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Civil engineers design buildings, roads, and utility pipelines in the Arctic to rest on firm frozen ground. But as permafrost thaws due to increased air temperature, the ground subsides and infrastructure fails. This paper assesses the current tools used for mapping Arctic geohazard for civil infrastructure planning in the warming Arctic. We formulate an integrated framework to inform science-based decisions and policymaking in response to the ongoing environmental changes. This study first conducts a systematic review of the Arctic geohazard mapping tools. Tools used for Arctic geohazard mapping fall into three categories: analytical or statistical equations for geohazard assessment, modeling approaches for predicting the extent of permafrost degradation, and remote and in-situ sensing for monitoring the natural and built environments and data collection. A description of these tools, along with their limitations and applicability, is provided. Co-production of knowledge is important in developing a robust geohazard assessment tool. Based on the scientific and gray literature, however, we find that the literature of the use of knowledge co-production in the development of evaluation tools outside of health care and public governance is highly sparse. Through the review of Arctic geohazard mapping tools, we provide an integrated framework for Arctic high spatial-resolution multi-geohazards evaluation for civil infrastructure planning. Indigenous knowledge and local observations are included in the proposed framework. [ABSTRACT FROM AUTHOR]

With the abundance of wind resources in cold climates, a significant share of the worldwide wind energy installed capacity is located in those areas. However, the advantages of cold climate operation comes with challenges associated with ice accretion. Throughout the years, alternative operational strategies have been developed to cope with these challenges. Although many strategies, such as blade heating, have been commercially available for a long time, few field studies have investigated their performance. Evaluating the performance of wind turbines in cold climates is a hard task due to the lack standards and the variability of external factors influencing turbine behaviour. In this paper, a methodology to assess the performance of wind turbines in cold climates is illustrated with a case study. This methodology aims to provide a better understanding of how ice accretion impacts wind turbine performance. This methodology was exemplified with a case study where the performance of a turbine equipped with a retrofit hot air ice protection system was analyzed over a 9-day icing event. It was found that the usage of the cold climate solution yielded an average energy gain of 159 MWh and an average potential recovery of 62%. • Proposition of a methodology for assessing the performance of cold climate solutions for wind turbines. • Description of the process of power curve modelling, selection of control turbines and interpretation of icing events. • Case study of a 9-day icing event where the performance of a turbine with an ice protection system is analyzed. [ABSTRACT FROM AUTHOR]

Changes in winter low flow (WLF) in cold-region rivers affect engineering design, water quality, and river ecosystem health. This paper aims to quantify to what extent WLF will change under climate warming and to propose a practical forecasting model for WLF predictions. The new concept of cumulative watershed temperature (CWT) is used as a convenient lumped surrogate for complicated hydrological processes that influence WLF. Statistical analyses of century-long flow data from the Fraser River in British Columbia, Canada show a strong dependence of WLF on CWT. In winter season, time series of CWT and WLF are shown to each divide into a falling and a rising limb at the data point of their lowest values, being −358 °C and 827 m3/s (historical averages), respectively. The falling and rising limbs describe the cumulative freezing and thawing effects of air temperatures fluctuating around the freezing point on WLF changes. The correlation between CWT and WLF (time series) data points on the rising limbs forms the forecasting model, expressing WLF as a function of CWT in terms of their z-scores. The model takes input of Global Circulation Model (GCM) projections of temperature increases by the end of 21st century under different Representative Concentration Pathways (RCPs), and predicts changes of Fraser River WLF from the historical average. RCP4.5 causes a 22.6% increase (ensemble average from six GCMs). RCP8.5 increases WLF by 20% (for some future years) to 44% (for others). The methods reported in this paper can be adapted to other cold regions. • Climate warming causes future winter low flow of the Fraser River in B.C. to increase. • Cumulative watershed air temperature controls the magnitude of winter low flow. • Design low flows from traditional methods need corrections due to climate warming. [ABSTRACT FROM AUTHOR]

Permafrost is very sensitive to climate factors, with warm permafrost particularly vulnerable to climate change. This paper aims to provide a detailed case study of climate trends of a high-latitude Alaskan site underlain by warm permafrost based on historical data and predictions from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The climate data, including air temperature, precipitation, wind speed, and their annual and seasonal trends from 1950 to 2099, are presented for Bethel, Alaska. The downscaled data are compared with the historical data in the overlap period. Both air and design freezing and thawing indices are calculated using various methods. In comparison, the downscaled model predictions align well with air temperature and wind speed records but not for precipitation, indicating the need for further downscaling at a finer resolution. The historical annual temperature records show a warming rate of 0.40 °C per decade, which is predicted to almost double to 0.78 °C per decade in the 21st century, leading to shorter winters and longer summers. The historical annual precipitation increased by a rate of 14.8 mm per decade from 1950 to 2020, and this trend is predicted to continue but at a slightly lower rate. The wind speed decreased consistently from 1984 to 2020 by 0.9 km/h per decade. However, the CMIP5 predicts that such a trend will diminish, with the mean annual wind speed remaining almost unchanged in this century. The air freezing index exhibits a consistent downtrend from 1950 to 2020, whereas the air thawing index remained flat until 1980 and rose afterward; the CMIP5 predicts that both trends will continue in the 21st century. The design air freezing and thawing indices are sensitive to the assessment periods for both methods. An assessment period shorter than 30 years, e.g., ten years, is recommended to find design indices. It is conservative to use the monthly mean air temperature method for evaluating the design air freezing index and apply the extreme event method for the design thawing index. • Compare downscaled model data at a finer resolution with other models in CMIP5. • Assess the design freezing and thawing indices by two methods with varying periods. • Recommend methods and periods for evaluating design freezing/thawing indices. • Discuss climate change effects on infrastructure, design strategies, future studies. [ABSTRACT FROM AUTHOR]