Comparison of Interannual Variability Modes and Trends of Seasonal Precipitation and Streamflow in Southern Quebec (Canada)

Abstract

The interactions between precipitation, streamflow and groundwater are very complex. In cold temperate regions characterized by harsh winters, winter streamflow is mainly derived from aquifers that are recharged in the spring, during snowmelt, and in the fall, when evapotranspiration is subdued. Despite this complexity, the modes and trends in the interannual variability of spring (April, May, June and July) streamflow and fall (August, September, October and November) precipitation and streamflow were compared to the modes and trends in the interannual variability of winter (December, January, February and March) streamflow in southern Quebec from 1950 to 2000. Results indicate that the variability modes are identical for all four of these hydro‐climatic variables: two modes (south‐east and east modes) on the south shore of the St. Lawrence River on either side of the 47°N and a single mode (south‐west mode) on the north shore. As for the trend, a significant increase in winter streamflow was observed on the north shore. This increase is comparable to that observed in spring streamflow, which suggests that winter streamflow on the north shore is mainly derived from groundwater recharge during the spring. Moreover, both spring and winter streamflows are positively correlated to the North Atlantic Oscillation climate index. On the south shore, south of the 47°N, a significant decrease was observed in the trend of the interannual variability of winter streamflow, this in spite of a significant increase in fall precipitation and streamflow. An increase in evaporation (decreased infiltration) due to a shift from forest cover to agricultural land cover in this region could account for this. However, fall precipitation and streamflow and winter streamflow are significantly correlated to the Atlantic Multidecadal Oscillation winter index. This correlation is negative with the first two variables but positive with the third. This study suggests that, in southern Quebec, the interannual variability of winter streamflow is mainly affected by spring recharge in non‐agricultural catchments (east and south‐west modes) and by farming in agricultural catchments (south‐east mode). Copyright © 2011 John Wiley & Sons, Ltd.

Temporal Regionalization of 7-Day Low Flows in the St. Lawrence Watershed in Quebec (Canada)

“…Zhang et al (2000) showed that fall precipitation has significantly increased in the last century. This was confirmed by Assani et al (2011) in Québec, who showed that this increase in precipitation (from August to November) was statistically significant only in the Southeast Mode. Hence, the increase in winter 7-day low flow in this mode (Southeast) can only be due to increasing rainfall during the fall.…”

Climate variability in the subarctic area for the last 2 millennia

“…In the North Atlantic sector, instrumental sea surface temperature (SST) variations since AD 1860 highlight low-frequency oscillations known as the AMO (Kerr, 2000). The AMO corresponds to the alternation of warm and cool anomalies, which have a considerable impact on the regional climate over the Atlantic, North America and western Europe (e.g., Enfield et al, 2001;Sutton and Hodson, 2005;Knight et al, 2006;Assani et al, 2011). In the North Pacific, the PDO drives the multidecadal variability (Mantua et al, 1997).…”

Relationship between water color, water levels, and climate indices in large rivers: Case of the St. Lawrence River (Canada)

“…The influence of this index on the interannual variability of hydroclimatic variables (temperature, precipitation, and river flow) is largely documented in North America [e.g., Enfield et al, 2001;McCabe et al, 2004;Sutton and Hodson, 2005;Curtis, 2008]. For instance, this index revealed a negative correlation with Assani et al, 2010aAssani et al, , 2010bAssani et al, , 2011Assani et al, , 2012. Accordingly, when this index is in a positive phase, precipitation and river flow (water level) diminished.…”