Sea Ice Near Thule, Greenland (image) NASA/Goddard Space Flight Center Caption Sea ice near Thule, Greenland. Only about 10 percent of sea ice is above the ocean's surface, which makes measuring ice thickness challenging. More accurate thickness measurements could potentially improve future seasonal sea ice forecasts. Credit Credit: NASA / Nathan Kurtz Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.