Explanations

left top: value of characteristic number for a single event.
left bottom: mean value of the characteristic number within the period of data analysis.
right top: maximum value of the characteristic number within the period of data analysis.
right bottom: minimum value of the characteristic number within the period of data analysis.

Examples

maximum flood current velocity	maximum flood current velocity (maximum)
maximum flood current velocity of one specific tide	maximum value of maximum flood current velocity within the period of data analysis

maximum flood current velocity (mean)	maximum flood current velocity (minimum)
mean value of maximum flood current velocity within the period of data analysis	minimum value of maximum flood current velocity within the period of data analysis