Effect in atmosphere-ocean changes reflected by frequent large breakups of landfast ice and ice shelf in the Antarctic

利用卫星图像和船舶冰导航日志对南极固定冰的变化进行了研究，重点是Lutzow-Holmbukta（Lutzow-Holm湾）的破碎现象。虽然分裂事件的时空尺度对于每个事件都有所不同，但它们的开始通常在秋季，并且几乎总是在同一区域。具体而言，1997/98年的解体事件发生在广泛的地区，并在最初解体后持续了很长一段时间。从那时起，分裂一直重复到2004年，自1980年以来共发现了20次年度事件。此外，破冰船航行日志的信息显示，不稳定的快冰状况在20世纪80年代和90年代后期经常发生。通过对地面气象资料和近海浮冰分布的分析，发现异常浅的积雪深度和冰缘独特的后退模式是有利于快速冰破裂的因素。浮冰的分布控制着 ...更多信息 海湾内的海洋涌浪;在每年形成北部的保护性浮冰覆盖层之前，入侵的涌浪可能会在秋季机械地瓦解固定冰原。随着融化季节的推进，积雪减少也会导致快速冰的弱化，破碎的浮冰被盛行的南风吹向近海，这样，陆地快速冰的破碎和形成/持续的模式可能对出口冰川和内陆冰盖的动力学和热力学产生重要影响。为了促进这项研究，需要与卫星遥感相联系的实地测量，以检测冰川学对陆地坚冰稳定性的反应，其形式是不断变化的浮冰舌流动特性和内陆流域的海拔/厚度分布。具有高空间分辨率的卫星图像是非常有用的量化白濑冰川内流动的Lutzow-Holmbukta舌运动。少

Antarctic fast-ice variation has been investigated using satellite images and ship's ice navigation logs, focusing on breakup phenomena in Lutzow-Holmbukta (Lutzow-Holm Bay). Although spatio-temporal scales for breakup events vary somewhat for each event, their commencement is generally in autumn and almost always in the same region. Specifically, the 1997/98 breakup event occurred over a wide area and continued for a long time after the initial breakup. Since then, breakups have repeated until 2004, and a total of 20 annual events have been detected since 1980. Moreover, information from icebreaker navigation logs shows that unstable fast-ice conditions frequently occurred in the 1980s and after the late 1990s. From the analysis of surface meteorological data and the offshore pack-ice distribution, anomalously shallow snow-cover depths and a peculiar retreat pattern of the ice edge are found to be factors that favor fast-ice breakup. The pack ice distribution controls the propagation … More of ocean swell inside the bay ; encroaching swells are likely to mechanically disintegrate fast-ice field during autumn prior to the annual formation of the protective pack-ice cover to the north. Less snow cover also leads to fast-ice weakening as the melt season progresses and broken floes are then transported offshore by prevailing southerly winds.In this way, the patterns of landfast-ice breakup and formation/persistence likely exert an important influence on the dynamics and thermodynamics of outlet glaciers and also the inland ice sheet. To promote this study, field measurements linked with satellite remote sensing are required to detect glaciological responses to landfast-ice stability in the form of the changing flow characteristics of floating ice tongues and the elevation/thickness distributions of inland drainage basins. Satellite imagery with high spatial resolution is much useful for quantification of the tongue movement of the Shirase Glacier that flows inside Lutzow-Holmbukta. Less