Key Points in Linking Dynamic Ecosystem Models with Permafrost and Hydrology Models A. David McGuire...
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Transcript of Key Points in Linking Dynamic Ecosystem Models with Permafrost and Hydrology Models A. David McGuire...
Key Points in Linking Dynamic Ecosystem Models with Permafrost and
Hydrology Models
A. David McGuire (UAF), Eugenie Euskirchen (UAF), and Shuhua Yi (UAF)
Arctic System Model Workshop, August 6 and 7, 2007
Interactions of Northern High Latitude Terrestrial Regions with
the Earth’s Climate System
Regional Climate Global Climate
Northern High Latitude Terrestrial Regions
ImpactsWater and
energyexchange
Exchange ofcarbon-based greenhouse
gases(CO2 and CH4)
Delivery of
freshwater to Arctic Ocean
From McGuire, Chapin, Walsh, and Wirth. 2006. Integrated regional changes in arctic climate feedbacks: Implications for the global climate system. Annual Review of Environment and Resources 31:61-91.
PhysiologyClimate warming
Structure
Land Use
composition, vegetation shifts
Disturbance
CO2, SH
Permafrostwarming, thawing
Physical feedbacks
Biotic controlMediatingprocesses
Snowcover
1, 2, 3, 4
5, 6, 7
8, 9
10, 11
12, 13
A
B
C
14
15
16
enzymes, stomates
fire, insects
logging, drainage,reindeer herding
D
E
I
II
IV
III V
fast (seconds to months)intermediate (months to years)slow (years to decades)
Response time
Mechanisms:: albedoGH: ground heat fluxSH: sensible heat fluxCO2, CH4: atmospheric concentration
Physiological feedbacks:(1) higher decomposition CO2(2) reduced transpiration SH (3) drought stress: CO2(4) PF melting: CH4(5) longer production period: CO2(6) NPP response to N min: CO2(7) NPP response to T: CO2
Structural feedbacks:(8) shrub expansion: (9) treeline advance: , CO2 (10) forest degradation but CO2, SH (11) light to dark taiga: but CO2, SH(12) more deciduous forest: , SH(13) fire / treeline retreat:
Physical feedbacks:(14) increased, then reduced heat
sink GH,SH(15) watershed drainage SH(16) earlier snowmelt
Terrestrial Research Focus Areas at IARC
• Physical Feedbacks Involving Permafrost Responses
• Feedbacks Involving Carbon and Water Responses
• Feedbacks Involving Snow Responses
• Feedbacks Involving Responses of Vegetation Composition and Structure
Friedlingstein et al. 2006; IPCC SRES 2000
Coupled Climate-Carbon Cycle Model Intercomparison (C4MIP)
20 - 220 ppm
Biospheric Carbon-Climate Feedback
- All soils treated as mineral soils - No C-hydrology dynamics in peatlands- No C-thawing dynamics in permafrost- No Nitrogen-Phosphorus limitations- Most models don’t have fire- Most don’t have vegetation dynamics
Up to +1.5°C
Atm
. CO
2 diff
eren
ce
(ppm
)
Feedbacks Involving Carbon and Water Cycle Responses
• Some Key Issues:- vulnerability to fire and permafrost thaw- delivery of carbon from high latitude terrestrial ecosystems to marine environments- dynamic simulation of wetlands
Vulnerability to CO2 and CH4 release
Zhuang et al. 2006. Geophysical Research Letters.
Permafrost thawing (MIT IGSM Scenarios)
Fire disturbance increase (~1% yr-1)
Soil ThermalModule(STM)
Hydrological Module(HM)
Terrestrial Ecosystem
Model(TEM)
MethaneConsumptionand Emission
Module
(MCEM)
Soil Temperature Profile Active Layer Depth
Water Table andSoil Moisture Profile
Labile carbon Vegetation Characteristics
40 35 20 10 0 –1
Source Sink
(g CH4 m-2 year-1)
Soil
Temperatures
at
Different
Depths
Upper Boundary Conditions
Heat Balance Surface
Snow Cover
Mosses
Frozen Ground
Thawed Ground
Frozen Ground
Lower Boundary Conditions
Heat Conduction
Heat Conduction
Heat Conduction
Moving phase plane
Moving phase plane
Lower Boundary
H(t)
Soil Thermal Model
H(t) Organic Soil
Mineral Soil
Output
Prescribed Temperature
Prescribed Temperature
Snow DepthMoss Depth
Organic Soil DepthMineral Soil Depth
Vegetation type;Snow pack; Soil moistureSoil temperature
Terrestrial Ecosystem Model (TEM) couples biogeochemistry and soil thermal dynamics
Snow
Thawing front
Moss
Peat
Mineral
Tem
perature update
Moisture update
Moss grow
th
Fire disturbance
0
1
2
3
4
5
6
1950s 1960s 1970s 1980s 1990s
Jun
e-Ju
ly-A
ug
ust
Tem
per
atu
re (
oC
)
FlatNorth slope
South slope
Decadal patterns of simulated soil temperature in top 10 cm ofof mineral soil in black spruce forests of interior Alaska forDifferent topographic positions (Yi, McGuire, and Kasischke).Field observations and modeling have shown that permafrost in black spruce stands on different topographicpositions have been warming since the mid-1960s, which means that over this time period, deeper duff layers in black spruce forests have become warmer and drier.
