Sea Surface Salinity (SSS) indicates the amount of salt dissolved in seawater. Average seawater salinity is around 35 ppt (parts per thousand) or 3.5%. While there is generally small variation in sea surface salinity, it is an important indicator and driver of oceanic circulation. Salinity is decreased in areas of freshwater input either through rain, river runoff, or ice melt, and is increased through evaporation. Salinity, along with temperature, are important factors that determine the density of seawater. Tracking changes in sea surface salinity provides insight to ocean and climate studies. This layer uses The New Zealand Earth System Model (NZESM) with data from 2002-2019. This recently developed model incorporates component models of ocean biogeochemistry and other aspects of biology and chemistry that provide a highly complex model of the climate system (Behrens et al. 2020, Williams et al. 2016). The NZESM model differs from the UK Earth System Model (UKESM) in that it includes a high-resolution regional ocean model for the seas around New Zealand, and it includes a representation of the variability of solar radiation in atmospheric chemistry, as solar input is an important driver of climate variability at southern high latitudes. In the NZESM the nested high-resolution ocean model domain spans from 132.7°E to 143.7°W and 60.17°S to 10.75°S with a nominal resolution of 1/5°, which translates into grid sizes of 12 to 20 km. The horizontal grid has 75 vertical levels with a thickness of 1 m at surface and increasing with depth to about 250 m. Environmental parameters were obtained from the NZESM for the midpoint of every 1x1 km cell within the New Zealand region. The interpolation of all 2-D fields for each grid point of the 1 km target grid was done through bilinear interpolation of all surrounding model grid cells, after extrapolating ocean values onto land. For the interpolation of 3-D seafloor variables, a similar approach was applied, but with consideration of vertical model grid and model bathymetry.

Reference:

Behrens, E., J. Williams, O. Morgenstern, P. Sutton, G. Rickard, and M. J. M. Williams. 2020. Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super-Gyre Circulation Implications. Journal of Advances in Modeling Earth Systems 12:e2019MS001996. https://doi.org/10.1029/2019MS001996

Williams, J., Morgenstern, O., Varma, V., Behrens, E., Hayek, W., Oliver, H., Dean, S., Mullan, B., Frame, D. (2016) Development of the New Zealand Earth System Model: NZESM. Weather and Climate, 36: 25-44. https://doi.org/10.2307/26779386

Sea Surface Salinity (SSS) indicates the amount of salt dissolved in seawater. Average seawater salinity is around 35 ppt (parts per thousand) or 3.5%. While there is generally small variation in sea surface salinity, it is an important indicator and driver of oceanic circulation. Salinity is decreased in areas of freshwater input either through rain, river runoff, or ice melt, and is increased through evaporation. Salinity, along with temperature, are important factors that determine the density of seawater. Tracking changes in sea surface salinity provides insight to ocean and climate studies. This layer uses The New Zealand Earth System Model (NZESM) with data from 2002-2019. This recently developed model incorporates component models of ocean biogeochemistry and other aspects of biology and chemistry that provide a highly complex model of the climate system (Behrens et al. 2020, Williams et al. 2016). The NZESM model differs from the UK Earth System Model (UKESM) in that it includes a high-resolution regional ocean model for the seas around New Zealand, and it includes a representation of the variability of solar radiation in atmospheric chemistry, as solar input is an important driver of climate variability at southern high latitudes. In the NZESM the nested high-resolution ocean model domain spans from 132.7°E to 143.7°W and 60.17°S to 10.75°S with a nominal resolution of 1/5°, which translates into grid sizes of 12 to 20 km. The horizontal grid has 75 vertical levels with a thickness of 1 m at surface and increasing with depth to about 250 m. Environmental parameters were obtained from the NZESM for the midpoint of every 1x1 km cell within the New Zealand region. The interpolation of all 2-D fields for each grid point of the 1 km target grid was done through bilinear interpolation of all surrounding model grid cells, after extrapolating ocean values onto land. For the interpolation of 3-D seafloor variables, a similar approach was applied, but with consideration of vertical model grid and model bathymetry.

Reference:

Behrens, E., J. Williams, O. Morgenstern, P. Sutton, G. Rickard, and M. J. M. Williams. 2020. Local Grid Refinement in New Zealand's Earth System Model: Tasman Sea Ocean Circulation Improvements and Super-Gyre Circulation Implications. Journal of Advances in Modeling Earth Systems 12:e2019MS001996. https://doi.org/10.1029/2019MS001996

Williams, J., Morgenstern, O., Varma, V., Behrens, E., Hayek, W., Oliver, H., Dean, S., Mullan, B., Frame, D. (2016) Development of the New Zealand Earth System Model: NZESM. Weather and Climate, 36: 25-44. https://doi.org/10.2307/26779386