monthly mean carbon flux estimates: some network considerations lori bruhwiler, anna michalak,...
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Monthly Mean Carbon Flux Estimates:Some Network Considerations
Lori Bruhwiler, Anna Michalak, Wouter Peters, Pieter TansNOAA Climate Monitoring and Diagnostics Laboratory
Boulder, CO USA
David BakerNational Center for Atmospheric Research
Boulder, CO USA
2004 TransCom III Meeting
Fixed-Lag Kalman Smoother
• Balances Prior Flux Estimates Against New Information From Observations Using Prior Flux and “Measurement” Errors
2004 TransCom III Meeting
Fixed-Lag Kalman Smoother
• Balances Prior Flux Estimates Against New Information From Observations Using Prior Flux and “Measurement” Errors
Limits {
2004 TransCom III Meeting
Basis Functions
2004 TransCom III Meeting
Time-Stepping
Batch
2004 TransCom III Meeting
Time-Stepping
Batch
Smoother
2004 TransCom III Meeting
Propagation of Flux and Covariance Estimates
• Flux estimates incorporated by using basis functions to incorporate into background state
• Analytic technique used to propagate covariance forward in time
2004 TransCom III Meeting
Boreal North America
No Covariance
Propagation
Covariance
Propagation
2004 TransCom III Meeting
Advantages of the Fixed-Lag Kalman Smoother
• Basis Functions Transported For a Limited Period of Time (6-9 Months seems about right)
• Computationally Efficient For Multi-Decadal Inversions since the sizes of the matrices are much smaller
• Possible to do Many Inversions Quickly with Lots of Sites
2004 TransCom III Meeting
Comparison of Kalman Smoother and Batch Estimates
2004 TransCom III Meeting
Prior Uncertainties
Model-Data Mismatch Error
Select Sites
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What is the Model/Data Mismatch Error?
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2004 TransCom III Meeting
2004 TransCom III Meeting
Which Sites Should We Use?
Courtesy of T. Conway
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2004 TransCom III Meeting
2004 TransCom III Meeting
2004 TransCom III Meeting
2004 TransCom III Meeting
2004 TransCom III Meeting
2004 TransCom III Meeting
2004 TransCom III Meeting
Partitioning of Carbon Fluxes
2004 TransCom III Meeting
2004 TransCom III Meeting
2004 TransCom III Meeting
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2004 TransCom III Meeting
2004 TransCom III Meeting
2004 TransCom III Meeting
Summary
• Fixed-Lag Kalman Smoother Offers a Computationally-Efficient Method for Decadal Inversions
• Computational Cost of Keeping More Months of Transport Must be Balanced with Reductions in Uncertainty (Balance is Definitely Tipped Towards Fewer Months!)
• Changes in Network Configuration are Another Source of Uncertainty for Flux Estimates
• The NOAA Goal of +/- 0.3 GtC/yr for Temperate North America seems Achievable
2004 TransCom III Meeting
2004 TransCom III Meeting
Planned Cooperative Observing Network (2010)