| 摘要: |
| 通过2014年和2019年观测资料分析了渤海夏季底层水体氧亏损空间分布的年际差异，同时首次揭示了黄河口东侧莱州湾口区域的氧亏损现象，并利用三维物理生态耦合模式ROMS-CoSiNE探究了氧亏损分布年际差异的影响因素。2014年秦皇岛外氧亏损区（以溶解氧（dissolved oxygen，DO）饱和度小于70%为统计范围）主要向东扩展，而2019年则向东南向扩展；2014年黄河口外氧亏损区主要位于浅滩西南侧的深水洼地，而2019年则从浅滩西侧洼地延伸至黄河口外及莱州湾口区域。通过估算跃层存在期间底层水体的氧收支，得到垂向扩散和生物耗氧分别是底层DO浓度变化的主要源和汇。2014年和2019年秦皇岛外氧亏损空间分布的年际差异，与垂向扩散的差异有关，垂向扩散较弱的区域DO降低速率及降低量较大，氧亏损较强。2019年莱州湾口区域氧亏损与垂向扩散及跃层持续时间有关，较强的黄河径流与南风，有利于冲淡水的扩散，使得莱州湾口区域的跃层强度较大，垂向扩散较弱，DO降低速率较大，跃层持续时间较长，氧亏损强于2014年。此外，2014年秦皇岛外区域和黄河口外洼地区域DO较低也主要是由2014年跃层持续较长导致，表明跃层持续时间是影响氧亏损年际差异的重要因素。本文中氧亏损年际差异的分析结果，可为将来渤海底层DO季节预测提供参考，具有一定的指导意义。 |
| 关键词: 氧亏损 年际差异 跃层持续时间 黄河径流 渤海 |
| DOI：10.11693/hyhz20200800227 |
| 分类号:P734 |
| 基金项目:国家重点研发计划重点专项，2016YFC1401602号；国家自然科学基金项目，41806018号。 |
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| THE INTERANNUAL DIFFERENCE IN SUMMER BOTTOM OXYGEN DEFICIENCY IN BOHAI SEA |
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LI Zhi-Cheng1, WEI Hao1, ZHANG Hai-Yan1, ZHAO Hua-De2, ZHENG Nan2, SONG Gui-Sheng1
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1.School of Marine Science and Technology, Tianjin University, Tianjin 300072, China;2.National Marine Environmental Monitoring Center, Dalian 116023, China
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| Abstract: |
| The interannual difference of the spatial distribution of oxygen deficiency (OD) in bottom water in summer in Bohai Sea was analyzed, the OD near the mouth of the Laizhou Bay to the east of the Huanghe (Yellow) River estuary was revealed for the first time based on the observation data of Year 2014 and 2019, and the controlling factors of the interannual difference was explored by implementing a three-dimensional physical-biological coupled model ROMS-CoSiNE. Results show that the OD area where dissolved oxygen (DO) saturation was below 70% off Qinhuangdao City expanded to the east in 2014 while to the southeast in 2019. The OD area outside the Huanghe River estuary located mainly in a deep water depression on the southwest side of the central bank in 2014, while it extended from the depression on the western side of the central bank to the area off the estuary and the Laizhou Bay mouth. The estimation of oxygen budget in the bottom water during the existence of pycnocline showed that vertical diffusion and biological oxygen consumption were the main source and sink, respectively. The interannual OD difference in spatial distribution off Qinhuangdao in 2014 and 2019 was related to the difference due to weak vertical diffusion, leading to considerable DO decrease in rate and amount, and finally the stronger OD. In 2019, the OD near the Laizhou Bay mouth was due to vertical diffusion and duration of pycnocline. Strong Huanghe River runoff and south wind promoted the extension of the diluted water, and resulted in stronger pycnocline, weaker vertical diffusion, larger DO reduction rate, longer pycnocline duration, and finally stronger OD than those in 2014. In addition, lower DO in the area off Qinhuangdao and the depression area off the Huanghe River estuary in 2014 was resulted mainly from the longer duration of pycnocline in the year, indicating that the duration of pycnocline was an important factor affecting the interannual difference of OD. This study provided a reference for seasonal prediction of bottom DO in Bohai Sea in the future. |
| Key words: oxygen deficit interannual difference pycnocline duration Huanghe River runoff Bohai Sea |
