I want to describe some data which are measured every one hour (Fig. 1).
They fluctuate during "one day" (i.e. 24h). They also fluctuate everyday (e.g. magnitude on 1/17,1/18 differs largely).
And I was wondering, (1) when I describe the fluctuation of "1/17 0:00 ~ 1/17 24:00", should I use "diurnal fluctuation" ? (2) when I describe the fluctuation of "1/17,1/18,1/19,1/20...", should I use "daily fluctuation" ?
I compared the meanings I found in a dictionary - "diurnal" means "1. belonging to or active during the day; 2. having a daily cycle or occurring every day; ". I think meaning 1 is ruled out. However, meaning 2 contains the word "daily", which brings confusion to me.