Z. Zhang1,2, F. Chen3, M.
Barlage3, L.E. Bortolotti1,4, J.
Famiglietti1,2, Z. Li2, X.
Ma1,2, Y. Li1,2*
1 School of Environment and Sustainablity, University
of Saskatchewan, SK, Canada
2 Global Institute for Water Security, University of
Saskatchewan, SK, Canada
3 Research Application Laboratory, National Center for
Atmospheric Research, Boulder, CO, USA
4 Institute for Wetland and Waterfowl Research, Ducks
Unlimited Canada, Stonewall, MB, Canada
Corresponding author: Dr. Yanping Li
(yanping.li@usask.ca)
Key Points:
- An updated parameterization for wetlands reasonably captures spatial
extent and seasonal variation in the Prairie Pothole Region.
- Implementing this wetland parameterization in Noah-MP LSM shows strong
impacts on surface energy and water budget.
- Wetlands’ effects on regional climate is strong and evident,
especially in cooling summer temperatures, greatly mitigating heat
stress from heatwaves.
Abstract
Wetlands are an important land type – they provide vital ecosystem
services such as regulating floods, storing carbon, and providing
wildlife habitat. The ability to simulate their spatial extent and
hydrological processes is important for valuing wetlands’ function. The
purpose of this study is to dynamically simulate wetlands’ hydrological
processes and their feedback to regional climate in the Prairie Pothole
Region (PPR) of North America, where a large number of wetlands exist.
In this study, we incorporated a wetland scheme into the Noah-MP Land
Surface Model with two major modifications: (1) modifying the sub-grid
saturation fraction for spatial wetland extent; (2) incorporating a
dynamic water storage to simulate hydrological processes. This scheme
was tested at a fen site in central Saskatchewan, Canada and applied
regionally in the PPR with 13-year climate forcing produced by a
high-resolution convection-permitting model. The differences between
wetland and no-wetland simulations are significant, with increasing
latent heat and evapotranspiration while decreasing sensible heat and
runoff. Finally, the dynamic wetland scheme was tested using the coupled
WRF model, showing an evident cooling effect of 1~3℃ in
summer where wetlands are abundant. In particular, the wetland
simulation shows reduction in the number of hot days for more than 10
days over the summer of 2006, when a long-lasting heatwave occurred.
This research has great implications for land surface/regional climate
modeling, as well as wetland conservation, for valuing wetlands in
providing a moisture source and mitigating extreme heatwaves, especially
under climate change.