Water from ground to sky - New approaches to observing and predicting field to basin scale Evapotranspiration (ET) over crops and plantations

Conference: ‘UW Extension & Wisconsin Potato & Vegetable Growers Association (WPVGA) Grower Conference 2018’

How reliable are fluxtowers? As long as sample area is homogenous and uptime is good, eddy covariance is the gold standard for field-regional ET

Flux towers have pros/cons:

PROS:

• Easy to deploy on a tripod in a field, on solar power
• No moving parts, and mostly off-the-shelf technology
• Nearly 500 long running sites worldwide
• “gold standard”. It is one of the only ways to directly measure ET at hourly time scale
• At the same time, we also measure the surface heat exchange, carbon dioxide flux (productivity), and climate.

CONS:

• It is relatively expensive (total around $40-50K to purchase)
• Requires significant expertise (technical personnel), and regular maintenance.
• EC measures only upwind of the tower and when the atmosphere is “turbulent”, requiring application of methods to fill in data gaps and quality control data