In the standard FAO-56 Penman-Monteith method, the reference surface is defined as a hypothetical well-watered grass reference crop with an assumed fixed crop height of:
Options:
(A) $0.05\text{ m}$
(B) $0.12\text{ m}$
(C) $0.25\text{ m}$
(D) $0.50\text{ m}$
Answer Key:
B
Step-by-Step Solution & Explanation
The FAO-56 Penman-Monteith specification defines reference grass with an assumed height of $0.12\text{ m}$, a surface resistance of $70\text{ s/m}$, and an albedo (canopy reflection coefficient) of $0.23$.