渤海海水pH时空分布特征与趋势分析

基于2011?2017年海水pH和环境参数数据，应用格网统计和时空矩阵方法，研究各环境单元内pH和环境因子同比变化及相关性，并对影响不同季节、区域和水体层次的相关因子作差异性分析，结果显示:(1) 2011?2017年间，渤海区域pH的空间分布整体相对稳定，各环境单元表层pH平均值为7.95～8.38，底层pH平均值为7.89～8.35，平均值绝对变化为1～1.5个标准差；(2)各环境单元pH时间序列趋于同步变化，由于空间分布不同，局部单元间存在差异，研究认为冬季表层pH低值和盐度高值空间分布特征一致；(3)渤海区域pH与叶绿素a浓度呈现显著正相关，表层pH季节性特征明显，且与叶绿素a时空分布特征一致，生物因素对近岸表层水体pH的调节起重要作用；(4) 8月间渤海底层出现pH局部低值的区域，分析发现这与水体层化形成低氧区域相一致，同时发现底层pH与溶解氧呈显著正相关；(5)利用格网化数据处理技术和时空矩阵分析方法，进一步显化了pH和环境因子特征信息，对气候变化下长时间尺度的分析研究提供了很好的技术支撑。

Spatial and temporal characteristics and trend of pH in the Bohai Sea

Based on the data of pH and environmental parameters from 2011 to 2017, using the method of grid statistics and time-space matrix, contrastive analysis of pH in each environmental unit and the correlation of pH and environmental factors were studied. Furthermore, the differences of relevant factors affecting different seasons, regions and water levels were analyzed. The results showed that: (1) during from 2011 to 2017, the spatial distribution of pH was relatively stable in the Bohai Sea, the average value of surface pH in environmental units was from 7.95 to 8.38, the bottom was from 7.89 to 8.35, the absolute variation of average value was 1?1.5 standard deviations; (2) the time series of pH in each environmental unit tend to change synchronously, but there were differences among the units due to the different spatial distribution, the distribution characteristic of surface pH in winter was consistent with the saline; (3) there was a significant positive correlation between pH and chlorophyll a content in the Bohai Sea, and the surface pH varied seasonally, which was obviously consistent with distribution and variation characteristics of chlorophyll a, therefore, biological factor played an important role in regulating the pH of surface water; (4) the low value region of pH in Bohai Sea bottom in August was consistent with the formation of hypoxic zones by regional water stratification, and it was found that the bottom pH was positively correlated with dissolved oxygen; (5) the characteristic information of acidification indicators was further displayed by gridding processing technology and time-space matrix analysis method, which provided a good technical support for long-time scale analysis and research under climate change.