How do they measure mean sea level?  
How do they measure mean sea level?
What is mean sea level of India? Are the sea levels rising? What causes rise in sea level? Do ships cause the sea level to rise? Oceanography: How are oceans zoned? How big is specific ocean? How much water is there in the sea? What is sea? What causes the rise and fall in sea level? How much water is there in the sea and ocean? What is the sea? How is atmospheric pressure of water measured? Why temperature decrease when elevation increases from mean sea level? How arbitrary are the divisions between the oceans? How many meters above sea level is Vancouver? How does effect the local weather patterns? How do they measure the population of the world? How many meters above sea level is Tokyo? How does effect the local weather patterns? How would you measure the supposed scientific level of a country? Or are they all equal but different? How is rainfall measured? How can scientist measure temperatures from stars and planets? How can we calculate the radius of the earth? How do they measure gravity in other planets and stars? How do I estimate the fractional change in the volume of Earths oceans due to an average temperature change of 1°C? How can you measure the atmospheric composition? How do tides occur in the sea? What are the causes that raise the water? How are boundaries understood between various oceans? What are geological and coastal features? How are masses of celestial bodies measured? How do you measure radio waves? How do you measure rain?