1971—2020年天津市二十四节气气候变化特征

Analysis of the Climate Change Characteristics of the Twenty-Four Solar Terms in Tianjin from 1971 to 2020

  • 摘要: 利用天津市13个国家级气象站1971—2020年逐日气象要素资料,采用线性相关分析、t检验等方法,对天津市二十四节气气象要素变化特征进行分析。结果表明:1)二十四节气气温变化呈一定的不对称特征。大暑节气气温最高,小寒气温最低;清明至小满昼夜温差最大(11.6℃),秋分至霜降次之(10.5℃);春分至清明气温升幅最大(4.4℃),霜降至立冬气温降幅最大(4.8℃);所有节气平均气温都呈上升趋势,且春季型节气(立春至谷雨)升温最显著。2)降水量高度集中在夏季,夏至至立秋4个节气占全年降水总量的57.4%;降水量年代际变化存在明显差异,超半数节气降水量距平在20世纪70—80年代和21世纪第二个10年为正,而在20世纪90年代和21世纪第一个10年为负。3)春季风速最大,清明为最;所有节气风速均呈减小趋势,且达到极显著水平(P<0.01),春季减小幅度最大。4)日照时数小满最长,冬至最短;除春分外其他节气日照时数都呈减少趋势,夏、秋季减少趋势明显。5)相对湿度清明最小、大暑最大,且所有节气均呈下降趋势。6)气压的节气变化和气温相反,变化趋势不显著。

     

    Abstract: Based on the daily meteorological data during 1971-2020 from 13 national meteorological stations in Tianjin, this study analyzed the variation characteristics of meteorological elements for 24 solar terms by using linear correlation analysis and t-test methods. The results show that: 1) The temperature changes during the 24 solar terms exhibited a certain asymmetry. The highest temperature occurred during Greater Heat, and the lowest during Lesser Cold. The largest diurnal temperature range was from Pure Brightness to Lesser Fullness of Grain (11.6℃), followed by the period from Autumn Equinox to Frost's Descent (10.5℃). The greatest temperature increase was from Spring Equinox to Pure Brightness (4.4℃), and the greatest temperature decrease was from Frost's Descent to Beginning of Winter (4.8℃). The average temperature of all solar terms showed an upward trend, and the most pronounced warming occurred during the spring-type solar terms (Beginning of Spring to Grain Rain). 2) Precipitation was highly concentrated in the summer, with the four solar terms from Summer Solstice to Beginning of Autumn accounting for 57.4% of the annual precipitation. There were significant differences in the interdecadal changes of precipitation. More than half of the solar terms had positive precipitation anomalies in the 1970s-1980s and the 2010s, while negative anomalies were identified in the 1990s and the 2000s. 3) Spring witnessed the highest wind speed, with the highest value at Pure Brightness. The wind speed in all solar terms showed a decreasing trend, reaching an extremely significant level (P < 0.01), with the largest decrease in spring. 4) The longest sunshine duration was at Lesser Fullness of Grain, and the shortest at Winter Solstice. Except for Spring Equinox, the sunshine duration in other solar terms showed a decreasing trend, with a more notable decrease in summer and autumn. 5) The relative humidity reached the lowest at Pure Brightness and the highest at Greater Heat, and all solar terms exhibited a decreasing trend of relative humidity. 6) The solar term variation of air pressure was opposite to that of temperature, with no significant trend of variation.

     

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