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| HISTORY OT THE THERMOGRAPH NETWORK |
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On
the Atlantic coast, surface water temperature readings (i.e., in the top
30 metres) began to be recorded around the early 20th 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.
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