胶州湾气象水文要素的长期变化

LONG-TERM CHANGES IN MAJOR METEOROLOGICAL AND HYDROLOGICAL FACTORS IN THE JIAOZHOU BAY

摘要：

利用线性回归方法对胶州湾1898—2008年气温和降水、1962—2008年的水温和盐度四个气象水文要素的长期变化规律进行了分析。结果表明,百年来胶州湾地区气温的变化呈现波动上升趋势。从1920年前后到1950年的30年间,年平均气温的年变率为0.028℃,从20世纪60年代起至今,年平均气温的年变率为0.031℃。升温最显著的季节为冬季,夏季温度变化的幅度极小。胶州湾海水温度的变化趋势与气温一致。表层水温从1962年至2008年的年平均变率为0.023℃,年平均增量为气温的0.74倍。降水量的增加在1941—1975年间和1981年以后两个时期比较明显,年总降水量的年变率分别为9.44mm和10.95mm。胶州湾海水盐度从1981年以来呈现下降趋势,以夏季尤为显著,表层盐度年平均变率为-0.064,8月份盐度的年变率为-0.131。

Abstract：

Long-term variations of four meteorological and hydrological factors,including air temperature and precipitation（1898—2008）,sea water temperature and salinity（1962—2008） were analyzed using linear regression.Our results indicated that the air temperature in the Jiaozhou Bay area showed an overall increasing trend during the past 100 years.During 1920—1950,the rate of air temperature increase was 0.028℃/a,and it was 0.031℃/a from the 1960＇s to the present.The increase in temperature was most significant in winter and least in summer.In addition,we found that there was significant correlation between the annual mean temperature anomaly and the Pacific Decadal Oscillation（PDO） index.Furthermore,water temperature increase was consistent with the air temperature,especially in winter.For example,the increase rate from 1962 to 2008 was 0.023℃/a,74% of that in the air.In terms of precipitation,the increase was apparent from 1941 to 1975 and from 1981 and onward,and the rates of annual total precipitation increase were 9.44mm/a and 10.95mm/a,respectively.Accordingly,sea surface salinity showed a decreasing trend since 1981,especially in summer.The rate of salinity decrease was -0.064/a for the annual mean,and -0.131/a in August only.The decreasing trend of salinity in the Jiaozhou Bay was opposite to those in the adjacent seas,such as the Bohai Sea and some area of the Yellow Sea.