Information identified as archived is provided for reference, research or recordkeeping purposes. It is not subject to the Government of Canada Web Standards and has not been altered or updated since it was archived. Please contact us to request a format other than those available.
PETTIGREW, B., P. LAROUCHE, D. GILBERT, 2011. Validation des images composites des températures de surface produites au laboratoire de télédétection de lInstitut Maurice- Lamontagne. Rapp. tech. can. hydrogr. sci. océan., 270, 39 p .
An entirely automated operational system having the task to produce composite images of sea surface temperature (SST) of Canadian waters has been set up at the remote sensing laboratory of Maurice Lamontagne Institute (MLI) using data from Advanced Very High Resolution Radiometer (AVHRR) sensors. In situ sea surface temperatures from six stations located in the Estuary and the Gulf of St. Lawrence have been used to validate composite images from August 1995 to August 2004. Differences over all stations between mean SST and mean in situ temperature for averaging periods of 1, 7 and 15 days were respectively -0,26 °C (1,06 °C), -0,21 °C (0,90 °C) and -0,13 °C (0,84 °C) where the values in parentheses are the standard deviations. Results showed that the accuracy of the daily mean is highly correlated to the number of measurements used to compute it. However for most validation stations, that correlation decreased rapidly for the 7 and 15 days averages. Finally, we estimated the maximum daily and weekly absolute error at the 95 % confidence level for most stations.
GALBRAITH, P.S., J. CHASSÉ, D. GILBERT, P. LAROUCHE, D. BRICKMAN, B. PETTIGREW, L. DEVINE, A. GOSSELIN, R.G. PETTIPAS, C. LAFLEUR, 2011. Physical oceanographic conditions in the Gulf of St. Lawrence in 2010 ; Conditions océanographiques physique dans le golfe du Saint-Laurent en 2010. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2011/045, 86 p .
An overview of physical oceanographic conditions in the Gulf of St. Lawrence in 2010 is presented. Air temperatures reached record highs when averaged from January to March and from October through December as well as annually. The monthly averaged freshwater runoff measured at Québec City was normal overall in 2010 but was unusually high during winter and fall, and the spring freshet was almost absent. Near-surface water temperatures in the Gulf were normal or above normal all year and in all regions except for the Mécatina Trough and Esquiman Channel in June. Maximum sea-ice volume within the Gulf and on the Scotian Shelf was 11 km³, a record low since 1969. The duration of the 2009–2010 ice season was shorter than normal and associated with the early ice melt. Winter inflow of cold and saline water from the Labrador Shelf occupied the Mécatina Trough over the entire column in winter 2010. The spread of the intrusion was confined close to the Strait of Belle Isle, leading to an overall small volume of 809 km³. However, this intrusion volume represented 29 % of the unusually small volume of mixed layer waters that were colder than -1 °C. The winter cold mixed layer volume in the Gulf, excluding the Estuary, was 13 900 km³, a value higher than the 1996–2009 average by 0.7 SD. This cold-water volume corresponded to 42 % of the total water volume of the Gulf. However, it was very warm, on average about 1 °C above the freezing point. This is the first time in 15 years of winter surveys that such high temperatures were recorded. The cold intermediate layer (CIL) index for summer 2010 was - 0.04 °C, which is similar to observations in 2000. This is an increase of 0.38 °C since 2009. On the Magdalen Shallows, none of the bottom area was covered by water with temperatures < 0 °C in September 2010, similar to conditions in 2005, 2006, 2007, and 2009. In other regions of the Gulf, very few areas had bottom temperatures below 0 °C. Regional patterns of the August and September CIL show that the layers for T < 1 °C and < 0 °C were much thinner in most parts of the Gulf in 2010 than in 2009 and had a generally higher core temperature everywhere. Conditions in March 2010 were characterized by a very thick winter mixed layer, although very warm, including a thick intrusion of Gulf waters into the Estuary. By June 2010, the CIL thickness returned to nearnormal but still had above-normal minimum temperatures. The CIL warming rate appeared to be slower than usual because core temperatures were closer to normal in certain regions by August and more so by November. The warm deep waters in the Estuary in 2009 were replaced by colderthan- normal waters by June 2010. Colder-than-normal deep waters also occupied the northwest Gulf at that time. Very warm waters occupied Cabot Strait in June at 250 m—the depth of the temperature maximum—and there is a hint that the top portion of this water mass was sampled during the March survey. The warm deep waters were still present in Cabot Strait in August as well as in November. Gulf-wide average temperatures were below normal at 200 to 300 m and salinities were below normal from 150 to 300 m. Temperatures at 300 m increased marginally overall but significantly (by 1 SD) at Cabot Strait, where the anomaly is now +1 SD. Salinity at 200 m and 300 m decreased overall by 0.6 SD but increased at Cabot Strait to reach +0.6 SD at 200 m. The 300 m waters of the Estuary are expected to cool further during the next two years, but it will be interesting to follow the warm anomaly present in 2010 at Cabot Strait as it progresses up the channel toward the Estuary. The surface mixed layer in November was anomalously thick but more importantly very warm, warmer in fact than in November 2009 which were the preconditions for the record conditions of March 2010.
