Data Assimilation Meetings at Reading

Date Meeting type Speakers
20 November 2013 Invited Speaker Sarah Kemp (University of Bristol)
Data Assimilation in terrestrial carbon cycle modelling (pdf)
More accurate estimates of the net exchange of CO2 between the terrestrial biosphere and the atmosphere are crucial in improving predictions of future atmospheric CO2 levels. These predictions are calculated from complex carbon cycle/biosphere models, which are based on a number of parameterisations with uncertain parameters. I apply a particle filter method to estimate the posterior probability density function (pdf) of 19 parameters of the Biosphere Energy Transfer and Hydrology (BETHY) scheme, by assimilating atmospheric CO2 observations. I will then go on to compare these results with the more established Carbon Cycle Data Assimilation System (CCDAS), which also assimilates CO2 observations but using a 4DVar approach. Parameter transformations are used in both assimilation systems to constrain parameters to physically reasonable values. Results show the particle filter minimises the cost function well but is not yet getting to the minimum of the adjoint based CCDAS.

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