太湖不同叶绿素a浓度水体荧光特征分析

Fluorescence Characteristics of Different Chlorophyll a Concentration in Lake Taihu

利用2008年太湖蓝藻爆发的5—8月实测的27个站点水体光谱反射率和水质参数,分析了不同叶绿素a浓度等级下太湖水体光谱的荧光特征。结果表明,荧光峰位置和荧光峰高度都与叶绿素浓度呈显著正相关,且荧光峰峰值位置和半宽度与叶绿素a浓度的拟合度要高于基线荧光峰高度和归一化荧光峰高度。荧光峰特性用于二类水体中高浓度叶绿素探测较传统的蓝绿光波段比值有很大的改进,而宽通道卫星遥感所采用的叶绿素浓度近红外红光波段比值法本质上与归一化荧光峰高度一致。这为今后进一步利用荧光特征提高太湖叶绿素a浓度反演精度提供了研究基础。

The spectral reflectance and water qualities of 27 stations were acquired in the lake Taihu during the months from May to August,2008 when blue algal bloomed.Based on the fluorescence characteristics analysis of different chlorophyll a concentration,it was obvious that the position and height of fluorescence peak both have a positive correlation with chlorophyll a concentration,and the correlation coefficients between chlorophyll a concentration and position and half width of fluorescence peak are larger than those of the reference baseline and the normalized height of fluorescence.Estimating of chlorophyll a concentration in case 2 water using fluorescence characteristics is obviously better than the empirical algorithm based on blue to green ratio.Moreover,the common algorithm based on near infrared band to red band ratio is essentially consistent with the normalized height method.