34 | Berichte des BSH Nr. 57 
23 
4. 
5 
6. 
(4 days from full moon or new moon) were considered and their mean value 
and uncertainty were calculated. Finally, the weighted mean was calculated 
‘or all annual values. The uncertainty ofthe MSpTD is 1 min. 
The mean neap tidal period (MNpTD) was determined from data of over 
100 German tide gauges over the period from 2007 to 2016. On an annual 
basis, all complete tidal cycles within the generalised neap tide period 
(4 days from half moon) were considered and their mean value and uncer- 
tainty were calculated. Finally, the weighted mean was calculated for all 
annual values. The uncertainty ofthe MNpTD is 1 min. 
The spring tide lag (in hours) is calculated from 7, as follows: 
T+[Trh]*29.53 h/Trh 
The neap tide lag (in hours) is calculated from 7», as follows: 
T„[Trh]*29.53 h/Trh - 6 h 
Ashift of 0.420666 Trh corresponds to half a mean lunar day (low water 
event with preceding transit number)