A review of level ice and brash ice growth models

Brash ice forms in harbours and ship channels from frequent ship passages and the resulting freezing–breaking cycles create a unique ice formation. The brash ice accumulation over the winter season is a result of meteorological, thermodynamical and mechanical processes. A reliable brash ice growth model is an important asset when determining navigation routes through ice conditions and when establishing port ice management solutions. This review aims to describe the brash ice development and its modelling as well as the key parameters that influence the brash ice growth and its estimation. This paper summarises the brash ice growth models and the fundamental theories of level ice growth upon which these models are based, and outlines the main knowledge gaps. The results highlight the importance of porosity and piece size distribution and their effect on the consolidation process. The inclusion of the brash ice lateral movement and the side ridge formation would improve the accuracy of forecast models. Furthermore, the findings of the study identify the effect of omitting meteorological parameters such as snow and radiation, from the brash ice growth models. Their contribution to the level ice thickness suggests a significant influence on the brash ice consolidation process.

Ice microphysics of low-level ice clouds in the Arctic: Satellite analysis

<p>This study investigates low-level ice clouds in the Arctic and their potential relation to the surface aerosols. These aerosols or ice nucleating particles (INPs), are necessary for the heterogeneous nucleation of ice in temperatures above -38°C. Several studies in the past have investigated the sources of INPs and their nucleating behavior with response to the temperature. According to these studies, it has been suggested that a marine source of INPs coming from sea spray is able to nucleate ice in temperatures close to -5<sup>o</sup>C. What we do here is a large-scale comparison of boundary-layer ice clouds over open ocean and sea ice, over the whole Arctic region for the time period of 2006-2016. We use for this purpose a satellite-retrieved quantity, the ice crystal number concentration (N<sub>i</sub>), which we investigate in relation to the temperature. We study clouds with regard to the region and season they form and we examine their coupling to the surface. Our findings show - contrary to previous expectation - enhanced ice crystal numbers over sea ice compared to open ocean, in temperatures above -10<sup>o</sup>C. In lower temperatures this difference still persists for the lower Arctic latitudes (<70<sup>o</sup>N), especially for clouds that are coupled to the surface.</p>

Self-Regulation in High-Level Ice Hockey Players: An Application of the MuSt Theory

The purpose of the study was to examine the validity of core action elements and feeling states in ice hockey players in the prediction of performance. A second aim of the study was to explore the effectiveness of a 30-day program targeting action and emotion regulation. Participants were male ice hockey players drawn from two teams competing at the highest level of the junior Finnish ice hockey league. They were assigned to a self-regulation (n = 24) and a control (n = 19) group. The self-regulation program focused on the recreation of optimal execution of core action elements and functional feeling states. Separate repeated measures MANOVAs indicated significant differences in ratings of perceived control and execution accuracy ratings of self-selected visual and behavioral components of the action (critical for optimal performance) and psychobiosocial (feeling) states across recalled best and worst games. Results support the use of both action- and emotion-centered strategies for performance enhancement. Future research including psychophysiological markers is warranted.

Numerical Research on Global Ice Loads of Maneuvering Captive Motion in Level Ice

In level ice, the maneuvering motion of icebreakers has a major influence on the global ice loads of the hull. This study researched the influences of the drift angle and turning radius on the ice loads of the icebreaker Xue Long through a partial numerical method based on the linear superposition theory of ice loads. First, with reference to the Araon model tests performed by the Korea Research Institute of Ships and Ocean Engineering (KRISO), numerical simulations of Araon’s direct motion were carried out at different speeds, and the average deviation between numerical results and model test results was about 13.8%. Meanwhile, the icebreaking process and modes were analyzed and discussed, compared with a model test and a full-scale ship trial. Next, the maneuvering captive motions of oblique and constant radius were simulated to study the characteristics of ice loads under different drift angles and turning radii. Compared with the maneuvering motion model tests in the ice tank of Tianjin University and the Institute for Ocean Technology of the National Research Council of Canada (NRC/IOT), the numerical results had good agreement with the model test results in terms of the variation trend of ice loads and ice–hull interaction, and the influences of drift angle and turning radius on ice resistance and transverse force, which have a certain reference value for sailing performance research and the design of the hull form of icebreaker ships, are discussed.