An instrument that measures sea level using signals from satellite navigation systems, such as GPS, has been developed by scientists, Press Trust of India reported.
By using existing coastal Global Positioning System (GPS) stations, sea level and its variation can easily be monitored, researchers at Chalmers University of Technology in Sweden found.
Measuring sea level is an increasingly important part of climate research, and a rising mean sea level is one of the most tangible consequences of climate change.
According to PTI, Johan Lofgren and Rudiger Haas, scientists at Chalmers Department of Earth and Space Sciences, have developed and tested an instrument that measures the sea level using radio signals from satellite navigation systems: a GNSS tide gauge (GNSS stands for Global Navigation Satellite System).
"We measure the sea level using the same radio signals that mobile phones and cars use in their satellite navigation systems," said Lofgren.
"As the satellites pass over the sky, the instrument 'sees' their signals - both those that come direct and those that are reflected off the sea surface," Lofgren said.
Signals both directly from the satellites and signals reflected off the sea surface are measured by two antennas, covered by small white radomes.
"By analyzing these signals together, the sea level and its variation can be measured, up to 20 times per second," PTI reported. "The sea level time series is rich in physical phenomena such as tides (caused mostly by the gravitational pull of the Moon and the Sun), meteorological signals (high and low pressure), and signals from climate change. Through advanced signal processing, these signals can be studied further."
"Now we can measure the sea level both relative to the coast and relative to the center of the Earth, which means we can clearly tell the difference between changes in the water level and changes in the land," said Lofgren.
