基于GIS的滇池外海叶绿素a时空分布特征分析

Spatial and Temporal Distribution of Chlorophyll a in Dianchi Lake Based on GIS

为掌握滇池外海叶绿素a时空分布特征,基于2022年滇池外海27个监测点位每月1次叶绿素a实测数据,利用ArcGIS中3种不同方法进行空间插值,通过交叉验证选取插值精度较高的普通克里金法对滇池外海叶绿素a时空分布特征进行了分析。结果表明:滇池外海叶绿素a具有明显空间异质性和季节变化特征,从空间上看,呈北部区域>南部区域>中部区域,最高值出现在外海北部湖湾区域;从季节上看,呈秋季>冬季>夏季>春季的趋势。滇池外海叶绿素a不同季节的空间分布存在明显空间异质性,各个季节叶绿素a峰值浓度均出现在外海北部区域,尤其是外海北部湖湾及3个半岛附近水域,其中冬季在外海南部湖湾区域也出现较高浓度。滇池外海蓝藻水华在秋季暴发的可能性最大,外海北部湖湾区域蓝藻暴发的高风险区域,外海南部湖湾区在冬季也存在蓝藻水华发的风险。

In order to master the temporal and spatial distribution characteristics of chlorophyll-a in Dianchi Lake,three different spatial interpolation methods were used in ArcGIS based on monthly chlorophyll-a measurements at 27 monitoring sites in 2022.Cross-validation was used to select ordinary kriging,which had higher interpolation accuracy to analyze the spatiotemporal distribution characteristics of chlorophyll-a concentration in Lake Dianchi.The results showed that chlorophyll-a in Waihai exhibited significant spatial heterogeneity and seasonal variation.From a spatial perspective,the chlorophyll-a concentration was higher in the northern region than the southern region and the central region,with the highest value appearing in the northern lake bay region of Waihai.From a seasonal perspective,the chlorophyll-a concentration showed a trend of autumn>winter>summer>spring.The spatial distribution of chlorophyll-a in Dianchi Lake showed significant spatial heterogeneity in different seasons,with the peak concentration of chlorophyll-a appearing in the northern area of Waihai in any seasons,especially in the waters around the northern bay of Waihai and the three peninsulas.In winter,high concentration also appeared in the southern bay area of Waihai.The Dianchi Lake algal bloom is most likely to erupt in autumn,and the Lake-Bay area in the north of Waihai is at high risk of algal bloom,and the Lake-Bay area in the south of Waihai is also at high risk of algal bloom outbreak in winter.