The 2000/01 Surge of Yanert Glacier, Alaska

阿拉斯加山脉中部有许多激流型冰川，其中大部分位于德纳里断裂带上。然而，实际发生的浪涌是罕见的，因为它的复发时间很长，约为50-100年，在该地区只有三个冰川被记录为反复浪涌。其中之一是雅纳特，众所周知，它最后一次激增是在1942年。这与阿拉斯加东南部的冰川非常不同，那里的冰川在不到20年的时间里经常重复出现。浪涌的确切原因和行为尚不清楚，因此，每当它出现时，利用机会收集更多数据是很重要的。不幸的是，激增的确切年份或时间很难预测，也不可能提前为充分的实地工作做好计划。亚纳特冰川位于阿拉斯加山脉中部，但人们对它知之甚少，只知道它是一个激流型冰川，1942年曾观察到一个激流。最近的激增始于1999/2000年的冬末，但大部分都没有被注意到。2001年4月，又重新启动，并发展为大高潮。由于没有观察到持续两年以上的激增，雅纳特的激增很可能在今年夏天停止，明年冬天也不会恢复。首席调查员将飞往亚纳特冰川的终点，安装两台延时摄像机。人们将观察目前距离冰川终点约5公里的涌浪锋。它将被用来测量浪涌锋面的前进速度，并确定前进停止的时间。第二台摄像机将被放置在冰川前面。预计潮水的结束将与一场大洪水同时发生。这台摄像机将记录下洪水何时发生。首席研究员还将使用手持GPS设备记录浪涌前沿的位置。在这个季节结束时，他们将用机载测高系统飞行冰川的轮廓，并取回延时相机。该剖面将用于估计由于浪涌而产生的冰的总质量运输。

ABSTRACT TrufferOPP-0126363There are a number of surge-type glaciers in the central Alaska Range and most of them overlying the Denali Fault . The actual occurrence of a surge, however, is rare because of the long recurrence time which is about 50-100 years and only three glaciers have been recorded to surge repeatedly in this region. One of these is the Yanert which is known to have last surged in 1942. This is very different from the glaciers in southeast Alaska where surges are often repeated in less than twenty years. The exact causes and the behavior of surges are not known, therefore, it is important to take advantage of opportunities for more data collection whenever it arises. Unfortunately, the exact year or time of a surge is very difficult to predict and it is impossible to plan for adequate field work in advance. The Yanert Glacier is located in the central Alaska Range, but little is known about it other than it is a surge-type glacier and a surge had been observed in 1942. The recent surge started in the late winter of 1999/2000, but most of it went unnoticed. In April 2001, it had restarted again and developed into a major surge . Because no surges have been observed to last more than two years, the Yanert surge is likely to stop this summer and not resume next winter. The Principal Investigators will fly to the terminus of Yanert Glacier and install two time lapse cameras. One will observe the surge front that is currently about five kilometers from the glacier terminus. It will be used to measure the rate of advance of the surge front and to establish the time when the advance stops. A second camera will be placed in front of the glacier. The end of the surge is expected to coincide with a big flood. This camera will record if and when the flood occurs. The Principal Investigators will also record the position of the surge front, using hand held GPS units. At the end of the season, they will fly a profile of the glacier with an airborne altimetry system and retrieve the time lapse cameras. The profile will be used to estimate the total mass transport of ice that occurred as a result of the surge.