Question

Above which Richardson number does vertical mixing in winds disappear?

(a) 1

(b) 0.25

(c) 0.5

(d) 0.75

This question was posed to me in an online interview.

My enquiry is from Air Pollution topic in section Air Pollution of Environmental Engineering

Answer 1

Right option is (b) 0.25

Easy explanation: Beyond Richardson number of 0.25, the vertical mixing comes to a standstill and weak horizontal eddies alone remain.