GALBRAITH, P.S., R.G. PETTIPAS, J. CHASSÉ, D. GILBERT, P. LAROUCHE, B. PETTIGREW, A. GOSSELIN, L. DEVINE, C. LAFLEUR, 2010. Physical Oceanographic Conditions in the Gulf of St. Lawrence in 2009 Conditions docéanographie physique dans le golfe du Saint-Laurent en 2009. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2010/035, 77 p .
An overview of physical oceanographic conditions in the Gulf of St. Lawrence in 2009 is presented. Air temperatures were close to normal when averaged from January to March. Air temperatures were in general either normal or above normal for the remainder of the year. The monthly averaged freshwater runoff measured at Québec City was normal overall in 2009 but consisted of aboveaverage runoff in July compensated later by lower runoff in the fall. Near-surface water temperatures in the Gulf were above normal in all regions except the Northwest Gulf and the Estuary in June and in every region in August. Maximum sea-ice volume within the Gulf and on the Scotian Shelf was 65 km³, a value that is below normal using updated ice volume estimates for 1971-2000. The duration of the 2008-09 ice season was longer than normal in the Estuary, normal in the central Gulf and Cabot Strait, and shorter elsewhere. This was mostly associated with the variability of the first occurrence of ice. Winter inflow of cold and saline water from the Labrador Shelf occupied the Mécatina Trough over the entire column in winter 2009. The spread of the intrusion was confined a bit closer to the coast compared to 2008 conditions, leading to an overall smaller volume of 1270 km³, which is similar to the 2002 observations. The winter cold mixed layer volume in the Gulf, excluding the Estuary, was 14 000 km³, a value higher than the 19962009 average by 0.7 SD. This cold-water volume corresponded to 42% of the total water volume of the Gulf. The cold intermediate layer (CIL) index for summer 2009 was -0.42°C, which is similar to observations in 2002, 2004, 2005 and 2007. This is an increase of 0.32°C since 2008. On the Magdalen Shallows, almost none of the bottom area was covered by water with temperatures < 0°C in September 2009, similar to conditions in 2005, 2006 and 2007. Regional patterns of the August and September CIL show that the layers for T < 1°C and < 0°C were much thinner in most parts of the Gulf in 2009 than in 2008 and had a generally higher core temperature everywhere. In the northern Gulf, the area covered by low temperature water (< 1°C) decreased in 2009 relative to 2008 conditions. Temperatures in March 2009 were characterized by a very thick cold layer, including a thick intrusion of Gulf CIL waters into the Estuary. By June 2009, CIL temperatures returned to normal with a warming trend that continued into August, especially on the Magdalen Shallows. By OctoberNovember, CIL conditions were normal in most regions except the estuary and Northwest Gulf, where the CIL and the surface mixed layer were anomalously deep. Overall, temperature and salinity were generally normal from 150 m to 200 m, and slightly lower than normal at 250 and 300 m. Temperature and salinity at 300 m decreased for a third consecutive year, from 2008 to 2009. The lower-than-normal Gulf-wide water temperatures at 300 m were composed of normal waters in the Estuary and northwest and colder waters in the centre and coming into the Gulf at Cabot Strait. This cold anomaly has propagated inward in the last few years and is expected to continue toward the Estuary during the next few years.
