Relationship between the Atlantic Multidecadal Oscillation index and variability of mean annual flows for catchments in the St. Lawrence watershed (Quebec, Canada) during the past century

2010 ◽  
Vol 41 (2) ◽  
pp. 115-125 ◽  
Author(s):  
Ali A. Assani ◽  
David Landais ◽  
Mhamed Mesfioui ◽  
Martin Matteau

This paper, based on an analysis of the mean annual flow (MAF) of 16 natural rivers over the period 1934–2000, has the following goals: (1) to determine the different temporal variability modes of the MAF in the St. Lawrence watershed, (2) to describe the temporal variability of the streamflow in each mode and (3) to analyze the influence of the AMO (Atlantic Multidecadal Oscillation) on the interannual and interdecadal variability of mean annual flows in this Quebec watershed. This paper shows that the interannual variability of mean annual flow was not synchronous on both sides of the river. During the period analyzed, MAF variability was characterized by a tendency to decrease on the south shore (right bank) but to increase on the north shore (left bank). A correlation analysis reveals that the influence of the AMO was limited exclusively to the north shore of the river, which is characterized by a continental climate. This correlation is negative. On the south shore, streamflow is correlated negatively to the AO (Arctic Oscillation).

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3487
Author(s):  
Ali Arkamose Assani ◽  
Ayoub Zeroual ◽  
Alexandre Roy ◽  
Christophe Kinnard

Several statistical methods were used to analyze the spatio-temporal variability of daily minimum extreme flows (DMEF) in 17 watersheds—divided into three homogenous hydroclimatic regions of southern Quebec—during the transitional seasons (spring and fall), during the 1930–2019 period. Regarding spatial variability, there was a clear difference between the south and north shores of the St. Lawrence River, south of 47° N. DMEF were lower in the more agricultural watersheds on the south shore during transitional seasons compared to those on the north shore. A correlation analysis showed that this difference in flows was mainly due to more agricultural areas ((larger area (>20%) on the south than on the north shore (<5%)). An analysis of the long-term trend of these flows showed that the DMEF of south-shore rivers have increased significantly since the 1960s, during the fall (October to December), due to an increase in rainfall and a reduction in cultivated land, which increased the infiltration in the region. Although there was little difference between the two shores in the spring (April to June), we observed a decrease in minimum extreme flows in half (50%) of the south-shore rivers located north of 47° N.


1969 ◽  
Vol 6 (4) ◽  
pp. 771-774 ◽  
Author(s):  
Douglas S. Rankin ◽  
Ravi Ravindra ◽  
David Zwicker

Previous work in the Gulf of St. Lawrence has yielded an unusually high upper-mantle compressional velocity. In the Gaspé area a more recent determination has yielded a value of 8.75 ± 0.20 km/s for an unreversed profile. The arrival time at a station on the north shore of the St. Lawrence River suggests that there is no major difference in velocity and depth relative to the south shore.


2010 ◽  
Vol 31 (1-2) ◽  
pp. 61-80 ◽  
Author(s):  
Jean-Claude Dionne

The Goldthwait Sea is defined as the late- and post-Glacial marine invasion in the St. Lawrence Estuary and Gulf east of Québec City. In Québec, this sea has submerged an area of about 25 000 km2. The largest areas submerged are the north shore of the St. Lawrence between Les Escoumins and Blanc-Sablon, the south shore between Levis and Tourelles, and the Anticosti Island. The upper limit of the Goldthwait Sea varies from place to place. The Goldthwait Sea began 14 000 years ago and land emergence is still in progress, since the pre-Wisconsin marine level has not been recovered yet. For a better chronology, this long interval needs to be subdivided. Three main periods have been recognized: Goldthwaitian I, II and III. However, a geographical subdivision is also needed. Numerous shorelines were observed at various elevations throughout the area formely submerged by the Goldthwait Sea. However, only a few shorelines are well developed and extensive, and correlations between former shorelines are difficult to establish. Only three levels are widespead and common to the Estuary and parts of the Gulf. The isostatic recovery has been rapid during the first three thousand years after déglaciation of the area: about 75%.


