The infinite flux tower project: Contribution of land surface energy-balance heterogeneity to mesoscale circulations and flux tower biases
Abstract
For decades, long-term eddy-covariance observations of surface-atmosphere exchange have led to to better understanding of ecosystem functioning, climate feedbacks, and the carbon cycle. However, long-standing biases in surface energy balance closure and location bias limit eddy-covariance data from accurately sampling the regional scale of land surface processes and corresponding atmospheric responses. As a result, these two challenges hamper our ability to better benchmark Earth system models with eddy-covariance data. Here, we present a systematic evaluation of this bias in both observations and in large eddy simulations. In the LES, we find that spatial heterogeneity in surface fluxes can generate long-wave eddies that contribute to a large fraction ( 40%) of energy imbalance. Further, we demonstrate that several advanced flux computation methods across time, space, and frequency domains allow us to correct this bias in flux towers. Applying these approaches to scaling algorithms also leads to improved representation of the domain mean flux and its spatial distribution with an efficient number of towers. Finally, we introduce the Chequamegon Heterogeneous Ecosystem Energy-balance Study Enabled by a High-density Extensive Array of Detectors (CHEESEHEAD19), an upcoming NSF field experiment designed to specifically address energy-balance and location bias challenges by deploying a large number ( 20) of flux towers and related surface and atmospheric sampling within a single model grid cell (10x10 km).
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B21D..02D
- 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