GALBRAITH, P., R.G. PETTIPAS, J. CHASSÉ, D. GILBERT, P. LAROUCHE, B. PETTIGREW, A. GOSSELIN, L. DEVINE, C. LAFLEUR, 2009. Physical oceanographic conditions in the Gulf of St. Lawrence in 2008 ; Conditions docéanographie physique dans le golfe du Saint-Laurent en 2008. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2009/014, 73 p .
An overview of physical oceanographic conditions in the Gulf of St. Lawrence in 2008 is presented. Air temperatures were close to normal when averaged from January to March, contributing to an ice cover volume that was also close to the climatological mean. Air temperatures were in general either normal or above normal for the remainder of the year. The monthly averaged freshwater runoff measured at Québec City was normal overall in 2008, but consisted of above-average runoff in summer compensated later by lower runoff in the fall. The high summer runoff contributed to higher-than-normal stratification. Near-surface water temperatures were generally above normal throughout the Gulf for the months of May, July and November and were also above-normal on the Magdalen Shallows in June and in the northern Gulf from August to October. In August the northern parts of the Gulf saw positive anomalies while the southern parts experienced negative anomalies. This lead to the unusual occurrence that the waters around Prince Edward Island and in Northumberland Strait had higher temperature in July than in August 2008. On the Magdalen Shallows, a large area of the bottom was covered by water with temperatures < 0 °C in September 2008, similar to the cold period observed in the 1990s and in contrast to conditions in September 2005, 2006 and 2007 when such cold waters were not observed. Maximum sea-ice volume within the Gulf and on the Scotian Shelf was 81 km3, a value now considered about normal using updated ice volume estimates for 1971-2000. Ice first appeared early in the season and stayed later than normal (later by about 8 days later on the Magdalen Shallows). Winter inflow of cold and saline water from the Labrador Shelf occupied the Mécatina Trough from top to bottom in winter 2008. The spread of the intrusion was confined a bit closer to the coast compared to 2007 conditions, leading to an overall smaller volume of 1850 km3, which is similar to 2001 and 2006 observations. The winter cold mixed layer volume was 13 700 km3, a value higher than the 1996–2008 average by 0.8 SD, and corresponded to 41 % of the total water volume of the Gulf. The summer CIL (cold intermediate layer) index for 2008 was -0.70 °C, comparable to the very cold conditions observed in 2003 and a large decrease (by 0.47 °C) from the previous summer. Regional patterns of the August and September CIL show that the layers for T < 1 °C and < 0 °C were much thicker in most parts of the Gulf in 2008 than in 2007 and had a generally lower core temperature throughout the Gulf. In the Northern Gulf, the area covered by water of low temperature (from < -1 °C through < 1 °C) increased in August 2008 relative to August 2007. Temperatures in the water column in June 2008 were characterized by a very thick and cold CIL in most regions except the Estuary and by warm deep waters in the Estuary and the northwest Gulf. This overall pattern persisted in the August– September mean conditions. By October and into November, CIL conditions were still thick and cold, while waters above the CIL were anomalously warm. Overall, temperature and salinity were generally normal from 150 m to 300 m, with the exception of slightly lower than normal (by 0.6 SD) temperature at 150 m. Temperature and salinity in this depth range decreased for a second consecutive year. The near-normal Gulf-wide water temperatures at 300 m were composed of warmer waters in the Estuary, near-normal temperatures in the northwest and central, and colder waters flowing into the Gulf at Cabot Strait.
GALBRAITH, P.S., D. GILBERT, R.G. PETTIPAS, J. CHASSÉ, C. LAFLEUR, B. PETTIGREW, P. LAROUCHE, L. DEVINE, 2008. Physical oceanographic conditions in the Gulf of St. Lawrence in 2007 ; Conditions d'océanographie physique dans le golfe Saint-Laurent en 2007. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2008/001, 59 p .
