Wet Carbon / Dry Carbon

Surface-atmosphere carbon exchange in subboreal uplands, lowlands, and water bodies

Ankur Desai Dept. of Atmospheric & Oceanic Sciences Center for Climatic Research, NIES UW-Madison SAGE Seminar 7 May 2008

INTRODUCTION

Let’s get fluxy

A Global Experiment • Marland et al., DOE/CDIAC 8000 7000 6000 5000 4000 3000 2000 1000 0 1750 1800 Total Solid 1850 1900 Gas Cement 1950 Liquid Gas Flare 2000

A Global Experiment • NOAA/ESRL/GMD/CCGG 390 380 370 360 350 340 330 1980 1985 1990 1995 2000 2005 2010

A Global Experiment 8000 7000 6000 5000 4000 3000 2000 1000 0 1980 1985 Tot al Solid 1990 4 3.5

3 2.5

2 1.5

1 0.5

0 1980 1985 1990 1995 Gas Cement 2000 2005 Liquid Gas Flare 2010 1995 2000 2005 2010

A Living Planet in a Global Experiment • Sarmiento and Gruber, 2002,

Physics Today

A Complicated Living Planet in a Global Experiment • Peylin et al., 2005,

GBC

An Uncertain Complicated Living Planet in a Global Experiment • Friedlingstein et al., 2005,

J. Clim

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So What Shall We Do?

• Let’s measure stuff!

• Use regional experiments to monitor, examine, and model land-atmosphere exchange of CO2 • Chequamegon-Ecosystem Atmosphere Study (ChEAS) initiated in mid 1990’s in Northern WI – Mix of upland forest, lowland wetlands, and lakes

ChEAS is Tasty

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And Our Towers Are Tall QuickTime™ and a decompressor are needed to see this picture.

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My Friend Eddy… • Tracers in boundary layer primarily transported by turbulence • Ensemble average turbulent equations of motion and tracer concentration provide information about the effect of random, chaotic turbulence on the evolution of mean tracer profiles with time • In a quasi-steady, homogenous surface layer, we can simplify this equation to infer the surface flux of a tracer

Eddy Flux

 Eddy Covariance Flux

F c

 

a

  

w



c

  0

h

 

c



t dz

  Turbulent flux Equipment: • 3D sonic anemometer • Open or closed path gas analyzer • 10Hz temporal resolution • Multiple level CO 2 profiler Storage

What We See

What We See

What We See

What We Don’t See • Fluxes in low turbulence • Constant “footprint” • Components of flux • Energy balance

What We All See • Fluxnet database is large, but spatial distribution is poor!

What It Means • Micrometeorological forcing (air/soil temperature, light, water) explains much of hourly and daily fluxes • Synoptic forcing is important for understanding subweekly variability • Fundamental rate reaction equations for photosynthesis, respiration, decomposition generally pan out • Larger time lags exist in seasonal forcing (snow melt, growing degree days, canopy / micromet interaction…) • Long term variation is driven by vegetation type and age since disturbance - not easily observed by single site EC • Interannual variation is complex… • So what have we seen in ChEAS? (Greatest Hits Version)

UPLANDS

Up, up and away

Interannual Variability Is Large QuickTime™ and a decompressor are needed to see this picture.

It Can Be Regionally Coherent… • Lots of variation, some coherence WLEF tall tower Lost Creek wetland Willow Creek hardwood Sylvania old-growth

…If We Think We Can Observe It QuickTime™ and a decompressor are needed to see this picture.

We Can Try To Model It

And Fail Miserably • Ricciuto et al. (2008) AgForMet

And Fail Everywhere

Why!?!?

Biomass and Stocking Matter • Courtesy of P. Bolstad, UMN 10 8 6 4 2 0 Upland broadleaved - SM, MH, QA, BW, RM Lowland - WC, TA, BS Red pine - RP SM RP BW SM QA MB SM SM/AE QA QA QA MH WB SM RP SM SM WP MP/MH BS QA QA AF WS QA QA QA RP mh SM JP QA/RM MH 0 50 100 150 200 Live Biomass (t ha -1 ) 250 300 350 3 2 1 0 -1 -2 -3 0 MH RM JP/QA MH AF AL QA AL WS ML WP RP QA QA MH QA BF MH WB/RM QA QA SM QA WC QA MB QA/BS QA/RM SM mh QA SM MB RP RP RP BW MP/MH WC WC BS TA/BS TA/BS 1 2 3 Ln(basal area) m 2 ha -1 4 5

Invasives Matter • Cook et al. (2008) Ecosystems QuickTime™ and a decompressor are needed to see this picture.

