Canadian Station Inventory and Data DownloadĬanadian tides and water level data.The yearly mean is computed from all the daily means available in each year, provided that the number of days is at least equal to 180.Ī national database of harmonic constituents for tidal stations is also maintained at MEDS in co-operation with the Canadian Hydrographic Service (CHS). The monthly mean is also computed from the hourly levels in each month, but only for months with at least 20 days of data. The daily mean is not computed if the number of observations is less than 16 per day for water level stations and 22 per day for tidal stations. Also, in some instances, the extreme daily mean will exceed the value of the recorded all time instantaneous extreme, since for very early records, daily means were recorded for a station, but instantaneous extremes were not.ĭaily and monthly means are calculated from the hourly levels.
In these instances the appropriate field(s) is filled with asterisks. 15-minute data do not carry historical datum corrections, are not quality controlled, and hence are not made generally available.įor some very early records, the instantaneous monthly extreme level is known but the exact time and/or day is not. For chart records, the monthly instantaneous extreme levels are taken directly from the chart. Hourly levels and the monthly instantaneous extreme levels are taken directly from the digital readings without averaging or interpolation. Many water level gauges record in digital format at 15-minute sampling intervals while other gauges record in analogue form on a continuous strip chart which is then digitized to hourly intervals. Original analog charts are stored on microfilm, some of which date back to the turn of the century and have not all been digitized. These data undergo two levels of quality control and are adjusted if there is a change in the reference datum at the station. Observed tidal highs and lows are also available for a limited number of years. Observed hourly heights, daily means and monthly instantaneous extremes form the basis of MEDS digital archives. Data are also exchanged annually with the Water Survey of Canada.
Observations from the CHS Permanent Water Level Network are added on a daily to monthly basis. Over 800 stations are subjected to appreciable effect of tides, and for most of these stations, the Canadian Hydrographic Service (CHS) calculates and publishes predictions of the water levels associated with the vertical movement of the tide. The number of observations spans on average 6 years per station, with 60 stations measuring water levels for over 50 years.
#Bay of fundy tidal chart archive#
The Canadian tide and water level data archive presently holds water level observations reported from over a thousand stations, with the earliest dating back to 1848. Canadian Tides and Water Levels Data Archive
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