珠三角地区淡水池塘养殖水温的变化特征

Variation Characteristics of Water Temperature in Freshwater Pond Aquaculture in the Pearl River Delta Region

关键词:  水温变化  水温预测  淡水池塘养殖  气象因子  珠三角地区

Key words:  water temperature variation  water temperature prediction  freshwater pond aquaculture  meteorological factors  Pearl River Delta region

摘要:

水温是淡水池塘养殖最重要的环境生态因子之一。为揭示淡水池塘不同深度水温的时空变化特征，利用广东省农业气象试验站2022年9月—2024年4月气象要素和11层池塘水温观测资料，采用数理统计和相关分析等方法，对池塘水温的变化规律进行系统分析，遴选了不同天气状况和高影响天气下水温预测的关键气象因子，并分季节得出了鱼类的适宜生长天数。结果表明：（1）在月变化上，池塘各层水温与珠三角地区气温变化趋势基本一致，2—8月各层水温总体呈上升趋势，其中4月上升最显著，8月达到峰值；9—12月转为下降趋势，12月下降最显著，次年1月达谷值。（2）在季节变化上，同一日内气温与各层水温相关系数均达到0.90以上。不同水层水温各季节的最大升幅呈现秋季>冬季>夏季>春季的规律；最大降幅则表现为冬季>夏季>春季>秋季。其中冬季水温变幅最大，介于-4.0~2.3℃之间。（3）晴天条件下，春季、夏季和秋季水温呈“白天低于气温、夜间高于气温”特征，春季最为明显；冬季水温全天高于气温，且夜间水温与气温差最大。阴天条件下，水温与气温的温差较小，春季水温略低于气温、冬季略高于气温，夏季和秋季水温表现为白天低于气温、夜间高于气温。雨天条件下，春季、夏季和秋季水温均高于气温，水温变化幅度较小；降水集中时段水温与气温差明显增大。（4）台风天气下，水温变化与气温呈正相关、与气压呈负相关趋势；强冷空气过境期间，水温与气温呈正相关趋势、与气压呈负相关趋势，水温降温后恢复至前期水平需要10天以上；高温天气下，水温与当天、前一天、前三天日平均气温和气压具有显著相关性；低温寡照天气下，水温与气温变化趋势一致，湿冷型较干冷型低温寡照天气变化幅度更小。（5）珠三角地区鱼类全年可生长期达351天，最适生长期长短分布为夏季（56天）>秋季（42天）>春季（38天）>冬季（13天）。

Abstract:

Water temperature is one of the most important environmental and ecological factors in freshwater pond aquaculture. To reveal the spatiotemporal variation characteristics of water temperature at different depths in freshwater ponds, this study used meteorological data and 11-layer pond water temperature observation data from the Guangdong Agricultural Meteorological Experimental Station from September 2022 to April 2024. Methods such as mathematical statistics and correlation analysis were adopted to analyze the variation rules of pond water temperature. Key meteorological factors for water temperature prediction under different weather conditions and high-impact weather events were selected, and the number of days suitable for fish growth was obtained by season. The results showed that: (1) In terms of monthly variation, the water temperature of each layer in the pond was basically consistent with the temperature change in the Pearl River Delta region. From February to August, the water temperature of each layer generally showed an upward trend, with the most significant increase in April and the peak in August; it began to decrease from September to December, with the most significant decrease in December and the valley value in January. (2) In terms of seasonal variation, the correlation coefficients between air temperature and water temperature of each layer within the same day all exceeded 0.90. The maximum temperature rise of water temperature in different water layers in each season followed the order: autumn > winter > summer > spring; the maximum temperature drop followed the order: winter > summer > spring > autumn. Among them, the water temperature variation in winter was the largest, ranging from - 4.0 ℃ to 2.3 ℃. (3) On sunny days, water temperatures in spring, summer, and autumn were lower than air temperatures during the day but higher at night, a phenomenon most pronounced in spring; in winter, the water temperature was higher than the air temperature throughout the day, and the difference between the water temperature and the air temperature at night was the largest. On cloudy days, the temperature difference between water temperature and air temperature was small: the water temperature in spring was slightly lower than the air temperature, that in winter was slightly higher than the air temperature, and that in summer and autumn was lower than the air temperature during the day and higher than the air temperature at night. On rainy days, the water temperature in spring, summer and autumn was higher than the air temperature, and the variation range of water temperature was small; the temperature difference between water temperature and air temperature increased significantly during the concentrated precipitation period. (4) Under typhoon weather, water temperature correlated positively with air temperature and negatively with atmospheric pressure. During the passage of strong cold air masses, the water temperature showed a positive correlation with air temperature and a negative correlation with air pressure, and it took more than 10 days for the water temperature to return to the level before the temperature drop. During high-temperature weather, water temperature correlated significantly with the mean air temperature and pressure of the current day, previous day, and three days prior (correcting the original error regarding negative correlation). Under low-temperature and low-light weather, the water temperature had the samevariation trend as the air temperature, and the variation range of humid-cold low-temperature and low-lightweather was smaller than that of dry-cold low-temperature and low-light weather. (5) The annual suitablegrowth period of fish in the Pearl River Delta region reaches 351 days, and the distribution of the optimalgrowth period follows the order: summer (56 days) > autumn (42 days) > spring (38 days) > winter (13days).