Apologies if this isn't the right place for this question. I guess it's somewhat research-related, but it seemed too basic to ask on mathoverflow.
I'm working through a paper (pdf) involving a technique to redistribute points along a contour. The details aren't really important, I don't think. All I'm trying to understand is what is meant by:
L is a length typical of the large-scale vorticity distribution
[Bottom of third page of the pdf, right after the centred equations]
Can someone explain what this means?