1 00:00:00,000 --> 00:00:04,000 Narrator: Operation IceBridge, you may know it from the 2 00:00:04,000 --> 00:00:08,000 the beautiful photos that pop up in your feed. 3 00:00:08,000 --> 00:00:12,000 But did you know that IceBridge is the largest polar airborne survey of its kind? 4 00:00:12,000 --> 00:00:19,000 IceBridge was designed to study annual changes in thickness of sea ice, glaciers, and ice sheets. As well as bridge the 5 00:00:19,000 --> 00:00:23,000 gap between the ICESat and ICESat-2 polar observing satellites. 6 00:00:23,000 --> 00:00:27,000 Between 2009 and 2019, IceBridge flew over a thousand 7 00:00:27,000 --> 00:00:31,000 missions, gathering data that has redefined 8 00:00:31,000 --> 00:00:35,000 our understanding of the cryosphere. 9 00:00:35,000 --> 00:00:39,000 So, let’s take a look back at some of the mission milestones from over the years. 10 00:00:39,000 --> 00:00:43,000 One of the first steps to measure sea ice thickness is to get a handle on the amount of 11 00:00:43,000 --> 00:00:47,000 snow that accumulates on top of it. 12 00:00:47,000 --> 00:00:51,000 The IceBridge team pioneered the use of a snow radar instrument to gather the first 13 00:00:51,000 --> 00:00:55,000 widespread dataset of snow thickness on top of both Arctic and Antarctic sea ice. 14 00:00:55,000 --> 00:00:59,000 Closer to land, 15 00:00:59,000 --> 00:01:03,000 the point at which a glacier begins to float is called a grounding line, 16 00:01:03,000 --> 00:01:07,000 and it’s a very challenging place to measure ice thickness. 17 00:01:07,000 --> 00:01:11,000 Using two instruments, a radar sounder and a gravimeter, 18 00:01:11,000 --> 00:01:15,000 the IceBridge team was able to survey hundreds of these complex transition zones, 19 00:01:15,000 --> 00:01:19,000 enhancing scientists’ understanding of the rapid changes in glacier behavior. 20 00:01:19,000 --> 00:01:23,400 In 2011, NASA scientists discovered 21 00:01:23,400 --> 00:01:27,000 a 19-mile long crack across the Pine Island Glacier, 22 00:01:27,000 --> 00:01:31,000 one of the fastest retreating glaciers in Antarctica. 23 00:01:31,000 --> 00:01:35,000 The crack measured 260 feet wide and 195 feet deep 24 00:01:35,000 --> 00:01:39,000 when it was observed. 25 00:01:39,000 --> 00:01:43,000 Throughout the mission, IceBridge was able to map rifts in ice shelves prior to major 26 00:01:43,000 --> 00:01:47,000 calving events. And while these events are part of a natural cycle, 27 00:01:47,000 --> 00:01:51,000 IceBridge’s observations helped scientists better record the changes in calving 28 00:01:51,000 --> 00:01:55,000 frequency and model how they may be related to a thinning ice shelf. 29 00:01:55,000 --> 00:01:59,000 The motion of the Antarctic Ice Sheet, 30 00:01:59,000 --> 00:02:03,000 the largest ice sheet in the world, is heavily influenced by 31 00:02:03,000 --> 00:02:07,000 the topography of the bedrock underneath. 32 00:02:07,000 --> 00:02:11,000 In 2013, the British Antarctic Survey used over 25 million measurements 33 00:02:11,000 --> 00:02:15,000 collected by IceBridge and other projects 34 00:02:15,000 --> 00:02:19,000 to develop a 3D map of Antarctica’s bedrock topography. 35 00:02:19,000 --> 00:02:23,000 Called Bedmap-2, it provided unprecedented 36 00:02:23,000 --> 00:02:27,400 detail of how the continents bedrock shaped the flow of the ice sheet. 37 00:02:27,400 --> 00:02:31,000 Data collected by IceBridge enabled 38 00:02:31,000 --> 00:02:35,000 many discoveries in the Arctic as well. 39 00:02:35,000 --> 00:02:39,000 A team from the University of Bristol used IceBridge’s radar data, 40 00:02:39,000 --> 00:02:43,000 along with other datasets, to uncover a 400-mile long canyon buried 41 00:02:43,000 --> 00:02:47,000 under nearly two miles of ice. 42 00:02:47,000 --> 00:02:51,000 This hidden canyon is longer than any other known on earth, provides a critical clue to modeling how melting ice 43 00:02:51,000 --> 00:02:55,000 is funneled into the Arctic Ocean. 44 00:02:55,000 --> 00:02:59,000 Using ice-penetrating radar data collected by IceBridge, 45 00:02:59,000 --> 00:03:03,000 scientists were able to build the first-ever age map of the layers 46 00:03:03,000 --> 00:03:07,000 deep inside the Greenland Ice Sheet. 47 00:03:07,000 --> 00:03:11,000 For the first time, scientists could navigate the history of Greenland’s ice layers, 48 00:03:11,000 --> 00:03:15,000 extending previously collected ice cores to better understand 49 00:03:15,000 --> 00:03:19,000 the ice sheet’s history and help build models of its future. 50 00:03:19,000 --> 00:03:23,000 An international team of scientists 51 00:03:23,000 --> 00:03:27,000 used decades of NASA data to uncover a massive impact crater 52 00:03:27,000 --> 00:03:31,000 hiding beneath the Hiawatha Glacier in northwest Greenland. 53 00:03:31,000 --> 00:03:35,000 At roughly a thousand feet deep and more than 19 miles wide, 54 00:03:35,000 --> 00:03:39,400 it is potentially one of the youngest large impact craters on Earth. 55 00:03:39,400 --> 00:03:43,000 56 00:03:43,000 --> 00:03:47,000 Cockpit: "It’s going to happen..5..4..3 57 00:03:47,000 --> 00:03:47,400 ..2..Mark on the overpass 043435 Zulu" 58 00:03:47,400 --> 00:03:51,400 Narrator: Ice was bridged on April 8, 2019, 59 00:03:51,400 --> 00:03:55,000 60 00:03:55,000 --> 00:03:59,000 with the direct underflight of the ICESat-2 61 00:03:59,000 --> 00:04:03,000 satellite over Arctic sea ice. 62 00:04:03,000 --> 00:04:07,000 For the first time, both ICESat-2 and IceBridge would be taking the same 63 00:04:07,000 --> 00:04:11,000 elevation measurements of the same ice. 64 00:04:11,000 --> 00:04:15,000 These mirrored measurements were critical in validating the satellites instruments 65 00:04:15,000 --> 00:04:19,400 and continue the legacy of IceBridge after the mission was completed. 66 00:04:19,400 --> 00:04:23,000 67 00:04:23,000 --> 00:04:27,000 Over the course of its 11-year mission, IceBridge 68 00:04:27,000 --> 00:04:31,000 completed 1056 scientific flights and provided a wellspring of data 69 00:04:31,000 --> 00:04:35,000 that fueled the publication of more than 660 papers 70 00:04:35,000 --> 00:04:39,000 and counting. 71 00:04:39,000 --> 00:04:43,400 The mission provided new insight into the processes driving the changes in the cryosphere, 72 00:04:43,400 --> 00:04:57,707 helping scientists better understand what we can expect in the future.