An Aircraft-Deployable GPS Stake Network for Antarctic Glaciers

这项工作的主要目标是设计和制造低成本的杆状GPS传感器，称为“标枪”，可以通过飞机空投的方式安装在冰川表面。这些位置将是本地压缩的数据，并由杆子上的低成本现场微控制器存储。然后，这些数据将通过铱星卫星数据网络以低成本的方式发送到英国南极调查局英国总部的现有数据存储库。作为该网络的实际实施，我们建议对南极冰盖变化最迅速的地区之一，南极洲西部的松岛冰川进行仪器测量，这些传感器网络为研究冰冻圈对海平面变化的当前贡献提供了关键数据集。科学界已经明确指出，有必要更好地监测冰川和冰盖对全球海平面变化的影响。目前海平面正以每年2.5至3毫米的速度变化，这比IPCC上一份报告（南极研究科学委员会，2007- 2008）的预测要高得多。越来越明显的是，冰盖和冰川对海平面变化的大部分贡献来自少数高度动态的地区，如偏远的松岛冰川。这些地区很难或不可能通过陆路跋涉或飞机降落到达。遥感可以提供这些地区的一些运动和流量数据，但这种技术受到时间分辨率差和缺乏稳定跟踪特征的限制。因此，可以通过空中部署的地面传感器设备是监测这些关键区域的唯一选择。我们的“标枪”将在合适的高度从飞机上扔下，迅速达到垂直的姿态，然后击中冰川表面，在那里它们将自己埋在合适的深度以提供稳定性。在这些设备最终被掩埋之前，将会收集多年来每天的位置更新。提案小组已经单独部署了类似的传感器，使用更传统的现场安装。由于移动飞机部署不良的风险增加，将部署更密集的标枪网络，增加我们的空间分辨率，预计一些传感器可能无法操作。消除飞机的重复起降是这种部署方法的另一个降低成本的好处。因此，这些装置也可以部署在任何区域，否则密集的传感器网络的安装将是不经济的，例如南极洲的深处。为环境敏感地区设计一种“一次性”传感器将需要由低环境影响的廉价材料制成的单个传感器。我们将重点关注标枪的空气动力学，以最大限度地提高成功的空中部署数量。最终的结果将是一个产品的设计和制造计划，该产品将用于英国南极调查局在接地线以外的几个冰川地区。它可以制造，并用于任何其他旨在从危险冰川地区收集数据的科学或工业努力。我们还将获得关于松岛冰川的重要知识；这些数据本身对IPCC和冰川学研究人员非常有用。英国南极调查局是仅有的几个有能力在南极洲西部开展后勤工作的国际组织之一，也是唯一一个有能力这样做的欧洲组织。首席研究员G. Hilmar Gudmundsson有多年在南极部署GPS设备的经验，并在世界各地许多冰川地区工作的丰富经验。这项建议的时间恰逢未来三年在松岛冰川上的其他计划工程，这有助于我们节省物流成本。

The main objective of the proposed work is to design and build low-cost pole-based GPS sensors, called 'Javelins', that can be installed on the surface of a glacier by airdropping them from an aircraft. The positions would be data compressed locally and stored by a low-cost field microcontroller on the pole. They would then be sent to an existing data repository in the British Antarctic Survey's UK headquarters, via the Iridium satellite data network in short cost-effective bursts. As a practical implementation of this network we propose to instrument one of the most rapidly changing regions of the Antarctic ice sheet, the Pine Island Glacier in West Antarctica, with a network of these sensors providing a key data set to study the current contribution of the cryosphere to sea level change. The scientific community has explicitly identified a need to better monitor the contribution of glaciers and ice sheets to worldwide sea level change. Currently sea-level is changing at a rate of 2.5 to 3 mm per year, which is considerably higher than projected in the last IPCC report (Scientific Committee on Antarctic Research, 2007-8). It has become increasingly evident that most of the contribution of ice sheets and glaciers to sea level change originates from a few highly dynamic areas, such as the remote Pine Island Glacier. Such regions are difficult or impossible to reach by ground via overland treks or through aircraft landing. Remote sensing can provide some motion and flow data in these areas, but such techniques are restricted by poor temporal resolution and lack of stable tracking features. Thus, terrestrial sensor equipment that can be deployed by air is the only option for monitoring these critical regions. Our 'Javelins' would be dropped from the aircraft at a suitable altitude, rapidly attain a vertical attitude, and strike the glacier surface where they would bury themselves to a suitable depth to provide stability. Multiple years of daily position updates would be collected from the devices before they would be eventually buried. The proposal team has already deployed similar sensors individually, using more traditional on-site installations. Due to the increased risk of poor deployment from a moving aircraft, a denser network of Javelins will be deployed, increasing our spatial resolution with an expectation that some of the sensors may be inoperable. Elimination of repeated aircraft landings and takeoffs are an additional cost reduction benefit of this deployment method. The devices could also therefore be deployed in any region where a dense sensor network installation would otherwise be uneconomic, such as the deep interior of Antarctica. Designing a 'disposable' sensor for an environmentally sensitive area will require individual sensors made of inexpensive material with low environmental impact. We will focus upon the aerodynamics of the Javelin, to maximize the number of successful airborne deployments. The end result will be a design and manufacturing plans for a product that will be of use to the British Antarctic Survey in several glacier regions beyond grounding lines. It may be manufactured and used in any other scientific or industrial endeavour that seeks to collect data from hazardous glacier areas. We will also gain critical knowledge of the Pine Island Glacier; this data itself will be of great use to the IPCC and the researchers in glaciology. The British Antarctic Survey is one of only a few worldwide organisations with logistics capable of operating in West Antarctica, and the only European organisation able to do so. The Principal Investigator, G. Hilmar Gudmundsson, has several years experience of deploying GPS devices in the Antarctic and extensive experience in working in many glaciated areas around the world. The timing of this proposal coincides with other planned works on the Pine Island Glacier in the next three years, helping us to save costs of logistics.