Andrew Schuh1, Thomas Lauvaux2, , Ken Davis2, Marek Uliasz1,

Dan Cooley1, Tristram West3, Liza Diaz2, Scott Richardson2, Natasha Miles2, F. Jay Breidt1, Arlyn

Andrews4, Kim Mueller5, Sharon Gourdji5, Kevin Gurney6, Erandi Lokupitiya1, Linda Heath7, James Smith7, Mathias

Goeckede, Scott Denning1 , and Stephen M. Ogle1

 

Contrasting atmospheric CO2 inversion results at a regional scale over the highly-inventoried area

of the Mid Continental Intensive.

1. Colorado State University, 2. The Pennsylvania State University, 3. Pacific Northwest National Laboratory, 4. NOAA Earth System Research Laboratory, 5. University of Michigan, 6. Arizona State University, 7. U.S. Forest Service

We gratefully acknowledge funding support from the National Aeronautics and Space Administration, Earth Sciences Division, to Colorado State University (agreement #NNX08AK08G).

Main Goal of MCI Synthesis• Compare and reconcile to the extent

possible CO2 fluxes from inventories and atmospheric inversions

C

CO2 CO2

CO2

CO2

CO2

CO2

C

Atmospheric Inversions

Inventories

“Top-down” vs “Bottom-up”

• Accurately captures all C contributions, whether known or unknown

• Integrates and mixes signals, thus generally better used at larger spatial scales then inventory

• Depends on accurate modeling of transport which can be difficult

InventoriesAtmospheric Inversions

• Process based and thus fluxes are “attributable”, good for policy decisions

• Generally tied to valuable commodities and thus tracked well, e.g. crop production, forest inventory, etc.

• Generally sampled at point locations and upscaled and thus possibly not as accurate at larger scales

Total 2007 NEE (Inventory minus fossil)

• Note largest sink driven by crop signal over corn belt• Largest uncertainty is over non-crop lands, presumably

forest driven, on scale of 50% of max sink strength• Note human respiration component over Chicago

MEAN SD

-450gCm-2yr-1

+350gCm-2yr-1 +250gCm-2yr-1

0gCm-2yr-1

PostersOgle H-184Ogle F-129West G-167

CarbonTracker as Baseline

Summing over MCI Region

CarbonTracker vs MCI Inventory

-350gCm-2yr-1

100gCm-2yr-1

CarbonTracker vs MCI Inventory

• In general, looks pretty reasonable -350gCm-2yr-1

100gCm-2yr-1

CarbonTracker vs MCI Inventory

MAX CROP SIGNAL

MAX CROP SIGNAL

• In general, looks pretty reasonable• However, max crop signal might be reversed?

-350gCm-2yr-1

100gCm-2yr-1

CarbonTracker vs MCI Inventory

MAX CROP SIGNAL

MAX CROP SIGNAL

• In general, looks pretty reasonable• However, max crop signal might be reversed?• CarbonTracker has little flexibility to adjust sub-ecoregion

scale fluxes, even if fine spatial scale data is available.

-350gCm-2yr-1

100gCm-2yr-1

Regional Inversions?• While some global inversions do reasonably well

(CarbonTracker), can we improve the estimates with regional higher resolution inversions?

• Three add’l inversions:– Penn State: with WRF, regionally at 10KM, w/ prior from

offline SiBCROP fluxes (w/ Uliasz LPDM particle model)– CSU: with RAMS, continentally at 40km, w/ prior from

“coupled” SiBCROP fluxes (w/ Uliasz LPDM particle model)– UMich: with WRF, at 40km, w/ geostatistical inversion

(and STILT particle model)

Anchoring Data• A ring of towers

instrumented by Penn State U. (Davis/Miles/Richardson)

• NOAA/ESRL tall towers

• Calibrated Ameriflux sites (Penn State)

SiB-CROP Prior NEE (TgC/deg2)(June 1 – Dec 31, 2007)

Posterior NEE (TgC/deg2)(June 1 – Dec 31, 2007)

Lauvaux et al. 2011 (in prep)

• Notice the max C drawdown in prior is somewhat similarly placed (NW Iowa/SW MN) to CarbonTracker (CASA).

