• 关键词：溶解氧  饱和溶解氧  时空变化  全球变暖

• 基金项目：国家重点研发计划项目（No.2017YFA0605003）；国家自然科学基金项目（No.51922010）

• 黄炜惠
• 中国环境科学研究院, 环境基准与风险评估国家重点实验室, 北京 100012

• 马春子
• 中国环境科学研究院, 环境基准与风险评估国家重点实验室, 北京 100012

• 李文攀
• 中国环境监测总站, 北京 100012

• 何卓识
• 中国环境科学研究院, 环境基准与风险评估国家重点实验室, 北京 100012

• 张含笑
• 中国环境科学研究院, 环境基准与风险评估国家重点实验室, 北京 100012

• 霍守亮
• 中国环境科学研究院, 环境基准与风险评估国家重点实验室, 北京 100012

• 摘要：溶解氧是衡量地表水环境质量的重要指标.为科学实施水污染防治和水生态系统修复，系统解析了我国近十五年不同区域溶解氧的时空变化特征，探讨了全球变暖对不同区域饱和溶解氧的影响.结果表明：①受海拔和温度影响，全国饱和溶解氧浓度存在显著的区域差异性，根据饱和溶解氧浓度将全国划分为3个区域，分别为北部高饱和溶解氧区、南部低饱和溶解氧区及中部饱和溶解氧过渡区；②2018年全国溶解氧浓度和饱和度达到I类水质的比例分别为72%和20.5%，冬季冰封期阻碍大气复氧的区域，不宜采用溶解氧饱和度对溶解氧进行评价；Mann-Kendall法分析表明，全国河流溶解氧浓度2010年下半年开始显著提高，人口密集、经济发达、工业化及水体盐度高和流速低是引起珠江及辽河入海口、长江下游溶解氧偏低的主要原因；③气候变化背景下，温度敏感的低温低海拔地区饱和溶解氧浓度下降最明显；到21世纪末，SSP5-8.5和SSP1-1.9情境下饱和溶解氧浓度将分别下降1.3 mg·L^-1和0.01 mg·L^-1，为适应全球变暖，需要加大污染物减排力度，保障水生态安全.

• Abstract：Dissolved oxygen (DO) is a primary index to estimate the environmental quality of surface water. The spatial-temporal variation characteristics of DO in various regions were analyzed in the past 15 years to scientifically prevent and control water pollution and restore aquatic ecosystem, and the impacts of global warming on saturated DO concentration in various regions were discussed. Results indicated that: ①Due to the impacts of altitude and temperature, there were significant regional differences in saturated DO concentration across the nation. Based on the saturated DO concentrations, the nation was divided into three regions: the high saturated DO region in South, the low saturated DO region in North, and the saturated DO transition region in Central. ②The proportions of DO concentration and saturation reached Class I Standard of Water quality in 2018 were 72% and 20.5%, respectively. It was not recommended for the estimation of DO using DO saturation in the regions with frozen period, which would hinder atmospheric reaeration. The Mann-Kendall analysis results indicated that the national DO concentrations in river had been significantly improved after the second half of 2010. Due to dense population, prosperous economy, and high industrialization, as well as high salinity and low velocity in water, the DO concentrations in the estuary of Pearl River and Liaohe River, and the Yangtze River downstream significantly decreased. ③As the climate change, saturated DO concentrations had been significantly reduced in the temperature sensitive region (namely, the region with low temperature and low elevation). By the end of 21^st century, the concentrations of saturated DO under the SSP5-8.5 and SSP1-1.9 scenarios would decline by 1.3 mg·L^-1 and 0.01 mg·L^-1, respectively. In order to adapt to global warming, it needs for more efforts to reduce pollutants and ensure water ecological security.

• Key words：dissolved oxygen  saturated dissolved oxygen  spatial-temporal variation  global warming

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