Meltwater circulation and permeability of Arctic summer sea ice derived from hydrological field experiments
Meltwater circulation and permeability of Arctic summer sea ice derived from hydrological field experiments
复制标题
水文现场实验得出的北极夏季海冰融水循环和渗透性
作者：
J. Freitag;H. Eicken
摘要对1995年和1996年夏季西伯利亚和北极中部海冰的渗透性和融水流动进行了研究。采用了一种测井技术来测量现场渗透率，测得的渗透率范围在10−11到10−8 m2之间。在1995年(高于正常熔化速率)和1996年(低于正常熔化速率)之间，渗透率变化了大约2倍。此外，释放荧光示踪剂(荧光素、罗丹明)还可以得出流速和评估相关的驱动力。粗糙冰中的水力梯度和池塘冰中的风应力被发现特别重要，每天将融化的水驱赶几米远的距离。人们发现，仲夏到夏末的冰层具有足够的渗透性，可以将融化的水从表面完全转移到冰层内部。然而，结果表明，上层冰层较低的渗透率以及融化水的重新冻结，特别是在融化季节的早期，促进了地表融化池塘的发展。
Abstract Permeability and meltwater flow have been studied in sea ice in the Siberian and central Arctic during the summers of 1995 and 1996. A bail-test technique has been adapted to allow for measurements of in situ permeability, found to range between 10−11 and 10−8 m2. Permeability varied by about a factor of 2 between 1995 (above-normal melt rates) and 1996 (below-normal melt rates). Release of fluorescent tracers (fluorescein, rhodamine) furthermore allowed the derivation of flow velocities and assessment of the relevant driving forces. Hydraulic gradients in rough ice and wind stress in ponded ice were found to be particularly important, driving meltwater over distances of several meters per day. The mid- to late-summer ice was found to be permeable enough to completely divert meltwater from the surface into the ice interior. It is shown, however, that lower permeabilities of the upper ice layers as well as refreezing of meltwater, particularly during the early melt season, foster the development of surface melt ponds.