1954 ◽  
Vol 11 (3) ◽  
pp. 198-260 ◽  
Author(s):  
A. G. Huntsman ◽  
W. B. Bailey ◽  
H. B. Hachey

Hydrographic data for late August, 1923, show for the Strait (a) progressive inward movement on the north side of Arctic or sub-Arctic water, (b) progressive outward movement on the south side of Gulf water and (c) a dominant outward flow with evidence of a previous dominant inward flow. Time differences suggest tidal causes for the marked temperature and salinity changes. Current measurements for a double tidal period indicate residual trends of nine and eight miles per day in opposite directions on the north and south sides of the Strait. Inside, the Esquiman Channel shows two contra-clockwise eddies north and south of the Mekattina Bank. In addition, hydrographic data show a strong northeasterly movement along the Newfoundland shore and a weaker southwesterly one along the opposite Quebec shore.Planktonic animals indicate the water movements, Mertensia, Acartia spiniremis, Themisto, Pseudalibrotus and Oikopleura vanhöffeni surviving to various degrees in the water from the Labrador Current that reaches the centre of the Gulf along the north shore of the Strait and Channel. Other forms characterize the warm shallow water along the Newfoundland shore inside the Strait and show its movement outward to the east coast of Newfoundland. The Greenland seal fishery of winter reflects the inward movement from the Labrador Current. Cod and herring fisheries invade this cool water of the north shore only locally in summer with access of warmer water from the south shore. Lobsters and cunners are very abundant in, but particularly confined to, the warm shallow water mentioned above.


1977 ◽  
Vol 14 (10) ◽  
pp. 2284-2293 ◽  
Author(s):  
D. J. Hearty ◽  
R. F. Mereu ◽  
C. Wright

A temporary seismic network located in the La Malbaie region of eastern Quebec during the summer of 1974 for studying the local seismicity of the area was used as a seismic array to measure directly the slowness and azimuth of the P arrivals from 18 teleseismic events. A consistent bias in the arrival vectors was observed for rays approaching the array from the south (i.e. azimuths 181°–227°). This bias can be explained by a thickening of sedimentary strata beneath the south shore of the St. Lawrence River as opposed to the outcropping Precambrian basement rock on the north shore. The sedimentary accumulation can be interpreted in terms of a sloping interface located under the network between sediments and Precambrian rock or a thick horizontal sedimentary layer underlying the south shore of the St. Lawrence River.


1851 ◽  
Vol 2 ◽  
pp. 10-12
Author(s):  
J. A. Broun

The observatory is situated on a rising ground forming the left bank of the Tweed, and is at a distance of about fifty yards from the Astronomical Observatory. It is built of wood; copper nails were used, and all iron carefully excluded from the building.The plan of the observatory is rectangular, 40 feet long by 20 broad: It is divided into one large room to the north, 40 feet by 12, and two ante-rooms to the south, with the lobby and entrance doors between.


Traditio ◽  
1953 ◽  
Vol 9 ◽  
pp. 213-279 ◽  
Author(s):  
Giles Constable

The years between 1146 and 1148 were signalized in the annals and chronicles of Medieval Europe by Christian campaigns on all fronts against the surrounding pagans and Moslems. The most important of these was directed towards the Holy Land, against the Moslems, who had recently seized Edessa. It consisted of no less than five expeditions. The two largest armies, commanded by the Emperor Conrad III and King Louis VII of France, followed the same route overland across the Balkans to Constantinople; both met with crushing defeats in Asia Minor and finally reached the Holy Land, as best they could, by land and sea. A third force, under Amadeus III of Savoy, moved down Italy, crossed from Brindisi to Durazzo, and joined the army of Louis at Constantinople late in 1147. In August of the same year a naval expedition led by Alfonso of Toulouse left the South of France and arrived in Palestine probably in the spring of 1148. At the same time, a joint Anglo-Flemish naval force sailed along the north coast of Europe, assisted the King of Portugal in the capture of Lisbon, proceeded around the peninsula early in 1148, attacked Faro, and presumably reached the Holy Land later that year. Meanwhile, in the northeast, four armies co-operated in a campaign against the pagan Wends across the river Elbe: a Danish army joined the Saxons under Henry the Lion and Archbishop Adalbero of Bremen in an attack on Dubin; another, larger, army led by Albert the Bear of Brandenburg and many other temporal and spiritual lords advanced against Demmin and Stettin; a fourth expedition, finally, under a brother of the Duke of Poland attacked from the southeast. In 1148, on the south shore of the Mediterranean, a powerful fleet under George of Antioch extended the control of Roger II of Sicily over the entire littoral from Tripoli to Tunis. In the West, four campaigns were directed against the crumbling power of the Almoravides. The Genoese in 1146 sacked Minorca and besieged Almeria. During the following year, the Emperor Alfonso VII of Castile advanced south through Andalusia and captured Almeria with the aid of a strong Genoese fleet, which in 1148 sailed north and joined the Count of Barcelona in his campaign against Tortosa. In the previous year, Alfonso Henriques of Portugal had captured Santarem and secured the assistance of the Anglo-Flemish fleet for an attack on Lisbon, which fell late in 1147.


