Complex sentence: Results, published in 2009, of radar measurements of the north polar ice cap determined that the volume of water ice in the cap is 821,000 cubic kilometers (197,000 cubic miles), equal to 30% of the Earth's Greenland ice sheet.
Split into simpler sentences: Results, published in 2009, of radar measurements of the North Polar ice cap determined that the volume of water ice in the cap is 821,000 cubic kilometers (197,000 cubic miles). That's equal to 30% of the Earth's Greenland ice sheet.