Temperature data has been collected at the Saanich Inlet location since February 2006. For the daily plot above, each day is compared with daily mean data collected from 2006-2016. The figure below shows a more detailed plot of the last week. This plot is generated by calculating the historical daily mean since 2006 for each of the last seven days and plotting the data against that daily mean to highlight current anomalies in the data. The historical maximum, minimum and standard deviation are shown on the plot as well.

For more information on Saanich Inlet and to view the complete dataset, see here.

Different classes and sizes of vessels, for example recreational fishing vessels, tugs, or cargo ships, produce different amounts of noise. Ocean Networks Canada, working with Vancouver Fraser Port Authority and JASCO Applied Sciences, has been recording vessel noise with an Underwater Listening Station (a specialized hydrophone array) in a shipping lane in the Strait of Georgia in order to better understand and quantify ship noise.

As each vessel passes the Underwater Listening Station, the underwater radiated noise level (RNL) is measured. Eventually, the system will have a database of individual ship noise levels for most vessels using the Salish Sea waterways. In the short term, to estimate an RNL for all vessels (measured and unmeasured), the average RNL for each type of vessel (tug, tanker, etc.) has been determined from the September 2015 to September 2016 dataset.

To calculate the monthly Salish Sea sound level, the number of vessels of each type within the Salish Sea region (shown on the map below) is counted every day. The daily noise contribution by vessel type is computed by multiplying the daily number of vessels of each type by the average RNL for that type (in power units of µPa2). The total daily average noise power is then calculating by adding up the contributions from all vessel types for that day. The average daily noise for a given month can be similarly calculated by adding the daily noise power for all vessel types for the entire month and dividing by the number of days in the month.

When converted to decibels (dB), this acoustic noise index provides a measure of the region’s average daily loudness, with higher numbers representing louder sound levels. The index in dB is a logarithmic measure (similar to how animals, including humans, perceive loudness). Each 3 dB increase represents a doubling of the acoustic power.