Sorry dont know the answer but i hope this helps .Natural boundaries are things like mountain ranges and rivers. Artificial boundaries are based on surveyor mappings and distance. PLZ PRESS THE THANK YOU BUTTON?:-)
For a typical tide of the period of the semidiurnal period for the solar active tides are about 24 and 12 hours as [er the equilibrium tidal theory and those of the semidiurnal lunar tides are about 12.4 hours period of the day.
The tidal ranges occur to form the two high to two low tides a day and semi-diurnal has two low tides each and every day.