An overview of physical oceanographic conditions in the Gulf of St. Lawrence in 2007 is presented. Air temperatures ranged from normal to cooler than normal for most of the year in the western parts of the Gulf; however, the eastern regions were only significantly cooler than normal in April and May. Averaged over the whole Gulf for the entire year, air temperature was normal. The monthly averaged runoff at Québec City was below normal during all months of 2007. Near-surface water temperatures were much cooler in 2007 overall than in 2006 in all regions of the Gulf. Near-surface waters were warm in the St. Lawrence Estuary in January and February. Summer maximum surface temperatures occurred earlier than usual, followed by earlier-than-usual cooling. Surface temperatures were generally below normal for the rest of the year except for October in the Estuary. On the Magdalen Shallows, there was (almost) no bottom area covered by water with temperatures <0 °C in September 2007. Maximum sea-i ce volume within the Gulf and on the Scotian Shelf was below normal but still much higher than the volume recorded in 2006. Winter inflow of cold and saline water from the Labrador Shelf occupied the Mecatina Trough from top to bottom. The spread of the intrusion had an area similar to that of 2006, but its volume was much larger and similar to that observed in 2004. The winter cold mixed layer volume was 13100 km3, slightly above the 1996-2007 average, and corresponded to 39 % of the total water volume of the Gulf. The higher winter volume of cold water compared with 2006 conditions led to a decrease of 0.44 °C in the Cold Intermediate Layer (CIL) index, reaching -0.23 °C in summer 2007, which is comparable to conditions observed in 2004. The index saw a large decrease after three consecutive years of warming. Regional patterns of the CIL show that the layer for T < 1 °C and < 0 °C was much thicker in the northern half of the Gulf in 2007 than in 2006 and had a generally lower core temperature almost everywhere as well. Seasonal and regional patterns of water column temperatures in June were generally close to the 1971-2000 climatology at all depths, except for the very thick and cold CIL in the Anticosti Channel and warm deep waters in the northwest. This overall pattern persisted from August to September, but by late fall conditions were about normal everywhere except for the anomalously warm nearsurface mixed layers in the northwest and warm near-surface waters on the Magdalen Shallows and in Cabot Strait. Averaged annually for the entire Gulf, the temperature and salinity from 150 m to 300 m were normal in 2007. Spatially, at 300 m, this was composed of warmer than normal waters near the Estuary, near-normal temperatures in the centre and colder than normal waters coming into the Gulf at Cabot Strait. The outlook for 2008 from the March 2008 survey is for a slight cooling of the CIL index to -0.47 °C resulting from a thicker cold winter surface layer.
GALBRAITH, P.S., D. GILBERT, C. LAFLEUR, P. LAROUCHE, B. PETTIGREW, J. CHASSÉ, R.G. PETTIPAS, W.M. PETRIE, 2007. Physical oceanographic conditions in the Gulf of St. Lawrence in 2006 ; Conditions d'océanographie physique dans le golfe Saint-Laurent en 2006. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2007/024, 51 p .
An overview of physical oceanographic conditions in the Gulf of St. Lawrence in 2006 is presented. Air and surface water temperatures were above normal except for late summer in most parts of the Gulf. Bottom water temperatures on the Magdalen Shallows were unusually warm; no observations below 0 °C were recorded in September. The yearly total freshwater runoff at Québec City was normal but included an anomalous strong fall peak. Sea ice coverage and volume within the Gulf during the winter was the lowest recorded since 1969. The winter cold mixed layer volume was the smallest recorded in the 11 year history of the winter helicopter survey and corresponded to 29 % of the total water volume of the Gulf. This shallow winter mixed layer led to the CIL index for summer 2006 increasing to +0.21 °C. This is the warmest value since 1983, but only 0.1 °C warmer than in 2000 which was the second warmest. Regional patterns of the CIL minimum temperatures show that increases between 2005 and 2006 were more pronounced in the Laurentian Channel than elsewhere. The minimum temperature actually decreased in Mecatina Trough, presumably due to the increased inflow of a thick layer of cold and highly saline water, which was observed from the annual March survey, through the Strait of Belle Isle. Regional patterns similar to those found for the CIL minimum temperatures were seen in the regional CIL thickness distribution. The CIL volume (T <1 °C) for the Magdalen Shallows during the September groundfish survey was the lowest since 1982. Water temperatures were generally one standard deviation above the mean, based on the 1971-2000 climatology at all depths for most of the year. Exceptions to this included the CIL in Esquiman Channel and Mecatina Trough and the deeper waters (>300 m) of the southern half of the Laurentian Channel which were colder. The most noteworthy thermal features in November were the anomalously deep CIL in the Estuary and northwestern Gulf regions and the anomalously warm waters above the CIL everywhere in the Gulf. The outlook for 2007 based on the March 2007 survey is for a 0.6 °C cooling of the summer CIL index forecast from a thicker winter cold surface layer and increased inflow of Labrador Shelf water through the Strait of Belle Isle.
