静止水体中微囊藻属迁移轨迹的数值模拟

中国环境科学2017,37(5)：1915~1921ChinaEnvironmentalScience静止水体中微囊藻属迁移轨迹的数值模拟俞茜1,2,陈永灿3,4,刘昭伟4*(1.中国水利水电科学研究院,北京100038；2.水利部防洪抗旱减灾工程技术研究中心,北京100038；3.西南科技大学环境与资源学院,四川绵阳621010；4.清华大学,水沙科学与水利水电工程国家重点实验室,北京100084)摘要：通过建立水质模型与微囊藻属浮力调节模型相结合的复合模型,模拟微囊藻属在静止水体中的迁移轨迹.模拟结果表明:微囊藻属在不同水深的水体中呈现不同的迁移轨迹.当水深较浅,大量光强可以直射水底时,不同直径大小的微囊藻群体均沉降在水底;当水深较深时,不同直径大小的微囊藻群体均在水深方向周期性上浮下沉运动.群体直径大小决定微囊藻属的垂向迁移幅度,直径越大的微囊藻群体在水深方向的迁移幅度越大.消光系数决定微囊藻属的迁移中心位置,消光系数小,微囊藻属在水深较深处运动;消光系数大,微囊藻属在靠近水面处运动.关键词：微囊藻属；迁移轨迹；浮力调节；消光系数；数值模拟中图分类号：X173,X52文献标识码：A文章编号：1000-6923(2017)05-1915-07ModellingverticalmigrationtrajectoryofMicrocystisincalmwater.YUQian1,2,CHENYong-can3,4,LIUZhao-wei4*(1.ChinaInstituteofWaterResourcesandHydropowerResearch,Beijing100038,China；2.CenterofDisasterReductionoftheMinistryofWaterResources,Beijing100038,China；3.SchoolofEnvironmentandResource,SouthwestUniversityofScienceandTechnology,Mianyang621010,China；4.StateKeyLaboratoryofHydroscienceandEngineering,TsinghuaUniversity,Beijing100084,China).ChinaEnvironmentalScience,2017,37(5)：1915~1921Abstract：Inthispaper,amathematicalmodelcouplingbuoyancyregulationmodelandhydrodynamicmodelwasdevelopedtosimulatethetrajectoryofMicrocystiscoloniesincalmwater.ThesimulationresultsshowedthatMicrocystispresentdifferentmovementtrajectoriesinwaterwithdifferentdepths.Inshallowwaterwherelargeamountsofincidentlightcouldreachatthebottomofwater,alltheMicrocystiscolonies,whateversizetheyhave,stayedatthebottom.However,indeepwater,againwhateversizetheyhave,Microcystiscoloniesmadeperiodicalmovements.Thesimulationresultsrevealedthatcolonysizewasthemainfactorthatdeterminedthetrajectoryamplitudeinthevertical.TheMicrocystiscolonywithlargersizewouldreachdeeperpositionsandalsoreachwatersurface.Extinctioncoefficientsdeterminedthemovementposition.Iftheextinctioncoefficientwassmall,Microcystiscolonieswouldmoveinthedeeperposition.Onthecontrary,iftheextinctioncoefficientwaslarge,thecolonieswouldmovenearthewatersurface.Keywords：Microcystis；migrationtrajectory；buoyancyregulation；extinctioncoefficie