Abstract:Water temperature is one of the basic physical parameters of rivers and lakes. Rising temperature can transform these ecosystems over a broad range of factors (water mixing, water quality, biological conditions, etc.). In the case of rivers, their thermal regimes also can be modified by local conditions (e.g., tree cover, adjoining water bodies, etc.). In this paper, we address the functioning of the river-lake system in northern Poland (Kocunia River-Lake Sławianowskie) in terms of the effect of the lake on t… Show more
“…5). These results to some extent correlate with those obtained for the course of river downstream from the lake by Nowak et al (2020). In our case the impact of the reservoir is larger as the result of its large volume and the discharge of water from the bottom layer.…”
Based on the results of regular monitoring and remote sensing data the patterns of water temperature and ice regime of the Dnipro River within Kyiv, as affected by global warming and a hydropower plant, were identified. The characteristic features of this stretch of the river are increasing water temperature, and the decreasing thickness and duration of ice cover. The largest water temperature increase is in summer, with a somewhat smaller increase in autumn. The increase of water temperature in spring is much less than the increase in air temperature. In summer, the gradient of water temperature increase is a little bit less than that of air temperature. In autumn, the gradient of water temperature increase is larger than the gradient of air temperature increase. From April to August the lowest water temperature is usually observed near the Kyivska hydropower plant (HPP), which is located upstream. During this period the water temperature downstream from HPP increases. The uneven daily operation of HPP causes the alternation of areas with different temperature along the Dnipro River. In the cold season the water temperature in the Dnipro River is usually higher than in other nearby urban water bodies. Freezing of the water area usually starts from the small and shallow lakes and ponds. The main branch of the Dnipro River freezes last. On the whole, the sequence of ice melting on the waterbodies is the reverse of the freezing process. The longest ice cover duration in spring is observed in the bays with small water exchange, mainly located at a large distance from Kyivska HPP.
“…5). These results to some extent correlate with those obtained for the course of river downstream from the lake by Nowak et al (2020). In our case the impact of the reservoir is larger as the result of its large volume and the discharge of water from the bottom layer.…”
Based on the results of regular monitoring and remote sensing data the patterns of water temperature and ice regime of the Dnipro River within Kyiv, as affected by global warming and a hydropower plant, were identified. The characteristic features of this stretch of the river are increasing water temperature, and the decreasing thickness and duration of ice cover. The largest water temperature increase is in summer, with a somewhat smaller increase in autumn. The increase of water temperature in spring is much less than the increase in air temperature. In summer, the gradient of water temperature increase is a little bit less than that of air temperature. In autumn, the gradient of water temperature increase is larger than the gradient of air temperature increase. From April to August the lowest water temperature is usually observed near the Kyivska hydropower plant (HPP), which is located upstream. During this period the water temperature downstream from HPP increases. The uneven daily operation of HPP causes the alternation of areas with different temperature along the Dnipro River. In the cold season the water temperature in the Dnipro River is usually higher than in other nearby urban water bodies. Freezing of the water area usually starts from the small and shallow lakes and ponds. The main branch of the Dnipro River freezes last. On the whole, the sequence of ice melting on the waterbodies is the reverse of the freezing process. The longest ice cover duration in spring is observed in the bays with small water exchange, mainly located at a large distance from Kyivska HPP.
PurposeThe IRONMAN® triathlon is an endurance multisport discipline of high popularity. Professional IRONMAN® triathletes need to qualify for the IRONMAN® World Championships and, therefore, would benefit from identifying the fastest race courses. Our purpose was to identify the fastest races held for professional IRONMAN® triathletes competing from 2002 to 2022.MethodsThis was an observational study, sampling 7,078 race records (380 different events in 55 different event locations) of professional IRONMAN® triathletes of both sexes (4,235 males and 2,843 females). We downloaded information about sex, nationality, both split (swimming, cycling, and running) and overall race times, the event location, and the year. Information about race course characteristics, water temperatures, and air temperatures was obtained. Descriptive statistics were calculated for each event location, and factorial ANOVA tests were used to explore the statistical significance of the results. A confidence interval of 95% was adopted.ResultsThe fastest overall IRONMAN® average race times were achieved during the IRONMAN® Tallinn, IRONMAN® Switzerland held in Thun, and IRONMAN® Des Moines. A lake for the swim split characterized the first five courses, while the bike split featured rolling or hilly terrain. For the run split, most of the courses were characterized as flat. For environmental characteristics, lower water and air temperatures also added time to the average finish time.ConclusionsUnderstanding the fastest race courses and their characteristics would assist professional IRONMAN® triathletes in selecting races that offer the optimal conditions for their competition. Fast IRONMAN® race courses typically feature a lakeside swim course, a rolling or hilly bike course, and a flat run course.
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