| 辽河流域氮素时空分布及其对土地利用和降雨的响应 |
| 摘要点击 477 全文点击 89 投稿时间：2023-04-30 修订日期：2023-06-23 |
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| 中文关键词 辽河流域 总氮 氨氮 土地利用 强降雨 |
| 英文关键词 Liaohe River Basin total nitrogen ammonia nitrogen land use heavy rainfall |
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| 中文摘要 |
| 为了制定更有效的氮污染治理措施,基于辽河流域2016~2022年国控断面水质数据,利用Spearman相关性分析和非线性拟合的分析方法并结合2020年水文气象和土地利用遥感数据,对辽河流域的氮素时空分布特征及其对不同尺度下土地利用类型和降雨的响应进行了研究.结果表明：①在时间上,7年来总氮浓度整体呈上升趋势,氨氮浓度呈下降趋势.总氮和氨氮浓度呈明显季节规律,其中总氮浓度在秋冬季节高,在春夏季节低；氨氮浓度在春冬季节高,在夏秋季节低.②空间上,总氮浓度呈西高东低分布；氨氮浓度呈中间高四周低分布.汇入支流和上游发源地总氮浓度过高,可能分别是辽河流域西部小凌河流域和饶阳河流域总氮浓度高的原因.③农田和城市用地是氮素升高的主要影响因素,森林对氮素具有净化作用.土地结构对总氮在小尺度、枯水有更好的解释能力,而氨氮在大尺度、丰水有更好的解释能力.④强降雨发生之后,氮素浓度通常在当天或雨后1~5 d内达到峰值.随着降雨强度的增加,氮素浓度呈现先增加后减少的趋势. |
| 英文摘要 |
| In order to develop more effective strategies for controlling nitrogen pollution, this study investigated the spatiotemporal distribution of nitrogen in the Liaohe River Basin and its relationship with land use types and precipitation at various scales. The research was based on water quality data from state-controlled cross-sections within the Liaohe River Basin between 2016 and 2022, employing Spearman correlation analysis and non-linear fitting in conjunction with hydro-meteorological and land use remote sensing data from 2020. Key findings included ① temporal trends： Over the past seven years, there was an overall increase in total nitrogen concentration and a decrease in ammonia nitrogen concentration. Seasonal patterns of total nitrogen and ammonia nitrogen concentrations were evident, with total nitrogen concentrations higher during autumn and winter and lower in spring and summer. However, ammonia nitrogen concentrations were higher in spring and winter and lower in summer and autumn. ② Spatial distribution： Total nitrogen concentrations exhibited a high-to-low gradient from west to east, whereas ammonia concentrations were high in the central region and low in the surrounding areas. Elevated total nitrogen concentrations in the confluences of tributaries and upstream headwaters potentially contributed to the high concentrations of total nitrogen observed in the Xiaoling River Basin and the Rao Yang River Basin. ③ Land use impact： Agricultural and urban land use were significant factors influencing nitrogen concentrations, whereas forests had a mitigating effect on nitrogen levels. The land structure exhibited stronger explanatory power for total nitrogen at smaller scales and under dry conditions, whereas ammonia nitrogen demonstrated better explanatory power at larger scales and in water-rich environments.④ Precipitation effect： Following intense rainfall events, nitrogen concentrations generally peaked on the same day or within one to five days after the precipitation. As the intensity of rainfall increased, nitrogen concentrations displayed a pattern of increasing before subsequently decreasing. |
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