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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
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.
• My inversion appears to capture the location of the maximum sink but can’t obtain the overall source/sink total for area
• Max sink less than 50% of max sink of inventory
• Strong efflux in SE
GgC/0.5°
Post
erio
rs
P
riors
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,
• Comparison of integration of passive flux tracer between inversions, as function of distance from tower.
• This is sensitivity of afternoon observations to “daytime” fluxes (GPP>0)
• This is sensitivity of afternoon observations to “daytime” fluxes (GPP>0)
• A bit stronger signal coming in for SiBRAMS and implying possibly a stronger far-field signal
Integrating up to time series at towers
General point is that my signal (blue) is somewhat stronger than Thomas’s signal (green) my far field effect (grey-blue), which is over 500 km from tower, comprises of a significant
portion of the overall signal.
No smoking gun, where to go?
• Investigate sensitivity of LPDM to biases in vertical velocity (long distance effects)
• Best results so far are with short backwards integration time (a couple days) and CarbonTracker inflow. However, there are likely non-trivial far field flux contributions to towers and we know CT has positive bias.
• Reinvestigating SiB / RAMS surf energy interface (and co2 exchange) and trying to make more consistent
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