Development of the regional climate profile of Nunavik

The northern territory of Quebec has considerable development potential that is susceptible to being exploited in the coming decades. In order to properly guide these economic activities and the infrastructure supporting them, it is important to understand and characterize the current regional climate and its evolution. The identification and analysis of climate-related vulnerabilities as well as the search for solutions allowing to adapt to climate change require data on the baseline climate and future climate. However, the availability of observed climate series over sufficiently long time periods and that are well distributed across northern Quebec is a major challenge. One way to compensate for the scarcity of observations is to resort to alternative datasets. The analysis and comparison of these datasets will allow a better understanding and characterization of the baseline climate of the Nunavik region.

• Improve the level of knowledge of the Nunavik climate and its spatial and temporal variability to support the identification and analysis of vulnerabilities.

• Provide maps and summary tables of the baseline climate for different indicators.

• Explore the potential of alternative datasets (reanalyses) for the estimation of extreme rainfall quantiles.

• Comparison of various datasets drawn from gridded observations and reanalyses with observation station data available from the MDDELCC network.

• Identification of one or more datasets that lend themselves to characterizing the baseline climate and its variability in time and space.

• Production of maps in GIS format and summary tables of the climate indicators of interest.

• Reassessment of the distribution of the types of climates and bioclimates north of the 55^th parallel, in collaboration with the MDDELCC.

• Identification of reanalyses able to reproduce precipitation extremes in the North.

The results demonstrate that reanalyses offer a certain advantage over other types of datasets when calculating
indicators and producing maps for the Nunavik. In total, more than a hundred indicator maps were produced and the evolution of these indicators was estimated. The following findings were reported for temperature, precipitation, growing season and snow cover.

Average annual temperatures present a north-south gradient in all reanalyses, with temperatures in the order of -8 to -10°C in northern Nunavik and -2 to -4°C for the south of the territory. The evolution of average temperatures shows a general upward trend for annual and monthly temperatures in Nunavik between 1981 and 2010.

Figure 1. Classification of bioclimates established on the average climate of four reanalyses (ERA-Interim, SFAF, JRA55, MERRA) available on a 50-km grid. The classification follows the criteria established by Litynski as presented in Gerardin and McKenney (2001).

Total annual precipitation exhibits a gradient similar to that of temperatures, with higher values in the south, in the order of nearly 1000 mm and 450−500 mm in the north. Note that total precipitation is higher in summer and fall months than during winter and spring months. With respect to the evolution of total precipitation, the results suggest an increase across the entire territory for the 1981−2010 period.

The growing season was shown to be longer in the southeast, near James Bay, with about 160 to 170 days, and much shorter in the north, where it ranged between 80 to 90 days. The start of the growing season occurs approximately 70 days earlier in the south than in the north, while the end of the growing season may take place up to 50 days later in the south than the north.

Analyses of snow cover over the territory varied depending on the dataset used. The indicators linked to the beginning, end and duration of snow cover suggest that the snow water equivalent has changed little between 1981 and 2010, while the duration of snow cover has decreased. This is linked primarily to an earlier end to the snow season and less to a later start.

The bioclimate analysis for the 1981−2010 period led to the identification of seven categories for the region north of the 55^th parallel (Figure 1). By contrast, only four categories figured in the original classification by Gerardin and McKenney (2001), which was based on observations from weather stations from 1966 to 1996. The new categorization allows the description of certain important topographic features with more precision. Moreover, the subpolar zone has expanded in the north, while the polar area is now smaller, and precipitation is greater throughout the territory compared to the original map.

Although we produced numerous indicator maps and reviewed the distribution of bioclimates for northern Quebec, users of this data should be cautioned against drawing certain conclusions given its associated uncertainty. Indeed, the differences between the reanalyses point to the fact that uncertainties remain important in northern Quebec. It is impossible to favour any one of the studied reanalyses over the other, largely because of the lack of observations that could serve to validate the data. The information presented here must therefore be used prudently.

• ArcticNet

• Centre d’Études nordiques

• Environnement Canada

• IREQ

• INRS-ETE

• Ministère du Développement durable,

• Environnement et Lutte contre les changements climatiques (MDDELCC)

• Canadian Forest Service