Exploring Nocturnal Canopy Advection in Complex Terrain Through Active Heating Fiber Optics: Unraveling Temperature Dynamics and Airflow Patterns
- 1National Taiwan University, School of Forestry and Resource Conservation, Taiwan
- 2Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan
- 3Experimental Forest, National Taiwan University, Nantou, Taiwan
- 4National Taiwan University, Department of Atmospheric Sciences
Nocturnal advection significantly influences the accurate estimation of net ecosystem exchange (NEE). This phenomenon is prevalent in Taiwan's subtropical montane forests, introducing a potential bias when relying solely on eddy covariance data for carbon budget calculations. From the preliminary analysis, the wind speed can be well estimated through the temperature difference between the heated and unheated fiber optical.The derived five-minute average wind speed exhibits a high coefficient of determination (R^2) of up to 0.94.
In the current study, a fiber observational setup consisting of a 40m vertical section and a 90m horizontal section has been implemented to investigate temperature dynamics and airflow in complex terrain. The wind speed profile can be well reflected from the preliminary data analysis. Insights gained through this approach contribute to a better understanding of the nocturnal canopy advection model, offering valuable corrections to NEE estimates.
How to cite: Li, Y. F., Ma, K. F., Lin, C. J., Lai, Y. J., Lin, P. H., and Nakai, T.: Exploring Nocturnal Canopy Advection in Complex Terrain Through Active Heating Fiber Optics: Unraveling Temperature Dynamics and Airflow Patterns, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10295, https://doi.org/10.5194/egusphere-egu24-10295, 2024.
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Can you explain how the inferred profile of windspeed and turbulence intensity leads to corrections to NEE estimates? Thanks, Peter
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From the wind speed and turbulence intensity profile, we can know the period during which advection occurs under the canopy (decouple). When there is a lack of turbulent mixing, the eddy covariance system on the canopy can only measure the flux above the canopy, so it will estimation of NEE produces errors. Understanding the period during which advection occurs can allow us to know which periods the data may be incorrect. In the future, we will try to use wind speed profiles and gas analyzers under the canopy to re-evaluate the gas flux through advection.
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