![]() ![]() So icebergs having different aspect ratios may melt at different rates. Researchers know that as an iceberg is carried by currents, melting rates differ among the front, rear, sides, and underside (called the base) as a result of temperature variations and differences in the fluid flow. (It’s a common misconception that icebergs extend deep underwater compared with their length at the surface in fact, buoyancy can cause them to roll to reduce their submerged volume.) Researchers classify icebergs by their aspect ratio-defined as the ratio of the longest horizontal dimension (“length”) to the submerged depth-a parameter that can vary from 1 to 1000. Icebergs come in an enormous range of shapes and sizes the depths they reach also varies, though they rarely extend below 600 m. Roughly 45% of the melting comes from icebergs that have broken away from an ice sheet, so understanding iceberg melting is important for climate models. Melting ice sheets-including those in Greenland and Antarctica-add fresh water (with low salinity) to the oceans, with important consequences for the global climate. ![]() The researchers expect that this new understanding can help climate scientists improve models used to predict how ice melting will affect Earth’s oceans and climate. They found that narrower icebergs that extend deeper underwater melt faster than wider ones that are less deeply submerged. ![]() Combining experiments on blocks of ice with computer simulations, researchers have now demonstrated that an iceberg’s shape can greatly affect its melting rate. Iceberg melting is an important component of global climate simulations, but current models ignore some features, including iceberg shapes. Experiments show that iceberg shape-tall and narrow versus short and wide-has a large effect on melting rate, which for some icebergs may be 50% faster than previously thought. Melting icebergs add fresh water to the oceans, with potential consequences for the planet’s climate. ![]()
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