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