| 摘要: |
| 为研究丹江口水库热分层对溶解氧垂向分布的影响，本文通过2023年丹江口水库13个断面逐月垂向水温及溶解氧浓度监测，基于溶解氧需求侧分析了丹江口水库水体热分层期溶解氧垂向分布的影响因素以及水库缺氧区形成的原因。结果表明：2023年5—10月，丹江口水库存在显著的热分层现象，水库热分层主要出现在水体表层5.00~10.00m处，汉江库区部分断面在水体中层存在第二个温跃层；热分层是溶解氧层化结构形成的主要原因，表层水体的溶解氧分层随着水体热分层的发展普遍在7月开始出现，水体中层的温跃层在热分层初期的5月就形成了溶解氧分层，溶解氧分层出现的位置及变化趋势与热分层高度相似，在热分层末期溶解氧层化结构随着热分层的消退而消失；缺氧区出现在丹江库区外围以及汉江库区中下段，由于热分层存在时间较长且分层稳定，水体下层溶解氧补充长期受限，加上水体自身耗氧作用，底层水体在8—10月陆续开始形成缺氧区，进入11月水库垂向混合完成，缺氧区完全消失。研究揭示了水库热分层作用对丹江口水库溶解氧垂向分布的驱动作用，对深入理解丹江口水库水质演变及生态演替过程具有重要作用。 |
| 关键词: 丹江口水库 热分层 成因分析 溶解氧层化结构 缺氧区 |
| DOI： |
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| 基金项目:国家自然科学(52179057)、湖北省自然科学基金杰出青年项目(No.2023AFA056)和中央级公益性科研院所基本科研业务费(CKSF2023337/SH)联合资助. |
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| Characteristics of vertical distribution and causes of dissolved oxygen during thermal stratification in Danjiangkou Reservoir based on the perspective of dissolved oxygen demand side |
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HUANG Dingyang, LIN Li, PAN Xiong, DONG Lei
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Basin Water Environmental Research Department, Changjiang River Scientific Research Institute
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| Abstract: |
| In order to explore the effect of Danjiangkou Reservoir thermal stratification on the vertical distribution of dissolved oxygen, this paper selected the measured values of monthly vertical water temperature and dissolved oxygen concentration in 13 sections of the Danjiangkou Reservoir in 2023 to analyze the influencing factors of the vertical distribution of dissolved oxygen during thermal stratification and the reasons for the formation of anoxic zones, based on the dissolved oxygen demand side. Results show that there is significant thermal stratification in the Danjiangkou Reservoir from May to October. Thermal stratification in the reservoir mainly occurs at 5.00~10.00m on the surface water. Some sections in the Hanjiang Reservoir area have a second thermocline in the middle layer of the water. Thermal stratification is the main reason for the formation of the dissolved oxygen stratification structure. The dissolved oxygen stratification of the surface water generally begins to appear in July with the development of the thermal stratification. The thermocline in the middle layer of the water has formed dissolved oxygen stratification in May. The location and changing trend of dissolved oxygen stratification are highly similar to thermal stratification. At the end of thermal stratification, the dissolved oxygen stratification structure subsides with thermal stratification. Anoxic zones appear in the periphery of the Danjiang Reservoir and in the middle and lower reaches of the Hanjiang Reservoir. Due to the long-term existence of thermal stratification and the stable stratification, the dissolved oxygen supplementation in the lower layers of the water has been limited for a long time, plus the oxygen consumption of the water, the bottom water began to form anoxic zones from August to October. In November, the vertical mixing was completed and the anoxic zone disappeared. The study revealed that the thermal stratification of the reservoir strongly drives the vertical distribution of dissolved oxygen in the Danjiangkou Reservoir, which is important for a deep understanding of the water quality evolution and ecological succession process of the Danjiangkou Reservoir. |
| Key words: Danjiangkou Reservoir thermal stratification cause analysis dissolved oxygen stratification anoxic zone |