34 cm28 cm
25 cm
0 cm
12 cm
Control of depth to permafrost and soil temperature by the forest floor in Black spruce/Feathermoss Communities
C.T. Dyrness 1982
USDA, Forest Service, Pacific Northwest Forest and Range Experiment Station, Research Note: PNW-396
Site:
Washington Creek Fire Ecology Experimental Area, north of Fairbanks
Effects of Org Thickness onactive layer depth (S. Yi)
6 cm : moss
14 cm : peat
0 cm : moss
14 cm : peat
0 cm : moss
9 cm : peat
0 cm : moss
0 cm : peat
DFCC siteThawing front Freezing front
Kougarok burn site (k2)
• Biome: Tussock Tundra
• Lat: 65.25 oN
• Lon: 164.38 oW
• Elev: 110 m
• Aspect: south
• Slope: 3 o
• Fire History: 1971, 2002
K2 soil profiles
Before Fire• Upper organic layer
– Thick : 4 cm
– Porosity : 90
• Lower organic layer– Thick: 10 cm
– Porosity : 80
• Mineral– Sand :20, Silt: 58, Clay :22
After Fire• Upper organic layer
– Thick : 0 cm
– Porosity : 90
• Lower organic layer– Thick: 5 cm
– Porosity : 80
• Mineral– Sand :20, Silt: 58, Clay :22
Run from 1901 to 2006. The initial soil structure uses the one before fire. At July 2002, top two organic layers are removed, and only 5 cm organic layer is left. No other changes have been made at fire event.
Soil Temperature Simulation
fire
X-axis: doy
Y-axis: temperature (degc)
Soil Moisture Simulation --surface
X-axis: doy
Y-axis: soil wetness (%)
fire
Soil Moisture Simulation --shallow layer
X-axis: doy
Y-axis: soil wetness (%)
fire
Soil Moisture Simulation --deep layer
X-axis: doy
Y-axis: soil wetness (%)
fire
Implementation of fire disturbance
Thawing front
Moss
Peat
Mineral
SlopeAspect
Elevation
Soil temperatureMoisture
Active layer depth
Other issuesaffecting
burn depth
Burn depth
Implementation of moss growth and organic matter conversion
Vegetationbiomass
Moss biomass Moss thickness
live dead
fibric
mesic
humic
mineral
above below
Observations and model predictions at the Alaska-Canada scale, 1960-2005
(R2 = 0.82 (p<0.0001) for period 1960-2002)
1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Are
a B
urne
d (k
m2 )
0
10000
20000
30000
40000
50000
60000
Observations Predictions
Vegetation
Soil OrganicMatter
Soil Inorganic Carbon
CO2(g)
abvR
CO2(aq)
HCO3-
CO3-2
rootR
RH
CO2 (g)CO2 (g)
AlkalinityCO2(aq)
Shaded area = Modified TEM
soilR
DOC Stream Export
CO2 (g)
ChemicalWeathering
POC
GPP
erodePOCleachDOC
harvest
leachCO2 leachALK
evadeCO2
fire
Delivery of Carbon to Marine Environments
Region LeachDOC (Tg C yr-1)
Raymond et al.
(Tg C yr-1)
Ob’ 5.98 3.04
Yenisei 3.56 4.45
Lena 2.48 5.74
Mackenzie 4.07 1.40
Yukon 0.88 1.70
Arctic Rivers 27.61 25
Pan-Arctic Rivers 56.09 36*
Comparison of TEM Estimated DOC Leaching Rates during the 1990s to Measured DOC Export from Arctic Rivers
*includes rivers draining directly into the Arctic Ocean, the Arctic Archipeligo, Hudson Bay, and the Bering strait D. Kicklighter, J. Melillo, and A.D. McGuire
Depth to water table (DTW) (m) of 1990’s July
Dynamic simulation of wetlands in the Yukon
River Drainage Basin using a TOPMODEL approach
M. Stieglitz, D. Kicklighter, J. Melillo, and A.D. McGuire
Feedbacks Involving Snow Responses
• Retrospective Studies of Carbon and Energy Feedbacks
• Vulnerability of Climate System to Changes in Snow
-Examine patterns in snowmelt, snow return, and the duration of the snow free
season as they impact atmospheric heating
-Perform analyses for the 1910 –1940 and 1970 - 2000 time periods over the arctic-boreal land area above 50º N at a half-
degree latitude by longitude spatial resolutionE. Euskirchen and A.D. McGuire
<- 0.4 -0.4 - -0.3
-0.3 - -0.2
-0.2 - -0.05
-0.05 - 0.01
0.01 - 0.1
>0.1
Days per year shorter Days per year longer
Change in the duration of snow covered ground(anomaly):
Between 1970 -2000, the number of days of snow covered ground
decreased by an estimated 2.5 days per decade across the pan-Arctic.
