Assessing filtering of mountaintop CO2 mole fractions for application to inverse models of biosphere-atmosphere carbon exchange

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Publication Type pre-print
School or College College of Science
Department Biology
Creator Bowling, David R.
Other Author Brooks, B.-G. J.; Desai, A. R.; Stephens, B. B.; Burns, S. P.; Watt, A. S.; Heck, S. L.; Sweeney, C.
Title Assessing filtering of mountaintop CO2 mole fractions for application to inverse models of biosphere-atmosphere carbon exchange
Date 2012-01-01
Description There is a widely recognized need to improve our understanding of biosphere-atmosphere carbon exchanges in areas of complex terrain including the United States Mountain West. CO2 fluxes over mountainous terrain are often difficult to measure due to unusual and complicated influences associated with atmospheric transport. Consequently, deriving regional fluxes in mountain regions with carbon cycle inversion of atmospheric CO2 mole fraction is sensitive to filtering of observations to those that can be represented at the transport model resolution. Using five years of CO2 mole fraction observations from the Regional Atmospheric Continuous CO2 Network in the Rocky Mountains (Rocky RACCOON), five statistical filters are used to investigate a range of approaches for identifying regionally representative CO2 mole fractions. Test results from three filters indicate that subsets based on short-term variance and local CO2 gradients across tower inlet heights retain nine-tenths of the total observations and are able to define representative diel variability and seasonal cycles even for difficult-to-model sites where the influence of local fluxes is much larger than regional mole fraction variations. Test results from two other filters that consider measurements from previous and following days using spline fitting or sliding windows are overly selective. Case study examples showed that these windowing-filters rejected measurements representing synoptic changes in CO2, which suggests that they are not well suited to filtering continental CO2 measurements. We present a novel CO2 lapse rate filter that uses CO2 differences between levels in the model atmosphere to select subsets of site measurements that are representative on model scales. Our new filtering techniques provide guidance for novel approaches to assimilating mountain-top CO2 mole fractions in carbon cycle inverse models.
Type Text
Publisher European Geosciences Union
Volume 12
Issue 4
First Page 2099
Last Page 2115
Language eng
Bibliographic Citation Brooks, B.-G. J., Desai, A. R., Stephens, B. B., Bowling, D. R., Burns, S. P., Watt, A. S., Heck, S. L., & Sweeney, C. (2012). Assessing filtering of mountaintop CO2 mole fractions for application to inverse models of biosphere-atmosphere carbon exchange. Atmospheric Chemistry and Physics, 12(4), 2099-115.
Rights Management (c)European Geosciences Union
Format Medium application/pdf
Format Extent 1,404,014 bytes
Identifier uspace,18315
ARK ark:/87278/s6000m0z
Setname ir_uspace
ID 709266
Reference URL https://collections.lib.utah.edu/ark:/87278/s6000m0z