Research ArticleOCEANOGRAPHY

Rapid Red Sea Deep Water renewals caused by volcanic eruptions and the North Atlantic Oscillation

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Science Advances  27 Jun 2018:
Vol. 4, no. 6, eaar5637
DOI: 10.1126/sciadv.aar5637
  • Fig. 1 Sections of potential temperature (°C) along the central axis in the Red Sea collected in 1982, 1983, 1987, 1995, 2001, and 2011.

    The dotted vertical lines mark the locations of the CTD profiles, and regions without observations are left blank. The color map in the range of 21.1° to 22°C is chosen to highlight the changes and structures of the deep water.

  • Fig. 2 Comparisons of the seasonal and interannual variability between the modeled and observed sea surface temperatures.

    (A) Monthly means and (B) monthly anomalies for the basin averaged sea surface temperatures derived from the MITgcm simulation and OISST. The monthly anomalies are relative to the 1982–2001 monthly climatological means, and 5-month moving averaging is applied. The dashed lines indicate the 1982 El Chichón and 1991 Mount Pinatubo eruptions.

  • Fig. 3 Deep water formation events during the period 1982–2001.

    (A) Time series of modeled vertical temperature profiles in the northern Red Sea (34.6°E, 27.2°N; see fig. S1 for the locations). (B) Changes in the volumes of the new deep water with potential temperatures lower than 21.4°C. (C) Annual contributions from the open-ocean deep convection and combined outflows from the Gulfs of Suez and Aqaba to the deep water formation. (D) Winter (January through March) surface air temperature anomalies normalized by the 1951–1980 SD in the northern Red Sea (see fig. S1 for the location) and the corresponding winter (January through March) NAO indices.

  • Fig. 4 Modeled sea surface temperatures and deep convection regions during the peak stages in the deep water formation years.

    The dates refer to the middle day of the 3-day averaged model outputs. The deep convection regions are diagnosed as the area where the density difference between the surface and the bottom is less than 0.1 kg/m3 and are separated from the nondeep-convection regions by the black lines. The 21.4°C isotherms are marked by the white lines. The deep convection regions are generally collocated with cold waters and tend to be at the western side of the basin.

  • Fig. 5 Contributions from the outflows to the RSDW in the 1983 winter as illustrated by the potential temperature, salinity, and tracer sections located at the downstream of the outflows.

    The dates are referring to the middle day of the 3-day averaged model outputs. See fig. S1 for the location of the section in the Red Sea. The overflows from the Gulfs of Suez and Aqaba are tagged with tracers. The 21.4°C contours of the potential temperature are also plotted as white lines in each section when present.

  • Fig. 6 Surface heat flux anomalies for the deep water formation events.

    (A) Composite maps of winter (January through March) anomalies of the surface wind (vectors), temperature (shadings), and sea-level pressure (contours) during the deep water formation years (1983, 1989, 1992, and 1993) derived from the ERA-Interim reanalysis data. The anomalies are relative to the 1982–2001 monthly climatological mean. (B) Monthly anomalies for the basin-averaged radiative, latent, and sensible heat fluxes from the model results. Positive value indicates heat gain by the Red Sea. The radiative flux is the net downward flux of the short- and long-wave radiative fluxes. The monthly anomalies are relative to the 1982–2001 monthly climatological means, and 5-month moving averaging is applied. The vertical dashed lines indicate the 1982 El Chichón and 1991 Mount Pinatubo eruptions.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/6/eaar5637/DC1

    fig. S1. The bathymetry of the Red Sea.

    fig. S2. Sections of salinity along the central axis in the Red Sea collected in 1982, 1983, 1987, 1995, 2001, and 2011.

    fig. S3. Time series of modeled vertical salinity profiles in the northern Red Sea.

    fig. S4. Axial potential temperature sections plotted from the model results for comparing with the corresponding observed sections in Fig. 1.

    fig. S5. Schematic of deep water formation in the northern Red Sea from three different sources.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. The bathymetry of the Red Sea.
    • fig. S2. Sections of salinity along the central axis in the Red Sea collected in 1982, 1983, 1987, 1995, 2001, and 2011.
    • fig. S3. Time series of modeled vertical salinity profiles in the northern Red Sea.
    • fig. S4. Axial potential temperature sections plotted from the model results for comparing with the corresponding observed sections in Fig. 1.
    • fig. S5. Schematic of deep water formation sin the northern Red Sea from three different sources.

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