论文部分内容阅读
冰山是南极冰盖-冰架-海洋系统中活跃的组成部分,南大洋海底地形是影响冰山运动与搁浅的重要因素,但前人对此鲜有研究,本文结合南极Bedmap-2海底地形数据和杨百瀚大学冰山数据库所记录的冰山运动轨迹数据分析了海底地形对冰山运动和搁浅的影响.结果表明:(1)冰山搁浅事件与搁浅冰山轨迹点的数量分布主要与冰山水下厚度分布有关,在水深为200~300m海域内数量最高.自由运动冰山在南极陆坡锋区域(海洋水深500m左右)存在数量与速度的峰值;(2)海底地形对冰山运动的直接影响是冰山搁浅,在沿南极海岸线外围水深低于2000m的362×10~4km~2的海域里,从冰架前缘崩解的小型冰山可能搁浅区(水深小于400m)占28%即不易搁浅,这些搁浅区主要分布在东南极与南极半岛沿岸.从大冰架上崩解的大中型冰山(长轴大于18.5km)可能搁浅区(水深小于800m)占总面积的74%即较易搁浅;(3)在水深小于2000m的海域内冰山运动速度与海水深度之间具有正相关性(R=0.85,P<0.01)(即海水越深的地方冰山运动越快),而海冰的季节性变化对这种相关性的影响不大,说明海底地形起伏所引起的海水深度的变化会对冰山运动速度产生影响.
The iceberg is an active part of the Antarctic ice sheet - ice shelf - marine system. The submarine topography of the Southern Ocean is an important factor affecting the iceberg movement and stranding. However, few studies have been made on this. In this paper, based on the Antarctic Bedmap-2 seabed data and The results show that: (1) The number distribution of the iceberg stranded event and stranded iceberg track point is mainly related to the underwater ice thickness distribution, and the The maximum number and speed of free-moving icebergs in the area of Antarctic slope front (seawater depth about 500m) exist. (2) The direct influence of seafloor topography on iceberg movement is that the icebergs run aground. In the area along the Antarctic coastline In the area of 362 × 10 ~ 4km ~ 2 whose peripheral water depth is less than 2000m, the small beakers that can disintegrate from the front edge of the ice shelf may have less than 28% stranded area (water depth less than 400m), which is mainly distributed in the southeast pole And the coast of the Antarctic Peninsula. Large and medium-sized icebergs (long axes greater than 18.5km) that may disintegrate from large ice shelves may stranded more than 74% of the total stranded area (water depth less than 800m) There is a positive correlation between the ice speed and seawater depth in the depths of less than 2000m (R = 0.85, P <0.01) (ie, the iceberg movement is faster in deeper sea areas), and the seasonal changes of sea ice affect this The correlation has little effect, which indicates that the change of seawater depth caused by the seafloor topography will affect the iceberg movement speed.