Jonkers Art R T, Sharkey Kieran J
Department of Mathematical Sciences, University of Liverpool, Liverpool, United Kingdom.
Institute for Geophysics, Westfälische Wilhelms Universität, Münster, Germany.
PLoS One. 2016 Nov 10;11(11):e0166247. doi: 10.1371/journal.pone.0166247. eCollection 2016.
River water temperature is a hydrological feature primarily controlled by topographical, meteorological, climatological, and anthropogenic factors. For Britain, the study of freshwater temperatures has focussed mainly on observations made in England and Wales; similar comprehensive data sets for Scotland are currently unavailable. Here we present a model for the whole of mainland Britain over three recent decades (1982-2011) that incorporates geographical extrapolation to Scotland. The model estimates daily mean freshwater temperature for every river segment and for any day in the studied period, based upon physico-geographical features, daily mean air and sea temperatures, and available freshwater temperature measurements. We also extrapolate the model temporally to predict future warming of Britain's rivers given current observed trends. Our results highlight the spatial and temporal diversity of British freshwater temperatures and warming rates. Over the studied period, Britain's rivers had a mean temperature of 9.84°C and experienced a mean warming of +0.22°C per decade, with lower rates for segments near lakes and in coastal regions. Model results indicate April as the fastest-warming month (+0.63°C per decade on average), and show that most rivers spend on average ever more days of the year at temperatures exceeding 10°C, a critical threshold for several fish pathogens. Our results also identify exceptional warming in parts of the Scottish Highlands (in April and September) and pervasive cooling episodes, in December throughout Britain and in July in the southwest of England (in Wales, Cornwall, Devon, and Dorset). This regional heterogeneity in rates of change has ramifications for current and future water quality, aquatic ecosystems, as well as for the spread of waterborne diseases.
河水温度是一种水文特征，主要受地形、气象、气候和人为因素控制。在英国，对淡水温度的研究主要集中在英格兰和威尔士的观测数据上；目前尚无苏格兰类似的综合数据集。在此，我们展示了一个涵盖近三十年（1982 - 2011年）整个大不列颠大陆的模型，该模型通过地理外推法将范围扩展至苏格兰。该模型基于自然地理特征、日平均气温和海温以及现有的淡水温度测量数据，估算研究期间每个河段及任意一天的日平均淡水温度。我们还对该模型进行时间外推，以根据当前观测趋势预测英国河流未来的变暖情况。我们的结果凸显了英国淡水温度和变暖速率的时空多样性。在研究期间，英国河流的平均温度为9.84°C，平均每十年升温0.22°C，湖泊附近和沿海地区的河段升温速率较低。模型结果表明，4月是升温最快的月份（平均每十年升温0.63°C），并且显示大多数河流一年中平均有越来越多的天数水温超过10°C，这是几种鱼类病原体的临界阈值。我们的结果还发现，苏格兰高地部分地区（4月和9月）出现异常变暖，以及在整个英国的12月和英格兰西南部（威尔士以及康沃尔、德文和多塞特）的7月出现普遍降温情况。这种变化速率的区域异质性对当前和未来的水质、水生生态系统以及水传播疾病的传播都有影响。
