Impact of lakes on projected changes to the surface climate and hydrology

In this post I describe some results from our recent paper that looked at the impact of lakes on projected changes to the surface climate and hydrology for north-east Canada. It is well known that lakes influence the regional climate and hydrology, and therefore we had introduced a lake model in CRCM5 (Canadian Regional Climate Model) to improve the realism of simulations (Martynov et al 2012). Interactions between lakes and rivers are also now represented in CRCM5. We did some transient climate change simulations, with and without lakes (and therefore lake-river interactions), to assess the impact of lakes on projected changes to climate.

Due to the high thermal inertia of lakes, results suggest an attenuation of the projected increases in 2-m temperature for all seasons, especially for the northern part of the domain during winter, where the projected increases to 2-m temperature are the highest. The area-averaged attenuation of projected increases to 2-m air temperature by lakes ranges from 1°C in winter to 0.2°C during fall – the projected changes in the 2-m air temperature for winter and fall are 7°C (ranging from 3°C to 17°C over the region) and 6°C (ranging from 3°C to 7°C over the region), respectively, in the simulation with lakes.

The impact of lakes on projected changes to winter streamflow exhibits a north-south dipole pattern with augmentation of the projected increases in the northern and attenuation in the southern part of the study domain. The attenuation in projected changes to streamflows in the southern part is due to the attenuation in the projected changes to precipitation. The augmentation in projected increases in the northern regions is due to the additional water stored in lakes and released during winter.

For more information, please see: Huziy O and Sushama L, 2016: “Lake–river and lake–atmosphere interactions in a changing climate over Northeast Canada”, Climate Dynamics, doi:10.1007/s00382-016-3260-y

Impact of lakes on projected changes (for 2070–2100 with respect to 1980–2010) to 2-m air temperature (°C), total precipitation (mm/day), snow water equivalent (SWE, mm), latent heat flux (W/m2), streamflow (m3/s) for north-east Canada.

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