1970 -2000
From Euskirchen et al. in press.
W m-2 decade-1Cooling
0.1 - -0.1
2 - 3 0.5 - 11 - 2 3 - 5 0.25 - 0.5 -1 - -0.25
-0.25 - -3
0.1- 0.25
Heating
Across the pan-Arctic, an overall reduction in the duration of snow covered ground by
~2.5 days per decade resulted in
atmospheric heating of ~1.0 W m-2 per decade.
Changes in atmospheric heating due to changes in the snow season, 1970-2000
1970 -2000
From Euskirchen et al. in press.
• Heating magnified in 1970-2000 period• Spring more important than autumn• Tundra important (high albedo contrast)
Feedbacks Involving Responses of Vegetation Composition and Structure
Energy budget feedbacks to regional summer climate
• Feedbacks from vegetation change– Tussock to shrub transition: 3.9 W/m2
– Tussock to forest transition: 5.0 W/m2
• 2% change in solar constant: 4.6 W/m2
– (glacial to interglacial change)
• Doubling atmospheric CO2: 4.4 W/m2
Chapin and McFadden
Soil thermal model coupled to TEM
DVM - TEM
MVP – TEM includes leaf, wood, and root components
Vegetation type;Snow pack; Soil moistureSoil temperature
VEGETATION
NETNMIN
Atmospheric Carbon Dioxide
GPP RA
NAVCS NS
SOIL
Lc LN NUPTAKEL,S
NLOST
NINPUT
RH
Cv
Nv1
Nvs
PFT1
Cv
Nv1
Nvs
PFT2
Cv
Nv1
Nvs
PFT3
Multiple vegetation
pools
Dynamic vegetation
model
Soil
Temps.
at
Different
Depths
Upper Boundary Conditions
Snow Cover
Moss & litter
Frozen Ground
Thawed Ground
Frozen Ground
Lower Boundary Conditions
Heat Conduction
Organic Soil
Mineral Soil
Prescribed Temperature
Prescribed Temperature
Snow Depth
Moss Depth
Organic Soil Depth
Mineral Soil Depth Moving
phase plane
Heat balance surface
Lower boundary
Heat Conduction
E. Euskirchen and A.D. McGuire
Warming of 12°C
(SRES A2 Scenario)Warming of 6°C
(SRES B2 Scenario)Warming of 2°C
(SRES B1 Scenario)
0
20
40
60
Mea
n (
± st
and
ard
dev
iati
on
) p
erce
nt
chan
ge
in p
lan
t n
et p
rim
ary
pro
du
ctiv
ity
bet
wee
n 2
002
- 21
00
Dynamic Vegetation Model coupled to the Terrestrial Ecosystem Model
Changes in plant productivity between 2003 – 2100 in northern Alaska: Large variation among the plant functional types in the shrub tundra,
represented with the error bars.
Boreal forest
Shrub tundra
Sedge tundra
E. Euskirchen and A.D. McGuire
1900 1950 2000 2050 2100
0e+0
02e
+05
4e+0
5
Year
Are
a B
urn
(km
^2)
Estimated Cumulative Area Burned for Interior Alaska
A2 HadleyB2 Hadley
CRU
A2 PCMB2 PCM
Are
a B
urne
d (k
m^2
)
Veg
Dis
tribu
tion
(1 k
m^2
)
1900 1950 2000 2050 2100
050
000
1500
00
a2hadcm3
010
000
3000
0
1950 20502000
deciduous
white spruce
black spruce
A2 Hadley (Most Area Burned) Single Replicate
Estimated Change in Summer Energy Budget
1900 1950 2000 2050 2100
102
104
106
108
Year
Wat
ts/m
2 A2 HadleyCRU
A2 PCMB2 PCM
B2 Hadley
Liu et al., 2005
Changes in surface albedo in response to fire
Grey line = Recent burnBlack line = Control
Coupling of DVM-TEM with CCSM3.0
• Coupling of DVM/TEM and frozen soil/permafrost module within CCSM
Mölders, Euskirchen, and McGuire