COLLABORATIVE RESEARCH: Patterns, Dynamics, and Vulnerability of Arctic Polygonal Ecosystems: From Ice-Wedge Polygon to Pan-Arctic Landscapes

北极变暖正在重塑苔原景观，因为数千年前的地冰融化，导致地面沉降差异，改变了沙漠般降水地区的水和雪的分布。整个北极的实地测量记录了永久冻土的长期和逐渐变暖，最近的观测还包括冰楔的快速退化，以应对一个单一的和异常温暖的夏天。该项目的目标是了解负责泛北极冰楔多边形苔原景观的演变的复杂和相互关联的过程相结合的实地测量，从9个加拿大，俄罗斯和阿拉斯加的现场，数值模拟和非常高的空间分辨率的光学图像，最近已成为整个北极苔原域。详细的图像和先进的处理算法相结合，将允许泛北极冰楔多边形的范围和类型（低和高中心）的映射。这一范围和细节的地图尚未公布，但有必要将冰楔多边形尺度上发生的碳、水和能量过程与更大的北极陆地-海洋-大气系统联系起来。目前，永久冻土融化和随后的碳释放，充其量，在全球模型中描述通过逐渐增加的活动层厚度，而实地观察清楚地表明，由于快速差异地面沉降冰楔融化苔原生态系统的额外的戏剧性变化。一个低中心的多边形景观，经过几千年的缓慢冰楔生长过程演变而来，整个夏天都可以容纳一片浅池塘的海洋，在繁殖季节支持无数的候鸟。在短短两年的时间里，这一景象可能会发生巨大的变化，浅水区曾经是裸露的干土丘，而地表水区域可能会缩小到融化的冰楔上方较深的池塘的狭长珠子。一组复杂的子多边形对流域尺度的响应将决定景观的命运。这些机制，土壤-植被-水连续体的一部分，将通过一个数值地球物理模型，通过实地测量和重复图像的冰楔演变通知定义。新知识将支持研究界完善北极在全球气候系统中的作用。该项目的更广泛影响包括通过支持一名研究生、一名博士后和一名早期职业科学家来培训新一代北极研究人员。阿拉斯加州的费尔班克斯是几名调查人员的基地，为向K-12学生展示冰楔退化的结果提供了一个极好的机会。产品，如冰楔多边形类型的地图和植被，水和地形的预计改造，是在空间和时间尺度，是相关的管理人员。冰楔多边形类型和地冰估计的数字地图将在为期沿着机构提供给在阿拉斯加运作的州和联邦机构，同时提供冰楔多边形生态系统预测。这些信息可以为有关生境保护或依赖地表水的石油和天然气勘探活动的管理决策提供信息。还将为一名记者和一名摄影师的实地旅行提供支助。

The warming Arctic is reshaping the tundra landscape as ground-ice that is thousands of years old thaws, resulting in differential ground settlement that alters the distribution of water and snow in a region with desert-like precipitation. Field measurements across the Arctic have documented long-term and gradual warming of permafrost and recently the observations have also included rapid ice-wedge degradation in response to a single and unusually warm summer. The goal of this project is to understand the complex and interlinked processes responsible for the evolution of the pan-Arctic ice-wedge polygon tundra landscape by combining field measurements from nine Canadian, Russian, and Alaskan field sites, numerical modeling, and very high spatial resolution optical imagery that has recently become available for the entire Arctic tundra domain. A combination of detailed imagery and advanced processing algorithms will allow pan-Arctic mapping of ice-wedge polygon extent and types (low- and high-centered). A map of that extent and detail does not yet exisxt, but is necessary to link carbon, water, and energy processes occurring at the ice-wedge polygon scale to the larger Arctic land-ocean-atmosphere system. Currently, permafrost thaw and subsequent carbon release is, at best, described in global models via gradual increases in active layer thickness, while field observations clearly show additional dramatic changes to the tundra ecosystem due to rapid differential ground subsidence as ice-wedges melt. A low-centered polygon landscape, which evolved over several thousand years via the slow process of ice-wedge growth, can harbor a sea of shallow ponds throughout the summer that supports a myriad of migratory birds during the breeding season. In just two years, the scene could change dramatically with exposed dry mounds where the shallow water bodies once were, while the surface water area can shrink into narrow elongated beads of deeper ponds above the melted ice-wedges. A complicated set of sub-polygon to watershed scale responses will determine the fate of the landscape. These mechanisms, part of the soil-vegetation-water continuum, will be defined via a numerical biogeophysical model informed by field measurements and repeat imagery of ice-wedge evolution. The new knowledge will support the research community in refining the role of the Arctic in the global climate system. Broader impacts of this project include training of the new generation of Arctic researchers by supporting a graduate student, a post-doctoral fellow, and an early-career scientist. Fairbanks, Alaska, the base for several of the investigators, offers an excellent opportunity to show K-12 students the results of ice-wedge degradation. The products, such as the maps of ice-wedge polygon types and the projected transformation of the vegetation, water, and topography, are at spatial and temporal scales that are relevant to managers. Digital maps of ice-wedge polygon type and ground-ice estimates will be given to state and federal agencies operating in Alaska in a half-day workshop along with ice-wedge polygon ecosystem projections. The information could inform management decisions about habitat protection, or surface-water dependent oil and gas exploration activities. There will also be support for field travel for a journalist and a photographer.