The spatial and environmental distribution of the global eddy covariance tower network.

Eddy covariance has revolutionized our understanding of ecosystem-atmosphere interactions. Multiple studies have characterized the climate space occupied by flux tower networks, but none to our knowledge have characterized if eddy covariance sites represent the global distribution of soil characteristics that are critical for determining ecosystem function or studied the distances between towers to apply ‘paired’ tower studies. Of 1233 global eddy covariance towers explored here, half had a nearest neighbor within 10 km. Soil database pixels with towers have nearly 20% more silt and 8% less sand than the global soil texture distribution, with more soil N (0.58 g/kg vs. 0.38 g/kg) and organic C (8.3 g/kg vs. 5.4 g/kg), and 10% greater cation exchange capacity in upper layers than pixels without towers. Global syntheses of eddy covariance towers should be cognizant that tower networks capture more fertile soils than the terrestrial surface on average. A logical way to improve global representativeness is to further build collaborations and invest in underrepresented regions.