Who first developed the Rossby number and how was it derived?

[meteo student]

Hoping to get an intuitive idea of the derivation behind the Rossby number that isused in fluid mechanics(atmospheric and oceanographic sciences). I know what it is and how it is used but I want to know Rossby hit upon the idea of the number that is named after him.

https://en.wikipedia.org/wiki/Rossby_number

 

[CapnGranite]

http://birner.atmos.colostate.edu/courses/rossby.pdf
Carl-Gustaf Arvid Rossby
The pdf has a couple figures showing how he first saw his waves and a portion of an early paper where he and MIT collaborators set down the concept.