太湖梅梁湾漫衰减系数季节性差异及其主导因素

利用2006-08-16、2007-3-28和2007-11-12三次在太湖梅梁湾15个样点的观测数据,对漫衰减系数(Kd)及其影响因素的时空差异性进行分析,发现:梅梁湾地区Kd的主要决定因素是总吸收系数,后向散射作用对Kd具有一定的影响作用,但非主导作用;梅梁湾地区水体Kd影响因素的主次关系并非固定不变,而是随着水体组分的季节性变化而变化,3月份Kd的主导影响因素是非色素物质,其次是有色可溶性有机物(CDOM)、色素物质和后向散射作用,而8月份的主导影响因素是色素物质,其次是非色素物质、CDOM和后向散射作用,而11月份相对较为复杂,在440nm处主导影响因素是非色素物质,其次是色素物质、CDOM和后向散射作用,595nm处主导影响因素是非色素物质吸收作用,其次是色素物质吸收作用、后向散射作用、CDOM吸收作用,675nm处主导影响因素是色素物质,其次是非色素物质、后向散射作用和CDOM.

Seasonal characteristics of the diffuse attenuation coefficient of Meiliang Bay waters and its primary contributors

For waters of Meiling Bay, Taihu Lake, field measurements were carried out Aug. 16, 2006, March 28 and Nov.12,2007. These measurements included diffuse attenuation coefficient of downwelling irradiance, absorption coefficients of pigments and non-pigments (aph and ad, respectively), and the colored dissolved organic matter (aCDOM), and backscattering coefficients (bb). For the total of 15 stations that have Kd, aph, ad, aCDOM, and bb, it is found that the primary contributor to Kd is absorption coefficient. bb does contribute to Kd, but in a minor role. Also, it is found that this relative significance in contributing to Kd varies seasonally. In March, the order of major to minor contributors was ad, aCDOM, and aph, and then bb. In August, this order became aph, ad, aCDOM, and then bb. It is more complicated in November, as at 440 nm, the order is ad, aph and aCDOM, and bb; at 595 nm, the order is ad and aph, bb, and aCDOM; at 676 nm, however, the order became aph and ad, bb, and then aCDOM.