• The posterior appears to ‘spread’ out the crop signal as well as relocate the max C drawdown location to central/northern Illinois.

• Spatially, results do depend upon network configurationLauvaux Poster H-182

SiB-CROP Prior NEE (TgC/deg2)(June 1 – Dec 31, 2007)

Posterior NEE (TgC/deg2)(June 1 – Dec 31, 2007)

Lauvaux et al. 2011 (in prep)

• Notice the max C drawdown in prior is somewhat similarly placed (NW Iowa/SW MN) to CarbonTracker (CASA).

• The posterior appears to ‘spread’ out the crop signal as well as relocate the max C drawdown location to central/northern Illinois.

• Spatially, results do depend upon network configurationLauvaux Poster H-182

Yields were better than expected

Yields were worse than expected

Inversion Priors/Posteriors (Jun – Dec, 2007)(GgC /0.5 deg 2 )

-625gCm-2yr-1

+400gCm-2yr-1

(source) Jun – DecJan – DecJan – Dec

Inversion Priors/Posteriors (Jun – Dec, 2007)(GgC /0.5 deg 2 )

-625gCm-2yr-1

+400gCm-2yr-1

(source) Jun – DecJan – DecJan – Dec

Shift in max C drawdown but much weaker sink than inventory or other inversions

Shift in max C drawdown but sink “appearing” closer to inventory

Inversion Priors/Posteriors (Jun – Dec, 2007)(GgC /0.5 deg 2 )

-625gCm-2yr-1

+400gCm-2yr-1

(source) Jun – DecJan – DecJan – Dec

Magnitude of sink looks reasonable and decently placed but no ability to move source/sink on finer scales

Time series of Inversion Results

2007

2008

Time series of Inversion Results

2007

2008Notice late drawdown captured by SiBCROP prior and somewhat by UMich inversion.

2008

Pos

terio

rs

Prio

rs

UMich 2008 CSU 2008

annual nee estimates for 2008 (GgC/gridcell)

Pos

terio

rs

Prio

rs

UMich 2008 CSU 2008

annual nee estimates for 2008 (GgC/gridcell)

Pos

terio

rs

Prio

rs

UMich 2008 CSU 2008

annual nee estimates for 2008 (GgC/gridcell)

• Has corn belt been re-located? … probably not• Something in CO2 records seem to point to anomalous fluxes to north of Iowa• LAI anomaly in MODIS?• Notes: inversions acting on long spatial scales, correction occurs OUTSIDE of Ring2, inventory more uncertain outside of corn belt,

How do we interpret overall?

• Inversions appear very similar, spatially, in 2007 between CSU and PSU and in 2008 between CSU and UMich

• However, we see significantly different magnitude of sources/sinks between CSU and the other two, with CSU having an estimated sink much weaker than the MCI inventory

• How do we investigate such problems?

Transport Uncertainty

• Summer time sensitivity (to surface) is stronger in CSU than PSU

• More similar in winter time

• Could this be why flux corrections are too weak in CSU’s inversion in summer?

PosterAndrews E-119

Transport Uncertainty• Stronger

sensitivity in LPDM-RAMS than STILT-WRF for top of LEF tower (afternoon obs)

PosterAndrews E-119

… however LPDM-SiBRAMS seems to match observations pretty well

Boundary impact• Impact of GV interpolated CO2 vs CT optimized CO2 appears to

range between 0.4 PgC and 1 PgC (stronger sink using CT as boundary) on background sink of 0.8 PgC to 1.5 PgC.

• Potential effect on MCI annual NEE estimate is smaller, estimated at 20-30 TgC on background of 120 TgC sink or more (Lauvaux) or slightly higher from UMich/CSU

2007

gC/m2 per year

gC/m2 per year

Summary on inversions as group• In general, NEE from two of the three inversions appear

to be in general vicinity of the inventory and the third (CSU) shows similar spatial traits to the others but needs investigation into absolute source/sink strength

• Mesoscale inversions show promise of increasing resolution of inversion results but still need work

• Continued work is needed to compare the transport fields which currently show significant differences (WRF-STILT, WRF-LPDM and RAMS-LPDM)

• Would like to continue investigation of differences between inventory and inversion results which have appeared for 2008.

BONUS MATERIAL