GILBERT, D., P.S. GALBRAITH, C. LAFLEUR, B. PETTIGREW, 2004. Physical Oceanographic Conditions in the Gulf of St. Lawrence in 2003 ; Conditions docéanographie physique dans le golfe Saint-Laurent en 2003. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2004/061, 63 p .
An overview of physical oceanographic conditions in the Gulf of St. Lawrence in 2003 is presented. Air temperatures and surface water temperatures were below normal in winter and above normal in the fall. During winter 2003, sea ice coverage within the Gulf was about 10 % above the long-term mean, the first year above normal since 1995. But of more significance, a record amount of ice was advected out of the Gulf through Cabot Strait during winter 2003, and the total volume of ice formation in the Gulf was much higher than normal. Moreover, the inflow of water through the Strait of Belle Isle in the northeast Gulf was by far the largest one observed over the 9-year period of helicopter CTD surveys conducted in March. This inflow of cold and salty water from Belle Isle Strait together with the large amount of ice produced in the Gulf in the winter of 2003 caused a huge increase in the summertime thickness and volume of T < 0 °C waters (+300 %) and T < 1 °C waters (+40 %) relative to 2002. This was accompanied by a 0.65 °C drop in the cold intermediate layer minimum temperature index which is now 0.54 °C below the 1971-2000 normal conditions and the fifth coldest in 57 years. The annual mean runoff of the St. Lawrence River at Québec City was 13.4 % below normal. This led to above normal surface salinities and below normal surface layer stratification during most of 2003. In the 30-100 m layer, the 2003 temperature was colder than normal while salinity was higher than normal. In the 100-200 m layer, the 2003 temperature was colder than normal but salinity was close to normal. Finally, in the 200-300 m layer, both temperature and salinity were close to normal. The 2003 annual mean oxygen concentration in the bottom waters (≥ 300 m) of the Lower St. Lawrence Estuary (18.3% saturation) was the second lowest ever observed.
LAROUCHE, P., B. PETTIGREW, R. PIGEON, 2003. Optical buoy network in the St. Lawrence Estuary and Gulf. Pages 1-13 in Larouche P., B. Pettigrew & R. Pigeon. Seventh International Conference on Remote Sensing for Marine and Coastal Environments, Miami, 20-22 May 2002 .
LAROUCHE, P., B. PETTIGREW, 2003. Oceanographic buoy network in the Gulf of St. Lawrence. AZMP Bull. PMZA, 3: 42-45 .
