Middepth decadal warming and freshening in the South Atlantic

Details

• Journal Title:
  Journal of Geophysical Research: Oceans
• Personal Author:
  Giglio, Donata ; Johnson, Gregory C.
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research) ; PMEL (Pacific Marine Environmental Laboratory) ; JISAO (Joint Institute for the Study of the Atmosphere and Ocean)
• Description:
  South Atlantic Ocean middepth water property (temperature, salinity, oxygen, nutrients, etc.) distributions are set by salty, well-ventilated, and relatively nutrient-poor North Atlantic Deep Water (NADW) spreading southward toward the Southern Ocean underneath fresher, well-ventilated, and relatively nutrient-poor northward spreading Antarctic Intermediate Water (AAIW). The layer between the NADW and AAIW is oxygen-poor and nutrient-rich, with small vertical temperature gradients. Salinity stratification dominates the vertical density gradient, hence the layer is referred to as Salinity Stratified Layer (SSL). Decadal warming (0.044 degrees C decade(-1)) and freshening (0.006 g kg(-1) decade(-1)) of this layer are analyzed using Argo data, a climatology, and repeat hydrographic sections. Warming within the SSL accumulates heat at a rate of similar to 20 TW, is unlikely to be caused by vertical heave, and is consistent with anomalous southward advection of order 10(2) km decade(-1) in the Atlantic Meridional Overturning Circulation. Salinity changes within the SSL are consistent with a downward velocity anomaly of order 10 m decade(-1).
• Source:
  Journal of Geophysical Research-Oceans, 122(2), 973-979.
• DOI:
  https://doi.org/10.1002/2016JC012246
• Document Type:
  Journal Article
• Funding:
  Grant no. NA15OAR4320063
• Rights Information:
  Other
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha256:f78f5afbcc71b11c84f51d58c0260795bb0af3b9fad32980f01f61859488a154
• Download URL:
  https://repository.library.noaa.gov/view/noaa/17295/noaa_17295_DS1.pdf
• File Type:
  [PDF - 5.05 MB ]