太湖水体光学衰减系数的分布及其变化特征

利用2001-2002年周年太湖全湖不同湖区湖泊光学的实测资料,分析了太湖水体光学衰减系数的区域分布,季节变化,垂直分布及日变化特征,并阐述了其变化原因,将太湖与国外一些湖泊进行对比,进一步阐述了太湖的光学特征.结果表明:光学衰减系数的湖区分布大致为:河口区>五里湖>湖心区>梅梁湾>贡湖>东太湖;由于不同湖区对光学衰减系数影响的主导因素不一样,其季节变化存在差异,东太湖季节变化不大,湖心区衰减系数秋冬季较大,而梅梁湖区则夏秋较大;衰减系数日变化则表现为中午大,上午和下午小;衰减系数的垂直分布主要有逐渐递减和先递减后均匀2种类型;衰减系数的光谱特性表现为在短波部分较大,长波部分较小,670nm处有一相对高值.

Analysis on distribution and variation of beam attenuation coefficient of Taihu Lake's water

Based on optical parameter data of different lake regions from 2001 to 2002 obtained in situ,the zonal distribution, the seasonal variation,the vertical distribution and the daily variation feature of beam attenuation coefficient are analyzed and the causes are explained.The attenuation coefficient,concentrations of chlorophyll-a(Chl-a) and total suspended matter (TSM) of Taihu Lake water and of some abroad lakes water are contrasted,which detailedly expounds the optical properties of Taihu Lake water body.The results show that the zone distribution of beam attenuation coefficient is estuary > Wuli Lake > Lake center,Lake center > Meiliang Lake,Meiliang Lake > Gonghu Lake,and Gonghu Lake > Easter Taihu Lake; the seasonal variations are different because the main affecting factors of beam attenuation coefficient at different zones are different; the beam attenuation coefficient at noon is bigger than that of morning and afternoon; there are two types of beam attenuation coefficient vertical distribution,one of which decreases step by step,the other decreases at first and varies little then; and the spectral properties of beam attenuation coefficient show that it is bigger at short wavelength than that of long wavelength and with a high value at 670nm.