基于Mann-Kendall法的中国海洋环境质量变化趋势分析

Trend analysis of marine environmental quality in China based on Mann-Kendall method

海洋环境质量是海洋资源可持续开发利用不可忽视的重要因素,对长时间序列数据的变化趋势分析可提高对海洋环境演变的认识。基于《中国海洋环境质量公报》(2001—2015年),采用Mann-Kendall法对中国管辖的近海海域不同水质等级海域面积、赤潮发现次数、赤潮发现面积以及河流入海污染物排放量时间序列数据进行变化趋势分析。结果表明:中国近海第二类海域(依据《海水水质标准》(GB 3097—1997)分类)面积呈下降趋势,劣四类海域面积呈上升趋势,近海海洋环境污染的形势依然严峻。近海海域赤潮发现次数和面积均呈下降趋势,尤其是东海,下降趋势明显。河流入海排放主要污染物中,COD与营养盐排放量均呈上升趋势,其中COD排放量上升趋势明显;石油类排放量呈明显下降趋势。沿海人口、海洋生产总值与劣四类海域面积均呈强正相关。沿海人口的增加、海洋生产总值的增长可能会对中国近海环境造成一定压力。

Marine environmental quality is an important factor that can not be neglected in the sustainable development and utilization of marine resources.The trend analysis based on long time series data can improve the understanding of the evolution of marine environment.Based on the data of“China marine environmental quality bulletin”from 2001 to 2015,Mann-Kendall method was used to analyze the temporal variation of sea area of different level,number and area of red tide observation findings and river pollutant discharge in China.Decrease tread were observed on sea area of water quality of the second class standard(according to“Sea water quality standard”(GB 3097-1997)),whereas sea area of water quality inferior to the fourth class standard showed significant rising trend.Coastal marine environmental pollution situation was still grim.The number and area of red tide in China were declining,especially in the East China Sea.About the main pollutants emission amount from river,COD was increased the most,and minor increase of nutrient was observed,whereas oil emissions showed a clear downward trend.Coastal population,marine GDP and sea area of water quality inferior to the fourth class standard had a strong positive correlation,implying the increase of coastal population and the growth of marine GDP caused some pressure to China coastal environment.