滇池水华分形结构动态研究

Dynamics Study on Fractal Structure of Cyanobacteria Bloom in Dianchi

采用MODIS-NDVI数据,运用CART分枝树法将滇池水体分成富集区、过渡区和水面,依据分形理论对滇池水域不同分区微景观镶嵌体的分维数进行计算,揭示其分维特征,结果表明:滇池水体微景观镶嵌体具有统计意义上的自相似性,是一种随机分形结构,微景观的分维值越大,其形态越复杂,反之越简单。滇池99.7%面积属于富营养区,滇池水华形态稳定性:过渡区>富集区>水体;形态复杂性:水体>富集区>过渡区。分形结构特征反映了滇池水体微景观格局要素镶嵌结构的复杂性与稳定性,有利于认识滇池水华在空间上的镶嵌规律及作用机制,对监测和预测蓝藻水华的暴发具有重要意义,也为滇池生态环境的保护和可持续发展提供科学依据。

Lake Dianchi was divided into three parts including concentrated area,transition area and water area through CART tree method with MODIS-NDIV data.The fractal theory was used to calculate the fractal value of micro-landscape mosaic in different areas,and reveal the fractal characteristics.Results indicated that micro-landscape mosaic of the Lake has statistical self-similarity and its fractal dimension value is a kind of random fractal geometry.Bigger the fractal dimension value with the more complex morphology,so as the smaller.99.7%of the Lake area falls into the concentrated area,with morphology stability as transition area,concentrated area and water area,while morphology complexity as water area,concentrated area and transition area.The fractal characteristics reflected the complexity and stability of micro-landscape mosaic structure of the Lake,which would help to understand the law of mosaic in spatial and reaction mechanism of cyanobacterial bloom in the Lake,and had great significance of monitoring and forecasting the cyanobacterial bloom,also provided a scientific basis for protecting the ecological environment and sustainable development of the Lake.