Heat flux, water temperature and discharge from 15 northern Canadian rivers draining to Arctic Ocean and Hudson Bay

This study examined heat flux from 15 Canadian northern rivers that drain to the Arctic Ocean and the Hudson/ James Bay. Based on statistical analysis of available water temperature and discharge data, we determined patterns and characteristics of discharge, water temperature, and heat flux in relation to seasonal air temperature and precipitation. We found similar seasonal cycles of discharge and water temperature across the study region, i.e. most rivers experiencing maximum discharge in June/July and highest water temperatures in July/August. The mean flows during the open water season (May to Oct.) vary from west to east along the Arctic Coast (with higher yield from the Mackenzie and Peel rivers), while river flows are higher with warmer water temperatures in western and southern Hudson Bay. The summed heat flux for the studied rivers was about 10.0 x 10(12) MJ along the Arctic Coast and 2.0x10(12)MJ around the Hudson Bay. Among the 9 rivers flowing directly into the Arctic Ocean, the Mackenzie River with the highest flow and warmest water temperature delivered the highest heat flux, i.e. average 9.5 x 10(12) MJ over the open water season during 1960-2015. These observed patterns in discharge, water temperature and heat flux were generally consistent with CHANGE model simulations for most rivers in northern Canada. The outcomes of our study provide critical knowledge of river thermal condition and heat transport to the northern seas, which will be useful for large-scale climate and ocean model development and validation, and climate/hydrology change investigations in the broader northern regions.

Automated summary

This study examined seasonal variations of discharge, water temperature, and heat flux of 15 Canadian northern rivers, identifying similar patterns such as peak discharge in June/July and highest water temperatures in July/August. The study also found differences in river flows along the Arctic Coast from west to east, with higher flows in the west and warmer water temperatures in western and southern Hudson Bay. The results provide critical knowledge for climate and ocean model development and climate change investigations in northern regions.