淡水鱼塘分层水温的变化特征

为了指导淡水养殖鱼塘水温的科学调控，保障水体生物安全越冬度夏，笔者选用武汉地区2011年3月至2012年2月淡水养殖鱼塘不同深度的水温数据及对应岸边的气温数据，应用数理统计分析方法分析其在不同时间尺度上的变化规律。结果表明：日尺度下不同深度水温日内的变化趋势与气温一致，气温的振幅较水温大，晴天气温及不同深度水温的振幅明显大于阴天。月尺度下3—7月气温及各层水温总体呈上升趋势，4月各层水温上升最显著；水温随深度增加而降低的趋势在晴天较多云天显著，阴天该趋势不明显。8月至次年2月，气温及各层水温呈下降趋势，1月下降最显著，水温随深度的变化呈降-升-降模式或降-升模式。季节尺度：水温随深度增加而降低的速率从大到小依次为春季、夏季、秋季，冬季水温随深度增加呈降-升-降模式。该结果可为武汉养殖池塘科学管理提供指导，也可为养殖鱼塘水温预报奠定基础。

Variation Characteristics of Water Temperatures at Different Depths of Fishpond

In order to ensure the creatures safely live through the winter and summer by scientific regulation of water temperature of fishing pond, different time scales characteristics of the vertical layered water temperatures were researched in according with the observing data of the vertical layered water temperatures of fishing pond and the shore air temperature from March 2011 to February 2012 at Wuhan. The results showed that, daily change of water temperature of fishing pond is the same as the shore air temperature while its amplitude was relatively small. Diurnal variation amplitude of air temperature and each layer water temperature under clear weather was significantly greater than under overcast. The monthly air temperature and each layer water temperature increased from March to July, especially in April, while decreased from August to the next February, especially in January, and followed a fall-rise-fall or fall-rise mode with increasing of depth. The water temperature decreased with increasing of depth is significantly obvious under clear weather than under overcast. On the season scale, the decreased rate of water temperature constantly decreased from spring to winter with depth increasing. During this period, the water temperature followed a fall-rise -fall mode with increasing of depth.