摘要
以千岛湖为研究对象,利用高光谱地物光谱仪在库区进行了反射光谱测量和同步水质采样分析。通过研究水体藻类叶绿素浓度与其高光谱反射特征之间的关系,建立了叶绿素a的遥感定量模型,结果表明:光谱反射率比值R701nm/R516nm、IKONOS的红光与蓝光波段反射率之比与叶绿素a线性相关程度都比较高,决定系数分别为0.87和0.83,可以用来估计叶绿素a浓度;而微分光谱、单波段以及其它波段比与叶绿素a的相关性不及前两者。所以,遥感估算千岛湖叶绿素a浓度,采用比值法最准确。由于TM波段与IKONOS波段范围几乎完全相同,而分辨率不同,从经济实用的角度考虑,可以用TM数据对整个库区进行大范围遥感监测,而对其支流和小范围水面,用分辨率较高的IKONOS数据才能满足精度要求。
Qiandao Lake is the biggest freshwater reservoir of Zhejiang Province .This study was conducted to establish correlations between reflectance and concentration of chlorophyll-a in Qiandao Lake. Reflectance spectra was measured on July 4, 2001 using Fieldspec radiometer. Extensive water quality sampling was carried out simultaneously with the spectral data collection. The features of the spectral reflectance of the lake water were discussed. The reflectance ratio of R_(701nm)/R_(516nm) was found to be significantly correlated with the concentration of chlorophyll-a. It was also found that the correlation between the concentration of chlorophyll-a and the reflectance ratio of red/blue band of IKONOS data was also high, so it is possible to monitor the water quality of Qiandao Lake using remote sensing data.
基金
韩国HD.eIMAGE公司和杭州市环保局资助项目(H2001011705).
