junhong
收藏  |  浏览/下载:21/0  |  提交时间:2019/04/09
North America  Convection  Gravity waves  Mesoscale processes  Density currents  Diurnal effects