# What is the physical meaning of second moment of wind velocity?

I have been reading some documents about meteorological data and many of them mention the second moment of wind velocity. I guess it has to do with the way the wind is changing but in such case I would call it a gradient... Therefore, what is it's correct physical representation?

• Can you provide the context ? The second moment is present in statistics as well - en.wikipedia.org/wiki/Moment_(mathematics) – gansub Jun 25 '19 at 9:03
• So this paper - link.springer.com/article/10.1007%2FBF00119410 says it is the variance which is what I suspected in my first comment. That it is a statistical quantity. – gansub Jun 25 '19 at 9:08
• I understand it's the variance but does this mean how the wind is variating as well? – Federico Gentile Jun 25 '19 at 9:10
• Yes. Take a look at that paper's equation(2) – gansub Jun 25 '19 at 9:11
• ok thanks a lot :) I am still confused why they do not use something like the gradient though to represent how the wind is variating – Federico Gentile Jun 25 '19 at 9:16