Site History Matters • Desai et al. (2008) Ag. For. Met.

• Desai et al. (2007) JGR-G

Site History Matters • Tang et al., 2008, Ag. For. Met.

700 600 500 400 300 200 100 0 1400 1300 1200 1100 1000 900 800 837 1043 809 742 628 Soil YA IA MH OHD OHL 1295 949 1089 1027 935 4530 225 132209 148 105 94 54 109 69 18 Woody debris Stem Leaf Ecosystem YA: young aspen, IA: intermediate aspen. MH: mature hardwood, OHD: old-growth hardwood, OHL: old-growth hemlock

Stand Age and Climate Interact • Desai et al., 2005, Ag For Met QuickTime™ and a decompressor are needed to see this picture.

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Stand Age and Climate Interact QuickTime™ and a decompressor are needed to see this picture.

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Upshot on Uplands • Upland hardwood forests in subboreal Wisconsin are not all the same – Vegetation structure affected by land management – Disturbance history is not uniform – Biomass and stocking variations exist – Interactions of these with climate impacts makes interannual and longer term variation in carbon cycling interesting… – Much of the story remains to be told – Meteorologists have to turn into Ecologists

LOWLANDS

Wetter or not, here I come

Wetlands Are Not All The Same • Courtesy of N. Saliendra, USFS

South Fork Bog

Wilson Flowage Fen

Lost Creek Shrub Fen

Lots of Little Lowlands • Courtesy of P. Bolstad, UMN Conifer Broadleaf Shrub Herbaceous

Wetlands Like Water, Maybe

Water Table Affects Decomposition

Water Table Affects Decomposition at Specific Thresholds Water table height (cm)

Water Table Influences Productivity • Cook et al. (accepted) JGR-G

Water Table Influences Productivity • Cook et al. (accepted) JGR-G

Wetland Water Cycle Affects ET

Wetland Water Cycle Affects WUE

Downlow on Lowlands • Topography, hydrology, and coastal boundaries define wetland locations – Spatial scales can be small, hard to remotely sense – Even harder to delineate types of wetlands • Water table, hydrology, management interactions in wetlands affect decomposition, productivity, community composition, transpiration, and plant water use efficiency – Poorly constrained in models – Management of water as important as climate var.

– Wetlands store a lot of carbon

WATER BODIES

Lakes, lakes, everywhere

Upland-Lowland-Lake System • Cardille et al. (2007) QuickTime™ and a decompressor are needed to see this picture.

Small Lakes Recycle Land Carbon • Cardille et al. (2007) QuickTime™ and a decompressor are needed to see this picture.

What Lakes?

Lake and Land • [CO 2 ] Air flowing over lake > [CO 2 ] over land QuickTime™ and a decompressor are needed to see this picture.

Big Lake, Small Flux?

• Courtesty of V. Bennington, UW

Big Lake, Big Flux!

• Atmos. flux is ~3 Tg yr -1 = 35-140 gC m -2 yr -1 Urban et al., 2005

(Not) The Last Word On Lakes • Small water bodies are not large in area but may be hot spots for carbon efflux especially in certain times of the year and over certain watersheds • Large water bodies may have smaller CO 2 exchange than land, but it adds up over a large area • Very little modeling to date on coupled systems

CONCLUSIONS

A big mess

Forest For Trees?

Regional Flux

What To Do • Ecological data assimilation • Coupled upland-lowland-lake modeling • Carbon/water interactions • Long term observation networks • Other biogeochemical cycles (CH 4 , N) • Advanced instrumentation for regional flux and boundary layer observation • Incorporating land and water use policy/decisions into hypotheses, observations, models

Thanks • Desai lab and friends: Ben Sulman, Jonathan Thom, Shelley Knuth, Bill Sacks, Scott Spak, Will Ahue • ChEAS collaborators, esp. Bruce Cook, Paul Bolstad, Ken Davis, D. Scott Mackay, Nic Saliendra, Sudeep Samanta • CyCLeS team: Galen McKinley, Noel Urban, Chin Wu, Nazan Atilla, Val Bennington • Funding: DOE NICCR, NSF, USDA, NSF/NCAR, NASA, NOAA • Come visit us: – AOSS 1549, [email protected], 265-9201 • More info: – http://flux.aos.wisc.edu

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