Collaborative Research: Grounding Line Dynamics: Crary Ice Rise Revisited

最近的观测和模型结果表明，西南极阿蒙森海部分的坍塌可能已经在进行中。然而，崩塌的时间表以及正在进行的气候和海洋变化的影响是关键的悬而未决的问题。冰盖的完全解体将使全球海平面上升3米以上，这将产生重大的社会影响。为了更好地预测冰盖行为，需要更好地理解冰盖演化的控制因素。数值模式的结果表明，来自周围冰架和/或来自小范围接地冰升的支撑应该起到减缓冰从内部冰盖撤退和排放的作用。然而，用来开发和验证模型的现场观测很少。20世纪80年代初对罗斯海海湾的克拉里冰升进行的实地观测是一个明显的例外。该项目将用新的工具重新审视克拉里冰隆，以进行一系列测量，以解决冰升如何影响西南极罗斯海地区的冰排放的问题。该小组将包括一名研究生和本科生，并将参加一系列外展活动。包括雷达、地震和GPS仪器在内的新工具将被用于在克拉里冰隆及其接地线上进行有针对性的地球物理测量。该项目将使用这些新的测量数据，以及可用的辅助数据来提供接地线动态的数字模型。模型和测量将被用来解决(1)冰升是如何在过去几十年、冻结后的过去数千年以及冰川消融的时间尺度上演变的？(2)在雷达探测到的内部地层中保存了什么样的冰动力学历史？(3)冰升的存在/不存在对今天罗斯冰流的排放有什么动力学影响？(4)它如何有助于最近的惠兰冰流和美塞冰流的减缓？(5)在未来的环境变化下，冰升将有什么动力学反应？

Recent observations and model results suggest that collapse of the Amundsen Sea sector of West Antarctica may already be underway. However, the timeline of collapse and the effects of ongoing climatic and oceanographic changes are key unanswered questions. Complete disintegration of the ice sheet would raise global sea level by more than 3 m, which would have significant societal impacts. Improved understanding of the controls on ice-sheet evolution is needed to make better predictions of ice-sheet behavior. Results from numerical models show that buttressing from surrounding ice shelves and/or from small-scale grounded ice rises should act to slow the retreat and discharge of ice from the interior ice sheet. However, there are very few field observations with which to develop and validate models. Field observations conducted in the early 1980s on Crary Ice Rise in the Ross Sea Embayment are a notable exception. This project will revisit Crary Ice Rise with new tools to make a suite of measurements designed to address questions about how the ice rise affects ice discharge from the Ross Sea sector of West Antarctica. The team will include a graduate and undergraduate student, and will participate in a range of outreach activities.New tools including radar, seismic, and GPS instruments will be used to conduct targeted geophysical measurements both on Crary Ice Rise and across its grounding line. The project will use these new measurements, together with available ancillary data to inform a numerical model of grounding line dynamics. The model and measurements will be used to address the (1) How has the ice rise evolved over timescales ranging from: the past few decades; the past millennia after freeze-on; and through the deglaciation? (2) What history of ice dynamics is preserved in the radar-detected internal stratigraphy? (3) What dynamical effect does the presence/absence of the ice rise have on discharge of the Ross Ice Streams today? (4) How is it contributing to the slow-down of the proximal Whillans and Mercer ice streams? (5) What dynamical response will the ice rise have under future environmental change?