Satellites are already in use for so many purposes today — from weather forecasting to communications, GPS, and more. Since the late 1970s, satellites have also been used to monitor changes in the Arctic sea ice. Data suggests that sea ice is thinning over time due to climate change. Over the last forty years, the extent of Arctic ice cover has been declining at a rate of 13%per decade. However, existing ways of measurement do not provide a clear and continuous picture of the state of sea ice.
This September, scientists developed a new method that combines computer modeling and satellite data to predict ice thickness all year round. Over the years, scientists have proposed several methods to measure ice thickness. These include flying planes over the Arctic Ocean or collecting field measurements.
Neither of these methods provides a full picture of Arctic melt, making year-long data collection difficult. Continuous data across the entire region from satellites is a great way for scientists to understand how climate change is playing out in the Arctic.
These satellites use special radar or laser-based altimeter instruments. Sea ice thickness is then calculated as the difference between the height of the ice and the top of the water(ice level — sea level). This method works well during the winter months — September to May.
Unfortunately, satellite-based sea ice thickness measurements are inaccurate during the summer months: the time of the year with the greatest melting. This melting creates a pool of liquid water on the surface. As a result, the simple calculation (ice level — sea level) does not work as radar systems are unable to differentiate between ocean water and ice, thus rendering measurements inaccurate.
New research led by Jack Landy, a scientist, seeks to tackle this age-old issue. The team used machine learning and deep learning methods to distinguish between seawater and ice.
The researchers built a model of the radar system’s predicted data and cross-referenced these values to those collected by a satellite. This model allows the researchers to obtain accurate, year-round Arctic sea ice thickness data.
【小题1】Why are satellite-based sea ice thickness measurements not accurate?| A．The ice melts in summer months | B．The radar system doesn’t work in winter. |
| C．The liquid water turns ice in cold days | D．The ocean water comes onto the ice surface. |
| A．The changeable climate change | B．The incorrect ice measurements. |
| C．The constantly flowing ocean water. | D．The great amount of melting ice. |
| A．By using satellites to collect data. | B．By collecting field measurements |
| C．By flying planes over the Arctic Ocean. | D．By using machine learning and deep learning methods. |
| A．A new device to measure ocean water | B．A new stage for the application of satellites |
| C．A new way to monitor Arctic sea ice changes | D．A new finding about the rising sea level |
