| 一种基于GOCI数据的叶绿素a浓度三波段估算模型 |
| 摘要点击 2551 全文点击 1320 投稿时间：2015-01-08 修订日期：2015-04-02 |
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| 中文关键词 GOCI 内陆二类水体 叶绿素a浓度 三波段 |
| 英文关键词 GOCI inland case 2 water chlorophyll-a concentration three band model |
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| 中文摘要 |
| 以标准三波段算法为基础,构建了适用于GOCI影像数据的叶绿素a浓度三波段估算模型. 并以三峡水库、巢湖、洞庭湖和太湖水体的289组实测叶绿素a浓度以及光谱数据作为基础,模拟了GOCI影像和MERIS影像波段,率定了模型参数,并与MERIS三波段算法和目前常用的GOCI波段比值算法进行了对比分析,最终用GOCI影像数据进行了独立数据验证. 结果表明:① 对目前的数据集,680 nm处和660 nm处的色素颗粒物吸收系数具有相对固定的比例关系,比值为1.351; ② GOCI三波段模型在模型率定中,得到与MERIS三波段模型近似的效果,线性拟合的决定系数为0.809,略低于MERIS三波段模型的0.820,但明显优于GOCI比值模型(0.450),有效避免了GOCI波段比值模型中在叶绿素a浓度低值区出现的"扩散"现象,体现出较好的普适性; ③ 通过验证数据集中平均相对误差和均方根误差两个误差指标的对比,发现GOCI三波段模型误差表现与建模数据一致,与MERIS数据接近,明显优于GOCI波段比值模型; ④ 通过GOCI影像的同步验证,发现GOCI波段比值算法会对太湖叶绿素a浓度产生明显的低估,且难以体现叶绿素a浓度空间变异. GOCI三波段算法效果相对较好. 相比于目前常用的波段比值算法,GOCI三波段算法具有更高的稳定性和精度,有较强的应用潜力. |
| 英文摘要 |
| A GOCI-based three band model is proposed for chlorophyll-a concentration estimation based on the classical three band model. The model was built based on 289 in-situ measured chlorophyll-a concentration and hyperspectral spectrums-simulated GOCI spectrums, and was compared with MERIS-based three band model and GOCI band ratio model. At last, the model was validated using several GOCI images and an independent in-situ sampling dataset. The results showed that: ① For the current dataset, the ratio of aph(680) and aph(660) was relatively stable. ② The GOCI-based three band algorithm had a similar performance with MERIS-based three band algorithm in the modeling dataset. The R2 value of the GOCI-based three band model was 0.809, which was a little lower than that of the MERIS-based three band model (R2=0.820), but was obviously higher than that of GOCI band ratio model (R2=0.450). ③ The performance of GOCI-based three band model in the validation dataset was similar with that in the modeling dataset, which was close to that of the MERIS-based three band model, and significantly better than that of GOCI band ratio model. ④ The GOCI image data validation indicated that GOCI band ratio model would clearly underestimate chlorophyll-a concentration in Taihu Lake. The spatial difference of chlorophyll-a concentration that yielded by the band ratio model was not clear. Compared with the widely used band ratio algorithm, the GOCI-based three band algorithm has higher stability, better accuracy, and stronger potential in application. |
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