| Satellite altimetry is a powerful tool for estimating global sea level change, monitoring ocean circulation, determining global ocean surface topography in the open oceans. However, for the near shore regions, satellite altimetry suffers from drawbacks and its accuracy can hardly be improved. In order to fill in this missing part, we use very long records from tide gauge and meteorological stations located along the coastlines of Canada to determine the sea surface topography (SST), that is the departure of the mean sea level (MSL) from the equipotential surface (geode), based on the zero-frequency response (ZFR) technique. In this research, we consider that the SST is driven by atmospheric pressure and temperature as well as by wind stress. We also estimate the sea level change rate (SLCR) directly from the trend of the tide gauge records and crustal uplift rate estimates from GPS observations.;Using the above approach, we determine SST at four tide gauge stations from three oceans surrounding Canada namely, Inukjuak, QC and Churchill, MB in Hudson Bay, Victoria, BC, and Argentia, NL. The SST determined by the ZFR approach shows good agreement with the SST estimates from other geodetic models. This favourable comparison proves the effectiveness of this approach. At each station, the SLCR results are in reasonable agreement with the global average sea level rise rate (about 2 mm/a).;We design an effective Parzen low-pass filter with cut-off frequency of 0.03cph (8.33muHz) to filter and decimate the original data, we analyze the tide gauge and atmospheric time series using least squares spectral analysis, we identify unique common spectral peaks between the sea level records and each of the atmospheric effects considered in this study by applying the product spectrum approach, and we determine the ZFR by appropriate methods, e.g., frequency-dependent response (FDR) or constant response (CR). Finally, we estimate the SST by summing up the contributions from each atmospheric phenomenon. |
