Thawing of Permafrost Peatland and Thawing of Permafrost Peatland and Hydrological ImplicationsHydrological Implications
Masaki HayashiMasaki Hayashi11, Bill Quinton, Bill Quinton22, Alastair McClymont, Alastair McClymont11, , Larry BentleyLarry Bentley11, Brendan Christensen, Brendan Christensen11
11Geoscience, University of CalgaryGeoscience, University of Calgary22Geography & Env. Studies, Wilfrid Laurier UniversityGeography & Env. Studies, Wilfrid Laurier University
Prediction of Permafrost Thaw, 1990-2090
pink: complete thawing
Model Assumptions• Vertical energy transfer• Large (50 km) grids•No lateral flow of water and energy
Zhang et al. (2008. Geophys. Res. Lett., 35: L02502)
Reality (Scotty Creek)
1 km
lakepeat plateauisolated bogconnected bogchannel fen
Hay River Hay River LowlandLowland
Scotty CreekScotty Creek
0
200
400
600
1970 1980 1990 2000 2010
Ft. Simpson precip.
pre
cip
itat
ion
(m
m)
0
100
200
300
400
1970 1980 1990 2000 2010
BirchJean-MarieBlackstoneScotty
an
nu
al r
un
off
(m
m) Runoff = Total flow / Drainage area
Annual Total Basin Runoff near Ft. SimpsonFour Rivers (150-1,900 km2), Similar Landcovers
channel fenchannel fen
flat bogflat bog
peat plateaupeat plateau
permafrostpermafrost
Peat Plateaus Have Permafrost Cores
Water flows over frozen peat.
channel fenchannel fen
bogbog
-1.5
-1
-0.5
0
0.5
1
0 10 20 30 40
rela
tiv
e e
lev
ati
on
(m
)
distance from fen (m)
ground surf.
frost table
0.5 m0.9 m
Frost Table in Late August 2006GS: ground surface FT: frost table
zf
T = 0
T = Ts
frost table
ground srf.
Qm
Conduction dominates heat flux.
Qm = b (Ts – 0) / zf
b : bulk thermal conductivity
Hayashi et al. (2007, Hydrol. Proces. 21: 2610-2622)
0.1
0.2
0.3
0.4
0.5
0.4 0.5 0.6 0.7 0.8
Measuredde Vries Eqn.
(
W m
-1 K
-1)
water content
Differential Thawing by Conduction
Wet spots thaw faster.
2D Survey of Frost Table (FT)June 12, 2006
ground surf.
FT
• FT measured using FT probe on 0.25 m grids.
Wright et al. (2009, Water Resour. Res. 45: W05414)
• Subsurface flow simulation: 15 mm of rain added.Boussinesq equation is numerically solved.
Electrical Resistivity Imaging (ERI)
fenfen
bogbog
0 m 20 40 80fen plateau bog0 m
15
5
10
20
60
resistivity ( m)
102 103 104
FTclayclay
unfrozen peatunfrozen peatpermafrostpermafrost
0 m 20 40 80fen plateau bog0 m
15
5
10
20
60
resistivity ( m)
102 103 104
FT
ERI Line 1: Peat Plateau Transect
0
2
4
20 m 30 40 50 60
clayclayunfrozen peatunfrozen peat
permafrostpermafrost
depression
100m100m
ERI Line 2: Cross-Bog Transect
0 m 20 40 80fen isolated bog bog
0 m
15
5
10
20
60
resistivity ( m) 102 103 104
clayclayclayclay
sand lens
Conceptual Model of Permafrost Thaw
saturated, frozen peatsaturated, thawed peatunsaturated, thawed peat
new bog
1
2
3
preferential thaw
peat plateau
1. Thinning of canopy. Increase in radiation energy input.
2. Local thawing. Water-energy feedback causes further thawing.
3. Wet condition prevents trees from growing back. New bog forms.
19771977
Delineation of Peat Plateau on Aerial Images
200 m
Quinton et al. (2011, Hydrol. Proces., 25: 152)
20082008
Delineation of Peat Plateau on Aerial Images
Peat Plateau Area
1977: 53%
2008: 43%
200 m
Quinton et al. (2011, Hydrol. Proces., 25: 152)
Aug. 2002Aug. 2002
DataloggerDatalogger
Changes Evident on the Ground
July 2010
DataloggerDatalogger
200 m
Modelling Peat Plateau RunoffModelling Peat Plateau Runoff
Hydraulically equivalent plateau
Drainage of ground-water controlled by:- Radius- Gradient- Ksat distribution- Frost-table depth
Similar to MESH, but the moving FT is the challenge.
Coupled Permafrost-Hydrology Model for Circular Peat Plateau
Northern Ecosystem Soil Temperature (NEST) modelZhang et al. (2008)
vertical transfer
Simple Fill and Spill Hydrology (SFASH) modelWright et al. (2009)
lateral drainage
NEST-SFASH Preliminary Resultsfr
ost
tab
le (
m) 0
0.2
0.4
0.6
0.8simulatedobserved
J F M A M J J A S O N D J F M A M J J A S O N D2009 2010
0246
runoff
J F M A M J J A S O N D J F M A M J J A S O N D2009 2010
0
20
40 rainsnow melt
wat
er f
lux
(mm
/d)
L
LL
LL
L
L
L
L
Challenges and the Way Forward1. Storage and flow of runoff water in the fen-bog
network Basin-scale hydrological model.
2. Incorporate lateral thawing of permafrost in long-term model simulation (e.g. 50 years).
3. Ecology-hydrology feedback processes.
IP3 Legacy1. Scotty Creek research basin
2. Close collaboration with the local First Nation.
3. WLU-Northwest Territories Partnership for Research and Training (2010-2020, $10M project).
PeopleNicole Wright, Laura Chasmer, Chris Hopkinson, Tyler Veness, Rob Schincariol, and many others
FundingIP3 NetworkInternational Polar YearNatural Sciences and Engineering Research CouncilCanada Research Chair ProgramEnvironment Canada Science Horizons Program
Logistical Support Water Survey of CanadaEnvironment Canada (NWRI)Liidlii Kue First Nations
Acknowledgements