Gridded Freshwater Content Data

Estimates of liquid freshwater content (FWC) of the Beaufort Gyre region (BGR) are computed following Proshutinsky et al. (2009) using CTD, XCTD, and UCTD profiles collected each year from July through October. The FWC is calculated using optimal interpolation on a 50-km square grid between 70˚N and 80˚N, and 130˚W - 170˚W, and where water depths exceed 300 m. Spatially-integrated fresh water volumes for the BGR (encompassing an area of 1.023 x 10⁶ km²) are labelled for each year on each panel in Figure 2 (and shown in Figure 1), with uncertainties determined from combining the uncertainties in the profiles with the optimal interpolation errors shown in Figure 3.

The most up-to-date FWC data (2003-2023) can be found here. This dataset includes the FWC in each grid cell and its error as well as the total FWC and its error.

Figure 1: Total FWC in the BGR based on hydrographic measurements from July to October each year.

Figure 2: FWC in the BGR based on hydrographic measurements each year. The black dots indicate the locations of observational sites. Numbers at the bottom of each panel indicate total FWC in the region (10³ km³) and root‐mean‐square error of the freshwater content interpolation (10³ km³). The 300m and 3000m isobaths are shown in grey.

Figure 3: FWC errors in the Beaufort Gyre region associated with the optimal interpolation method. The black dots indicate the locations of observational sites. Numbers at the bottom of each panel indicate the root‐mean‐square error of the freshwater content interpolation (10³ km³). The 300m and 3000m isobaths are shown in grey.

References

Proshutinsky, A., R. Krishfield, M.-L. Timmermans, J. Toole, E. Carmack, F. Mclaughlin, W. J. Williams, S. Zimmermann, M. Itoh, & K. Shimada (2009), Beaufort Gyre freshwater reservoir: State and variability from observations, Journal of Geophysical Research, 114, 1–25, doi:10.1029/2008JC005104.