The persistence product uses the daily maximum significant wave height (Hs) recorded each day
of the selected time span, and tabulates the occurrences of the number
of consecutive days the maximum Hs is less than a given height.

For example if the maximum daily Hs is the following:

Day

Max Hs (m)

1

1.3

2

2.5

3

1.8

4

3.1

then the tabulated occurrences looks like this:

Height (m)

Occurrences

1

0

2

1,1

3

3

4

4

I.e. reading this second table starting from the bottom row.

4m - All four days experienced wave heights less than 4m.

3m - There were 3 consecutive days with Hs less than 3m (days 1,2,3).

2m - There were 2 occurrences of 1 consecutive days with Hs less than 2m (days 1 and 3). Short-hand (well, not in this case) is written 2@1.

1m - There were 0 occurrences of days with Hs less than 1m.

Daily maximum Hs

The daily maximum Hs for the selected time span is also displayed in a table below the persistence table.