摘要
适宜太湖蓝藻水华大面积形成的诸多因素中,气象因素主要是高温、微风.据此对太湖周边17个常规气象观测站的7年报文资料进行筛选,选择的17个站点同时满足时间为14点、气温大于25℃、风速小于等于4m/s的风场进行分析,研究发现太湖流域风场空间特征以东南风居多,而且不同风向的背景风场吹过水面后,在下风向湖面及湖岸附近都存在明显的辐散,其散度中心出现在长兴、西山和宜兴构成的三角形区域.对无锡、宜兴、东山和吴县四个站同时满足上述条件的天数进行统计分析,发现太湖流域风场时间特征表现为:1982年之前每年高温微风天气出现的天数少而且出现的时间迟,而2004年之后出现的天数多而且出现的时间早,在1982-2004年之间出现的天数和出现的时间相对于历史平均值都呈振荡状态.
High temperature and gentle breeze were one of the key factors for the algae bloom formation in Lake Taihu.The days when temperature was higher than 25℃ at 14:00 and wind speed was less than 4 m/s at the same time were selected,and EOF analysis,cluster analysis of eight directions and divergence spatial distribution were used for studying the wind field from 17 meteorological stations in 2001-2007 around Lake Taihu.The spatial characteristics of selected wind field showed that the southeast wind was the major pattern.When any direction wind passed across the lake,the significant divergence appeared above the downwind lake surface and near its banks.The divergence field center was observably in the southwest area of Lake Taihu.Furthermore,statistical analysis on the observational data from 4 meteorological stations,such as Wuxi,Yixing,Dongshan and Wuxian,with days meeting the above-mentioned weather conditions,was put forward during 1961-2007.The numbers of days with high temperature and gentle breeze per year were less and the beginning time of such weather conditions was later before 1982.Oppositely,the numbers of such days per year was more and the beginning time was earlier after 2004.Both of them showed oscillation during 1982 to 2004.
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2011年第1期122-128,共7页
Journal of Lake Sciences
基金
国家重点基础研究发展计划项目(2008CB418003)
江苏省环境监测科研基金项目(0919)
解放军理工大学基础理论研究基金项目联合资助
关键词
蓝藻水华
EOF
聚类分析
热力环流
风场
辐散
太湖流域
Algae bloom
EOF
cluster analysis
thermal circulation
wind field
divergence
Taihu Basin