1989 ◽  
Vol 26 (12) ◽  
pp. 2710-2717 ◽  
Author(s):  
John D. Greenough ◽  
Lois M. Jones ◽  
David J. Mossman

Early Jurassic quartz-normative tholeiitic basalts occur in a series of fault blocks at four localities (Cap d'Or, Parrsboro, Five Islands, and Bass River) along the north shore of the Bay of Fundy. Major-element and trace-element data show that they represent outliers of the North Mountain basalt (NMB), which from the south shore of the Bay of Fundy are well-known. Diagnostic 87Sr/86Sr ratios (≈0.70609) indicate that a thick (>90 m) flow at Five Islands and Cap d'Or represents the lower unit of NMB, thus extending this single flow's lateral extent to 230 km. Thin flows overlying the thick flow at Cap d'Or suggest that the middle unit of NMB also occurs on the north shore. A thick flow at McKay Head (Parrsboro area) shows a variable Sr isotopic composition that is probably a result of metasomatism (with Rb addition) along the Cobequid fault. The average composition (0.70656) is similar to that of the upper unit of NMB. If the flow does represent the upper unit, then four thinner flows above it form an "overlying unit" not recognized along North Mountain. Although the nature of contacts between the middle and upper units was not observed, a lack of sedimentary rocks between all other flow units indicates that little or no sedimentation occurred between basalt eruptions. North shore basalts appear less mafic (more evolved) than south shore basalts, providing support for the hypothesis of differentiation during northeasterly magma migration through dykes that fed 230 km long fissure eruptions.


2008 ◽  
Vol 21 (5) ◽  
pp. 1104-1121 ◽  
Author(s):  
Sergey Kravtsov ◽  
Christopher Spannagle

Abstract This study identifies interdecadal natural climate variability in global surface temperatures by subtracting, from the observed temperature evolution, multimodel ensemble mean based on the World Climate Research Programme's (WCRP) Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset. The resulting signal resembles the so-called Atlantic multidecadal oscillation (AMO) and is presumably associated with intrinsic dynamics of the oceanic thermohaline circulation (THC). While certain phases of the oscillation are dominated by the anomalies in the North Atlantic region, other phases are characterized by global teleconnections to the North Pacific Ocean, tropical Atlantic Ocean, as well as the Southern Ocean. In particular, natural variability of sea surface temperature in the Atlantic hurricanes’ main development region has a peak-to-peak amplitude comparable in magnitude to this region’s surface temperature increase over the past century, for all seasons. Evidence suggests that the AMO influence on secular trends in the global-mean surface temperature can arise via direct, regional contribution to the surface temperature evolution, as well as via an indirect route linked to variability of the oceanic uptake of CO2 associated with AMO-related THC changes.


1839 ◽  
Vol 129 ◽  
pp. 151-161 ◽  

In former communications to the Society, the laws of high water at Plymouth and other places have been the subject of my researches. These being obtained, the laws of low water are a subject of importance and interest on many accounts. The first ground of my pursuing this subject was the desire to ascertain how far the mean water , that is, the height midway between high and low water, is permanent during the changes which high and low water undergo. That it is approximately so at Ply­mouth, had been ascertained both by Mr. Walker and myself, by means of a com­parison of a short series of observations. But it was desirable to know with more exactness what was the real amount of this permanency, when, by using a long series of observations of high and low water, the irregularities arising from accident, and from taking imperfect cycles of inequalities, were eliminated. There was another reason which made this inquiry important at the present time. An operation has been recently carried on by the direction and at the expense of the British Association, with a view of ascertaining what surface ought to be taken as the permanent level of the sea. A Level Line has been carried with great care and accuracy from the north shore of Somerset to the south shore of Devon ; and the po­sition of this line has been fixed, so as to be recognised at any future time, by means of marks at Axmouth, at East Quantockshead, at Stolford, and at Portishead. This line has also been referred to the sea at its extremities ; and the observations show that the height of mean water coincides, at least very nearly, at different places, as well as at the same place at different times. While the difference of levels of low water at Axmouth on the English Channel, and Wick Rocks on the Bristol Channel, is not less than twelve feet; the mean water at those two places coincides in level within a few inches. In order to determine further what accuracy may be attained in this result, we are led to inquire what is the degree of permanency at one place. I may further add, that it cannot but be instructive to know how far the corrections of the height and time of low water, for lunar parallax and declination, agree in form and amount with the same corrections already obtained for high water.


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