[Abstract only available in French]
Le Laboratoire de Télédétection de l'Institut Maurice-Lamontagne reçoit et traite des images NOAA-AVHRR et SeaWiFS afin dutiliser la couleur et la température de surface de leau comme outils de suivi de lenvironnement. Pour ce faire, des algorithmes standards développés à laide de données océanographiques sont utilisés. Cependant, lutilisation de ces algorithmes pour les eaux des mers intérieures comme celles du golfe du Saint-Laurent et de la baie dHudson cause problème puisque ces environnements sont fortement influencés par de forts débits deau douce qui transportent avec eux une grande quantité de matières organiques particulaires et dissoutes qui ont une influence significative sur les mesures de télédétection. De plus, latmosphère au-dessus de ces mers intérieures est influencée par des aérosols de type continentaux, ce qui affecte la qualité des mesures. Il est donc très important de pouvoir valider ces algorithmes avec des mesures de terrain et/ou encore, den développer de nouveaux qui sont mieux adaptés aux conditions particulières des régions sous forte influence des débits deau douce. Nous avons entrepris un tel projet dans le golfe du Saint-Laurent avec laide de lAgence Spatiale Canadienne. Comme la fréquence déchantillonnage (toutes les deux semaines) aux stations fixes du Programme de Monitorage de la Zone Atlantique (PMZA) nest pas bien adaptée à ce type de travail de validation dimages satellites, nous avons opté pour le développement dune nouvelle bouée océanographique qui permettrait dobtenir des mesures de terrain en temps réel. Nous avons donc décidé de mettre en place un réseau dobservation du Saint-Laurent composé, dans un premier temps, de 3 bouées localisées dans des régions très différentes de lécosystème du Saint-Laurent (lestuaire, le sud et le nord-est du Golfe). Laccès en temps réel aux résultats des bouées peut se faire en consultant ladresse Internet suivante: www.osl.gc.ca. Dans le présent article, nous décrivons le projet plus en détail et nous présentons quelques résultats provenant des deux premières années déchantillonnage de la bouée mouillée à la station de Rimouski (IML-4). Ces résultats indiquent quil existe une relativement bonne concordance entre les données provenant de la bouée et celles provenant du monitorage régulier à cette station pour le suivi de la variabilité saisonnière. Toutefois, les données de la bouée indiquent également quil existe une grande variabilité à plus courte échelle de temps et quil est possible de détecter des événements océanographiques importants qui peuvent passer complètement inaperçus à léchelle de temps du monitorage régulier (deux semaines). En plus de contribuer au monitorage environnemental, les données obtenues par les bouées océanographiques peuvent aussi servir à des projets de recherche scientifique de nature plus fondamentale. Par exemple, les données optiques obtenues indiquent quil pourrait être possible de développer un algorithme utilisant des données de télédétection de couleur de la mer pour mesurer la salinité dans les milieux possédant de forts gradients horizontaux. La mise en place de notre réseau de bouées nest pas encore terminée. Nous comptons ajouter une seconde bouée en 2004 à la station de monitorage de Shédiac (sud du golfe, IML-6) et une troisième bouée est prévue pour 2005 à la station du Banc Beaugé (nord-est du golfe, IML-2). Il convient en terminant de noter quil sera facilement possible dintégrer de nouveaux senseurs aux bouées de base afin de les rendre plus polyvalentes et ainsi participer encore plus fortement aux activités du PMZA.
GILBERT, D., A.F. VÉZINA, B. PETTIGREW, D.P. SWAIN, P.S. GALBRAITH, L. DEVINE, N. ROY, 1997. État du golfe du Saint-Laurent : conditions océanographiques en 1995. Rapp. tech. can. hydrogr. sci. océan., 191, 113 p .
We present an overview of the oceanographic conditions in the Gulf of St. Lawrence for 1995. The highlights are that 1) winter air temperatures were near normal in the western Gulf, but were close to 2 °C below normal in the eastern Gulf; 2) the summer was warm and dry in the western Gulf; 3) the ice cover was slightly above normal, with more severe ice conditions in the northeastern Gulf than in the western Gulf; 4) the core temperature of the cold intermediate layer was colder than normal; 5) the bottom area with a temperature below 0 °C reached a record high in the southern Gulf; 6) the deep layers cooled relative to 1994, and the cooling was more intense in he 100-200 m layer (O.9 °C) than in the 200-300m layer (0.3 °C); 7) the dissolved oxygen content of the 200-300 m layer was slightly below the 1981-1995 average in the Cabot Strait and Honguedo Strait sections; 8) the distribution of chlorophyll and nitrate in the surface layer corresponded roughly with the patterns inferred from historical data, i.e. a gradient of decreasing biomass from the West and south towards the east and north that is strongly inversely correlated with salinity; 9) in Northumberland Strait, the concentrations of chlorophyll near the bottom were much higher than elsewhere.
GILBERT, D., B. PETTIGREW, 1997. Interannual variability (1948-1994) of the CIL core temperature in the Gulf of St. Lawrence. Can. J. Fish. Aquat. Sci., 54 (Suppl. 1): 57-67 .
