Advective Flux of Energy and Carbon Dioxide over Complex Terrain
Abstract
A detailed understanding of the net ecosystem exchange (NEE) of carbon dioxide between the atmosphere and the terrestrial biosphere is required to refine predictions of future climate. One of the many tools used to study NEE over various biomes and terrain types is the eddy covariance (EC) method. While EC has proven to be tremendously useful in observing turbulent flux, it is not a panacea. Balancing the measured incoming and outgoing energy around eddy flux towers continues to be challenging, especially over complex terrain. If the energy flux equation is not closed, scientists must wonder if the carbon dioxide equation suffers similar errors. One probable cause for the energy flux imbalance is advective flux, which is not measured by EC.
Observations from a two-tower system on a forested hillside provide a defensible measure of vertical advective flux of both energy and carbon dioxide. Horizontal advective flux was also approximated, with increased uncertainty during near-neutral and stable atmospheric conditions. Including advective flux measurements in the overall energy flux balance of the project site was most effective during unstable conditions, with mixed results under other atmospheric scenarios. Vertical and horizontal fluxes often changed at differing rates and varying magnitudes. Similarly, carbon dioxide advection and energy advection were often observed to change signs at different times, and usually differed substantially in magnitude. The evidence indicates that advective fluxes of energy and carbon dioxide were caused by different mechanisms.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B33I2789K
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCESDE: 0428 Carbon cycling;
- BIOGEOSCIENCESDE: 0438 Diel;
- seasonal;
- and annual cycles;
- BIOGEOSCIENCES