A gridded data set of upper-ocean hydrographic properties in the Weddell Gyre obtained by objective mapping of Argo float measurements

Abstract

Abstract. The Weddell Gyre plays a crucial role in the modification of climate by advecting heat poleward to the Antarctic ice shelves and by regulating the density of water masses that feed the lowest limb of the global ocean overturning circulation. However, our understanding of Weddell Gyre water mass properties is limited to regions of data availability, primarily along the Prime Meridian. The aim of this paper is to provide a data set of the upper water column properties of the entire Weddell Gyre. Objective mapping was applied to Argo float data in order to produce spatially gridded, time-composite maps of temperature and salinity for fixed pressure levels ranging from 50 to 2000 dbar, as well as temperature, salinity and pressure at the level of the sub-surface temperature maximum. While the data are currently too limited to incorporate time into the gridded structure, the data are extensive enough to produce maps of the entire region across three time-composite periods (2001-2005, 2006-2009 and 2010-2013), which can be used to determine how representative conclusions drawn from data collected along general RV transect lines are on a gyre scale perspective. The work presented here represents the technical prerequisite for addressing climatological research questions in forthcoming studies. The data sets are available in netCDF format at

The Weddell Gyre, Southern Ocean: Present Knowledge and Future Challenges

“…Relatively warm and salty CDW (the voluminous midlayer water of the ACC, with its origins in the North Atlantic; Callahan, ) enters the gyre at its eastern edge and while concurrently rising (Donnelly et al, ) flows toward the southwestern Weddell Sea. This is illustrated in Figure , which shows the temperature of the subsurface temperature maximum from objectively mapped Argo float data (modified from Reeve et al, ). Here it intrudes onto the continental shelves as modified WDW and mixes with cold shelf waters that are made more saline by brine rejection during sea‐ice formation.…”

“…The Weddell Gyre: temperature (°C) at the subsurface temperature maximum, derived from optimally interpolated Argo float data (from Reeve et al, ; http://doi.org/10.17882/42182). The figure shows clearly the penetration of Circumpolar Deep Water (CDW) from the east on the southern side of the gyre, and the rapid cooling of the middepth waters on the western side of the Weddell Sea as Antarctic Bottom Waters are formed.…”

“…This calls for the design of new autonomous technologies, capable of reliably operating in heavy sea‐ice conditions and underneath an ice shelf. A promising step forward is the development and use of under‐ice Argo floats, which track the circulation of water masses in the whole WG, including its largely sea‐ice‐covered southern and western part (Reeve et al, ; Figure ).…”

Decorrelation scales for Arctic Ocean hydrography – Part I: Amerasian Basin

“…One reason is that sea-ice cover greatly inhibits sea surface observation by remote sensing. Another reason is the sparse coverage of in situ ocean measurements due to the inaccessibility and the absence of an Argo float network (that has provided essential data for midlatitude and Southern Ocean studies; e.g., McLean, 2010;Reeve et al, 2016). In the last decade, however, the number of observational activities has been increasing significantly, with the growing concern about the sea-ice retreat and its potential impact on global climate (see, e.g., Ortiz et al, 2011 and references therein).…”

Decorrelation scales for Arctic Ocean Hydrography. Part I: Amerasian Basin

“…One reason is that sea ice cover greatly inhibits sea surface observation by remote sensing. Another reason is the sparse coverage of in-situ ocean measurements due 3 to the inaccessibility and the absence of an Argo float network (that has provided essential data for mid-latitude and Southern Ocean studies [e.g., McLean, 2010;Reeve et al, 2016]). In the last decade, however, the number of observational activities has been increasing significantly, with the growing concern about the sea ice retreat and its potential impact on global climate (see e.g., Ortiz et al [2011] and references therein).…”