The interannual variability (1948-1994) of the cold intermediate layer(CIL), defined here as the layer with T < 3 °C, was investigated for 6 subregions of the Gulf of St. Lawrence. First a mean annual cycle of CIL properties was calculated for the 6 subregions(the Estuary, the Northwest, Northeast, Central, and Southern Gulf, and Cabot Strait). The midsummer warming rates thus obtained were then used to construct time series of the CIL core temperature extrapolated to July 15, using all available data from May 1 to September 30 of each year. The important result is that the mid-summer CIL core temperature was below normal from 1986 to 1994, this cold period being most intense from 1990 to 1994. The time series of CIL core temperature was correlated with average winter air temperatures from several weather stations inside and outside the Gulf to try to distinguish between local and remote atmospheric forcing and obtained the highest correlations with weather stations from the west coast of Newfoundland.
The authors present an overview of the physical oceanographic conditions in the Gulf of St. Lawrence for 1994, with special emphasis on the temperature and salinity profiles collected furing the August-September 1994 shrimp and groundfish survey. The main highlights for 1994 are that 1) winter air temperatures were below the 1961-1990 normal for the sixth consecutive year, 2) the ice cover was above the 1962-1987 median areal extent, 3) the cold intermediate layer was colder than normal for the ninth consecutive year, 4) intense upwelling occurred along Quebec's north shore during the month of August, as evidenced by the very cold surface temperatures, and 5) the deep layers (100-200 m and 200-300 m) warmed in the Gulf, except in Cabot Strait where the temperatures dropped by about 0.5 °C.
GILBERT, D., B. PETTIGREW, 1996. Variations de la couche froide intermédiaire du golfe du Saint-Laurent de 1948 à 1995. Naturaliste can., 120(2): 69-70 .
LAFLEUR, C., B. PETTIGREW, A. ST-HILAIRE, D. BOOTH, E.M. CHADWICK, 1995. Seasonal and short-term variations in the estuarine structure of the Miramichi. Pages 45-71 in E.M.P. Chadwick (ed.). Water, science and the public : the Miramichi ecosystem. Dept. of Fisheries and Oceans (Can. Spec. Publ. Fish. Aquat. Sci., 123) .
GRATTON, Y., B. PETTIGREW, B. PELCHAT, D. GILBERT, M. COUTURE, J. LANDRY, 1994. Overview of the environmental conditions in the Gulf of St. Lawrence in 1993. DFO, Atlantic Fisheries, Research Document, 94/55, 45 p .
GILBERT, D., B. PETTIGREW, 1993. Current-meter data from Bonne Bay, Newfoundland, during the summer of 1991. Can. Data Rep. Hydrogr. Ocean Sci., 122, 63 p .
During the summer of 1991, eleven current-meters were deployed at four mooring sites near the mouth of Bonne Bay, a fjord on the west coast of Newfoundland. The means and standard deviations of the time series of temperature, salinity, density, and velocity components are given here, together with the main tidal constants obtained from harmonic analysis of the currents. Each time series and its corresponding low-passed time series are plotted. Wind data from Daniel's Harbour, located 80 km northeast of Bonne Bay, are also shown for comparison with the current-meter data.
PETTIGREW, B., P. LAROUCHE, 1992. Données courantométriques et météorologiques dans le sud-est de la baie d'Hudson durant l'hiver 1986. Rapp. stat. can. hydrogr. sci. océan., 113, 87 p .
Oceanographic and meteorological data were taken during the winter of 1986 in southeastern Hudson Bay between the Great Whale River mouth and Belcher islands. These measurements were part of a study to understand the influence of the atmospheric pressure gradient on the evolution of the Great Whale River plume. Data from current meters (current, temperature and salinity) and from a meteorological station (winds, atmospheric pressure, solar radiation and relative humidity) are presented in this report. A statistical analysis of current meter data, a harmonic tidal analysis and a spectral analysis of current components are also included. (DBO).
An oceanographic study was conducted in Havre de Gaspé during the spring and early summer of 1990. The aims were twofold : 1) to describe the physical oceanographic conditions during this period, and 2) to examine the exchange between the Havre and bay outside with a view to evaluating the potential for influx of toxic algae. The report presents time series of data from moored current meters, a tide gauge, and a meteorological station, plus profile STD data and Lagrangian displacements of drogued buoys.
- Date modified: