Oceanography has come recently unusual idea to weigh the ocean in a single point to determine its water weight.
Prof. Christopher Hughes, from the National Oceanography Centre, says that “pressure accurately measure variables in a single mass point will indicate World Ocean”. highest point in May according to pressure, says specialist, is the central tropical Pacific, where deep waters are more quiet as anywhere.
Instrument should be placed away from sources of variability, oceanic and terrestrial Professor Hughes believes that explains this need through an analogy: it’s like I watch it fill a bath and to see progress, you to look not at the end from the faucet, where the water is swirling and sprinkles, but at the opposite end, where the water level rise is slow and steady.
But what would be important to know how the ocean weigh?
We know that the world of ocean water increases by 3 mm per year, but we have to separate the different causes of this increase.
For example, you can warm ocean waters, leading to expansion - increase the volume without changing its mass. In contrast , if the ocean gets more water from the melting glaciers, ocean mass increase.
And because we do not know how much ice will melt, turning into water reaching the ocean, we need to implement a long-term monitoring system to measure these increases.
Making pressure measurements in the Pacific Ocean during the last decade, Christopher Hughes andteam were able to show that, each year, between March and September, in sea water enters a huge amount – 6 trillion tons, which would lead one ridge sea level by 1.7 cm.
Much of this water evaporates, leaving the ocean in the next six months – but not all.
Currently, it can be followed by measuring the annual cycle of water entering and leaving the ocean using either pressure measuring equipment or floating instruments and satellites. But none of these methods allows a really precise measurement of the quantity of water that accumulates in the ocean every year.
Prof. Hughes hopes that engineers will meet the challenge of building a more sensitive, able to measure fractions of a millimeter water column and at the same time to bear tremendous pressure of water at a depth of 4 km.
Is a very difficult, he admits, because changes in pressure are about 10 million times smaller than the base pressure and oceanic abyss is a very hostile environment mechanical components of any instrument.