Warning: Frozen Arctic Lakes Melt One Day Earlier Per Year

A new study from the University of Southampton revealed that Arctic lakes, which is usually frozen and covered with ice during winter months, is melting earlier each passing spring.

The study, published in the journal Scientific Reports, showed that the frozen Arctic lake is thawing an average of one day earlier per year between 2000 and 2013.

"Previous studies have looked into small numbers of lakes to show the impact of changes in temperature on the cyclic nature of lake-ice cover," said Jadu Dash, a professor at University of Southampton and lead author of the study, in a press release. "However, ours is the first to use time-series of satellite data to monitor thousands of lakes in this way across the Arctic. It contributes to the growing range of observations showing the influence that warmer temperatures are having on the Arctic."

For the study, the researchers monitored 13,300 lakes across five major study areas in the Arctic, including Alaska, Northeast Siberia, Central Siberia, Northeast Canada and Northern Europe, using satellite imagery. As NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) sensor circle around the globe on two satellites, it collects range of spectral and thermal data on daily basis. Using the MODIS data on how light is reflected off the lakes, the researchers were able to identify the freezing and thawing process.

The researchers discovered a strong link between decreasing ice cover and increasingly early temperature rise. The trends of early thawing in the spring were observed in five study areas. The researchers observed that the strongest trend of early ice break-up occurred in Central Siberia, with an average of 1.4 days earlier per year. On the other hand, Northern Europe showed the lowest change of ice break-up at 0.84 day earlier every year.

Ground-based observations suggest that the formation of ice cover on the Arctic lakes is starting later than before. With the earlier melt and later freezing, the total amount ice period could be reduced significantly. This could alter the balance between the land and the atmosphere.