MARINE CONDITIONS THERMOGRAPHS DFO

The Thermograph Network site of the Maurice Lamontagne Institute (MLI) of Fisheries and Oceans Canada (DFO) is made up of 26 stations where temperature has been recorded nearly continuously since 1993 at depths generally ranging from 1 to 30 metres, although some stations are recording at depths of 100 m or more (E.g.: Havre-Saint-Pierre and Gyre d’Anticosti). The database contains a large number of time series of water temperatures collected from various locations in the Gulf of St. Lawrence since 1979.

The “Marine Conditions” application of SLGO disseminates the thermographs data for the 2011 to 2013 period. Data prior to 2011 are available on the SLGO through the EDMS (DFO)* application.

Other than keeping track of environmental conditions, the network is used for the calibration of remote-sensing images from NOAA (National Oceanic and Atmospheric Administration) meteorological satellites. The IML remote sensing laboratory relies on two receiving stations that acquire real-time satellite images. One of the stations is located at IML while the second is at Resolute Bay.

Technical Report (PDF Format): Thermograph network in the Gulf of St. Lawrence 

History of the Thermograph Network

On the Atlantic coast, surface water temperature readings (i.e., in the top 30 metres) began to be recorded around the early 20^th century. It wasn’t until the late 1970s, however, that the Bedford Institute of Oceanography started to monitor water temperatures in the Estuary and Gulf of St. Lawrence. This program was initiated in response to requests from aquaculturists and inshore fishermen. Now, the Maurice Lamontagne Institute tracks the temperature of waters in the Gulf. Measurement stations have been set up since 1993 to more effectively monitor long-term trends in the marine environment. The data collected under this program will also be used to study short-term temperature variations in relation to tides and storms. Temperature readings can also meet more immediate needs, such as research programs on inshore fisheries or the quality of the marine environment.

Connection with remote sensing

Aside from monitoring environmental conditions, the thermograph network is used to calibrate remote sensing images derived from National Oceanic and Atmospheric Administration (NOAA) meteorological satellites. The remote sensing laboratory at the Maurice Lamontagne Institute is equipped with a receiving station that can capture this imagery in real time. This research team also requires records of the seasonal variation in sea surface temperatures to check the quality of the outputs from the satellite image analysis system. The system calculates sea surface temperature by using the algorithms developed by NOAA.These algorithms are developed based on information obtained from buoys in the ocean; however, the atmosphere above the buoys is not representative of the more continental conditions characterizing the Gulf of St.Lawrence. It is therefore important to have a precise sea surface temperature measurement network in the Gulf so comparisons can be made with the output from the image analysis system and its quality evaluated. For more reliable comparisons, readings have to be obtained from as many different regions as possible, therefore providing coverage corresponding to all the satellite-derived values. As well, the measurement sites must be located far enough from the coast to keep the satellite from confusing radiant energy emitted by shoreline with that emitted by the water surface. It is important that the results of satellite image analyses match reality as closely as possible because they are used to verify a diversity of assumptions regarding climate, including global warming.