Map showing the locations of the 12 active British Columbia lightstations featured on this page.
Last updated: Feb. 2024
Daily sea surface temperature and salinity observations have been carried out at several locations on the coast of British Columbia since the early part of the 20th century. Observations started at the Pacific Biological Station (Departure Bay) in 1914; 11 stations were added in the mid-1930s and several more in the 1960s. The number of stations reporting at any given time has varied as sampling has been discontinued at some stations and started or resumed at others.
Presently termed the British Columbia Shore Station Oceanographic Program (BCSOP), there are 12 active participating stations. Most of the stations are at lighthouses staffed by Fisheries and Oceans Canada, but three (Race Rocks, Amphitrite Point, and Active Pass) are sampled by contracted observers.
Observations are made daily using seawater collected in a bucket lowered into the surface water at or near the daytime high tide. This sampling method was designed long ago by Dr. John P. Tully and has not been changed in the interests of a homogeneous data set. This means, for example, that if an observer starts sampling one day at 6 a.m., and continues to sample at the daytime high tide on the second day the sample will be taken at about 06:50 the next day, 07:40 the day after etc. When the daytime high-tide gets close to 6 p.m. the observer will then begin again to sample early in the morning, and the cycle continues. Since there is a day/night variation in the sea surface temperatures the daily time series will show a signal that varies with the 14-day tidal cycle. This artifact does not affect the monthly sea surface temperature data.
The monthly averaged and daily SST data from all 12 currently active stations are presented on this page. These data, as well as sea-surface salinity data, can be found on Open Data and Enterprise Data Hub. More information on the program and prior analyses of its data can be found in Cummins & Masson (2014) and in Freeland (1990).
Map showing the locations of the 12 active British Columbia lightstations featured on this page.
Plot showing data availability for each lightstation on this page. Any gaps in the blue bar for each station indicate no data available for that time.
The plots below contain daily SST data from 2023. The black line shows the average of all observations for each day of the year over the entire record, subjected to a 21-day moving average to smooth the curve. The blue areas represent observations that are below average, while the red areas represent observations that are above average.
30-year climatologies of sea-surface temperature for 1991-2020, calculated from monthly mean observations.
The SST anomalies here were computed from monthly mean observations by subtracting the climatological monthly mean based on the 30 year period 1991-2020 from the raw data. The trends of the anomalies were computed from the entire series, without filling in any data gaps in the series with interpolation or otherwise. Both least-squares and Theil-Sen trends are shown in this section. Gaps in the data were filled using spline interpolation before calculating the 95% confidence intervals on the trends using the non-parametric Monte Carlo approach described by Cummins & Masson (2014)
In the following plots, the black line shows the least-squares trend for the record, which was calculated from the entire series without filling in any data gaps. The blue lines represent the lower and upper 95% confidence intervals on the trend, which were computed using the nonparametric Monte Carlo approach described by Cummins & Masson (2014). Gaps were filled using spline interpolation prior to computing the confidence intervals.
The following table lists lighthouse stations and their analysis periods and linear anomaly trends. Both least-squares and Theil-Sen trends are given and were calculated from the entire anomaly series without filling in any data gaps. New results are listed after the results of Cummins & Masson (2014) for comparison. The 95% confidence intervals accompanying each trend were computed using the Monte Carlo approach described by Cummins & Masson (2014).
As shown in the table above, both the least-squares and Theil-Sen trends for the new analysis period are statistically significant for all twelve stations. For the Cummins & Masson (2014) analysis period, only the trends for some of the stations (Amphitrite Point, Chrome Island, Entrance Island, and Race Rocks) are statistically significant. The Cummins & Masson (2014) study looked at the eight active stations having the longest records while still providing coverage of BC's coast.
The plots and tables below contain statistics on lightstation SST and were produced from daily SST data. Anomalies were computed by subtracting the average over all time for each day from the raw data.
Cummins, P. F. & Masson, D. (2014). Climatic variability and trends in the surface waters of coastal British Columbia. Progress in Oceanography, 120(2014), pp. 279–290. http://dx.doi.org/10.1016/j.pocean.2013.10.002
Freeland, H. J. (1990). Sea surface temperatures along the coast of British Columbia: regional evidence for a warming trend. Can. J. Fish. Aquat. Sci. 47: 346-350.
Data Products Team, Ocean Sciences Division
DFO.PAC.SCI.IOSData-DonneesISO.SCI.PAC.MPO@dfo-mpo.gc.ca