2002-2018年滇池外海蓝藻水华暴发时空变化特征及其驱动因子

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 2002-2018年滇池外海蓝藻水华暴发时空变化特征及其驱动因子 DOI: 10.5846/stxb202110253002 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 云南大学（C176220100043）；云南省科技厅（202001BB050078）；国家自然科学基金（41671205）；滇池管理局"滇池蓝藻监控预警系统及平台建设"（K207002003021） Spatio-temporal variation and driving factors of algal bloom at Lake Dianchi during 2002-2018 Author: Affiliation: Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为弄清滇池外海蓝藻水华暴发时空变化规律及其影响因素，将滇池外海分为北、中、南3个区域，基于2002-2018年期间中分辨率成像光谱仪（MODIS）反演的水华面积，分析了上述3个区域蓝藻水华的时空变化特征。基于2007-2018年水文、气象和出入流数据，构建了外海三维水动力生态模型（AEM3D），并计算了各区域的水力滞留时间。通过冗余分析（RDA）、随机森林（RF）和斯皮尔曼相关分析方法，分析了影响以上区域蓝藻水华暴发的主要驱动因子。结果表明：2002-2018年期间，整个滇池外海区域年平均水华面积比（水华面积占该区域总面积比例）呈缓慢下降趋势，空间上由北向南依次递减，整个外海水华暴发面积最大主要发生在秋季。在外海北部区域，其东部水华较西部更为严重，而在中部和南部区域，呈现西部水华较东部更为严重的空间分布模式。通过对各影响因子的统计分析发现，风速、水温和日照时长是上述各区域中蓝藻水华暴发的主要决定性因素。水华暴发期间以西南风为主导风向，且上述区域的水华面积比随风速增加呈下降趋势。在外海各区域，水力滞留时间与水华暴发面积均呈显著正相关，空间上水力滞留时间由北向南逐渐增大，风速和风向是影响蓝藻水华空间分布规律和严重程度的主要因素。 Abstract:Algal bloom, which is caused by lake eutrophication, is one of the most serious environmental and ecological problems in the world. Lake Dianchi, the largest plateau freshwater lake in Yunnan Province, has experienced algal bloom events frequently in recent years. To understand the spatial and temporal variation pattern of algal bloom and to find the key driving factors, we divided the Waihai, Lake Dianchi into three zones (north, middle and south) according to the water quality monitoring points, and extracted algal bloom information from remote sensing images (Moderate Resolution Imaging Spectroradiometer, MODIS) for Waihai, Lake Dianchi during 2002-2018. Based on the hydrological and meteorological data in 2007-2018, Aquatic Ecosystem Model-3 Dimensional (AEM3D) was set up to calculate water residence time at the north, middle and south zones of Waihai, Lake Dianchi. Redundancy analysis (RDA), Random Forest (RF) and Spearman correlation analysis methods were adopted to identify the key driving factors for algal blooms at the north, middle and south zones of Waihai, Lake Dianchi. The results showed that the ratio of algal bloom area to the whole area at Waihai gradually decreased with obvious seasonality and spatiality with the largest ratio value in autumn mainly during 2002-2018. In the three zones, the ratio of algal bloom area to the zone area followed a spatial pattern of north > middle > south. At each zone, the ratio at the east was larger than that at the west in the north zone, whereas there was a reversed spatial distribution pattern for the middle and south zones of Waihai. The statistical analysis of meteorological and water quality factors with response factors (proportion of algal bloom area and chlorophyll a) showed that wind speed, water temperature and sunshine duration were the main driving factors of algal blooms for Waihai of Lake Dianchi. During the algal bloom period, as the speed of wind increased, the proportion of algal bloom area at the north, middle and south zones of Waihai showed a decreasing trend and the wind from southwest was the dominant direction. At the three zones, water residence time was positively correlated with algal bloom area and gradually increased from north to south. The water residence time at the west was longer than that at the east in the north zone, whereas there was no significant difference between the west and east in terms of the middle and south zones of Waihai. Wind speed and wind direction were the main factors affecting spatial variation and algal bloom area. 参考文献 相似文献 引证文献