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Jin-Yi Yu, Houk Paek, Eric S. Saltzman, and Tong Lee

-mean SLP between 40° and 65°S based on observations from 12 weather stations. Following Yuan and Li (2008) , the PSA* index is defined as the weighted average of Z500 anomalies at three specific locations (referred to as Z1, Z2, and Z3) in the following way: PSA* = (Z1 + Z2 − Z3)/3. Here, Z1 is located at 50°S, 45°W, Z2 is at 45°S, 170°W, and Z3 is at 67.5°S, 120°W. Figure 1f shows the running correlation coefficient between the SAM* and PSA* indices. The correlation was relatively small in the 1960

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Ryan L. Fogt and Alex J. Wovrosh

topography, specifically the nonsymmetric orientation of the continent, such as the high plateau of East Antarctica (which reaches an elevation of over 3000 m) and the western Antarctic Peninsula ( Baines and Fraedrich 1989 ; Lachlan-Cope et al. 2001 ). The ASL has a seasonal movement due to the location of the Rossby long waves in the Southern Hemisphere ( Turner et al. 2013 ), being farther east toward the Antarctic Peninsula in austral summer and farther west toward the Ross Sea in austral winter

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Kate Snow, Andrew McC. Hogg, Bernadette M. Sloyan, and Stephanie M. Downes

Abstract

The influence of freshwater and heat flux changes on Antarctic Bottom Water (AABW) properties are investigated within a realistic bathymetry coupled ocean–ice sector model of the Atlantic Ocean. The model simulations are conducted at eddy-permitting resolution where dense shelf water production dominates over open ocean convection in forming AABW. Freshwater and heat flux perturbations are applied independently and have contradictory surface responses, with increased upper-ocean temperature and reduced ice formation under heating and the opposite under increased freshwater fluxes. AABW transport into the abyssal ocean reduces under both flux changes, with the reduction in transport being proportional to the net buoyancy flux anomaly south of 60°S.

Through inclusion of shelf-sourced AABW, a process absent from most current generation climate models, cooling and freshening of dense source water is facilitated via reduced on-shelf/off-shelf exchange flow. Such cooling is propagated to the abyssal ocean, while compensating warming in the deep ocean under heating introduces a decadal-scale variability of the abyssal water masses. This study emphasizes the fundamental role buoyancy plays in controlling AABW, as well as the importance of the inclusion of shelf-sourced AABW within climate models in order to attain the complete spectrum of possible climate change responses.

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Lee J. Welhouse, Matthew A. Lazzara, Linda M. Keller, Gregory J. Tripoli, and Matthew H. Hitchman

Figs. 1b and 1c . There are subtle differences in location with La Niña events shifted toward the Ross Ice Shelf region stretching into East Antarctica ( Fig. 1c ), while El Niño shows a signal closer to the peninsula ( Fig. 1b ) stretching into the Ross Ice Shelf. We explore these subtle differences on seasonal time scales throughout this work. Recent research indicates the presence of significant nonlinearities, and asymmetries in tropical regions between phases of ENSO ( Frauen et al. 2014

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David P. Schneider, Clara Deser, and Tingting Fan

here (1979–2011), the SPARC stratospheric ozone data are based on regression fits (representing different time scales and processes of variability) to ozonesonde observations. However, these observations are sparse: SPARC included observations from only one location in the SH polar region, Syowa station (69.0°S, 39.6°E). As Syowa is located near the edge of the polar vortex, it does not experience the severe ozone depletion that can occur in the deep interior of the polar vortex ( Eyring et al

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Bradley P. Goodwin, Ellen Mosley-Thompson, Aaron B. Wilson, Stacy E. Porter, and M. Roxana Sierra-Hernandez

anticipated warming of the planet due to increasing greenhouse gas emissions. Fig . 1. Location of the sites in the AP discussed in the paper. However, many factors have been identified as drivers of recent AP/West Antarctic climate change including tropical variability ( Ding et al. 2011 ; Schneider et al. 2012 ; Ding and Steig 2013 ; Clem and Fogt 2015 ), anomalous sea ice concentrations ( Ding and Steig 2013 ), and Amundsen Sea low (ASL) variability ( Fogt et al. 2012 ; Turner et al. 2013

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