Predictability of Open Water in the Chukchi/Beaufort Seas and Other Regions

这笔赠款支持评估和实施方法的努力，以预测北极沿海海域秋季冻结和春夏冰退缩的时间。该研究的动机是认识到北冰洋越来越容易进行资源勘探，海运，旅游和其他活动，增加了对冰况的可靠季节性预测的需求。该项目将侧重于满足利益攸关方需求的区域规模。所有北极沿岸海域和加拿大北极群岛的航道都将受到检查，但重点将放在楚科奇海和博福特海。这承认这些地区是资源勘探的焦点，船只通过白令海峡进入或离开北冰洋必须经过这些地区，并作为支持生存狩猎的季节性露脊鲸迁徙路线的一部分。所提出的方法的核心是春季/夏季海冰退缩到给定位置的日期（例如，大陆架断裂）可以用来预测秋季回到该位置（即封冻）的日期，从而预测无冰期。这反映了海冰反馈和海洋热量吸收过程，这一直是海冰系统的一部分。简单地说，较早的季节性海冰融化和退缩导致黑暗的开放水域较早暴露，容易吸收太阳辐射，这意味着夏季结束时海洋混合层中的热量更多，推迟了秋季冰的生长。这表现在观察，在楚科奇海的开放水域期间的上升趋势是由晚秋季返回冰比早春/夏撤退，有很强的关系，冰撤退和返回的去趋势的时间序列的两个变量。大气变化和海洋热量输送等因素被视为调节海洋热反馈和海洋热量吸收的表现形式;这些变量沿着季节性气候预测将作为额外的预测因素加以审查。将确定哪些#8232;扇区预测最熟练和最不熟练，这些差异的原因，以及是否#8232;变化的海冰状态（例如，改变冰层厚度）正在改变可预测性。在
此外，还将检查多种过程，包括冬季大气条件、海洋热输送、冰厚度和表面融化开始，作为后退日期的可预报性来源&。这项研究将利用卫星对海冰范围和密集度、表面融化开始、冰的运动、厚度和年龄、海洋热通量测量的观测，以及国家环境评估中心耦合气候预报系统第二版的输出，沿着海平面压力场、温度场和两次现代大气再分析的其他变量。北冰洋，特别是楚科奇海和博福特海，对我国具有越来越重要的战略意义。拟议的#8232;努力在区域范围内提供海冰状况的熟练季节性预测#8232;服务于通过满足不同利益攸关方的需求，包括海洋#8232;航运机构，采掘业和生计狩猎，改善科学与决策相结合的方法的目标。研究生和本科生的支持包括帮助教育下一代科学家，研究结果将被吸收到科罗拉多大学的北极气候课程。

This grant supports an effort to assess and implement approaches to predict the timing of autumn freeze-up and spring-summer ice retreat in the Arctic coastal seas. The study is motivated by recognition that the Arctic Ocean is becoming more accessible for resource exploration, marine shipping, tourism and other activities, increasing the need for reliable seasonal predictions of ice conditions. The project will focus on regional scales addressing stakeholder needs. All Arctic coastal
seas and the channels of the Canadian Arctic Archipelago will be examined, but emphasis will be placed on the Chukchi and Beaufort Seas. This recognizes these regions as foci for resource exploration, where ships entering or exiting the Arctic Ocean via Bering Strait must pass, and as part of the seasonal bowhead whale migration route supporting subsistence hunting. The core of the proposed approach is that the date of the spring/summer sea ice retreat to a given location (e.g., the continental shelf break) can be used to predict the date of the autumn advance back to that location (i.e. freeze-up), and hence the open water period. This reflects albedo feedback and ocean heat uptake processes that have always been part of the sea ice system. Briefly, earlier seasonal sea ice melt and retreat leads to earlier exposure of dark open water areas that readily absorb solar radiation, meaning more heat in the ocean mixed layer at summer's end, delaying autumn ice growth. This is manifested in observations that the upward trend in the open water period in the Chukchi Sea is driven more by later autumn return of ice than an earlier spring/summer retreat, and that there is a strong relationship between ice retreat and return in de-trended time series of the two variables. Factors such as atmospheric variability and ocean heat transport are viewed as modulating expressions of albedo feedback and ocean heat uptake; such variables, along with seasonal climate forecasts, will be examined as additional predictors. It will be determined in which
sectors predictions are most and least skillful, the reasons for these differences, and whether
the changing sea ice regime (e.g., changing ice thickness) is changing predictability. In
addition, multiple processes, including winter atmospheric conditions, ocean heat transport, ice thickness and surface melt onset, will be examined as sources of predictability on the
date of retreat. The study will utilize satellite observations of sea ice extent and concentration, surface melt onset, ice motion, thickness and age, ocean heat flux measurements, and output
from the NCEP coupled Climate Forecast System, Version 2, along with fields of sea level pressure, temperature and other variables from two modern atmospheric reanalyses. The Arctic Ocean, particularly the Chukchi and Beaufort seas, is of growing strategic importance
to our nation. The proposed
effort to provide skillful seasonal predictions of sea ice conditions at the regional scale
serves the goal of improving methods of connecting science with decision making through addressing diverse stakeholder needs, including marine
shipping agencies, extraction industries and subsistence hunting. Support is included for a graduate student and undergraduate students to help educate the next generation of scientists, and study results will be assimilated
into an Arctic climate course at the University of Colorado.