A simple semi-analytical model for remote estimation of chlorophyll-a in turbid waters:: Validation
A simple semi-analytical model for remote estimation of chlorophyll-a in turbid waters:: Validation
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DOI：
10.1016/j.rse.2008.04.015
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发表时间：
2008-09-15
影响因子：
13.5
通讯作者：
Holz, John
中科院分区：
文献类型：
--
作者：
Gitelson, Anatoly A.;Dall'Olmo, Giorgio;Holz, John
由于第2类水域的光学复杂性，利用遥感手段准确评估浑浊水域中的浮游植物叶绿素a(Chla)浓度具有挑战性。我们应用了最近发展的[R-Rs(-1)(lambda(1))-R-rs(-1)(lambda(2))]×R-rs(lambda(3))形式的模型，其中R-Rs(lambda(I))是波长为lambda(I)的遥感反射率，用于估算浑浊水体中的Chla浓度。本文的目的是：(A)利用在浑浊湖泊、水库、河口和沿海水域的相当大范围的光学性质、营养状况和地理位置收集的数据集，验证三波段模型及其特例--两波段模型R-Rs(-1)(lambda(1))×R-Rs(lambda(3))。利用中分辨率成像光谱仪的3个光谱波段(波长660~670 nm、703.75~713.75 nm和750~757.5 nm)对三波段模型进行了定标和验证，并用两个中分辨率成像光谱仪的光谱手(lambda(1)=662~672，lambda(3)=743~753 nm)对两波段模型进行了检验。我们在四个独立的数据集中评估了CHLA预测的准确性，而不需要在其他地方进行初始校准后的重新参数化(调整系数)。尽管验证数据集包含变化很大的CHLA(1.2到236 mg m(-3))、Secchi盘深度(0.18到4.1m)和浊度(1.3到78 NTU)，但由三波段算法预测的CHLA与观测到的CHLA(r(2)和gt；0.96)具有很强的相关性，精度为32%，数据集的平均偏差为-4.9%到11%。双波段算法预测的CHLA也与观测CHIN密切相关(r(2)>；0.92)；然而，精度下降到57%，数据集的平均偏差为19%到50.3%。这些发现意味着，如果对红色和近红外波段的大气校正方案可用，MERIS和MODIS图像的广泛数据库可用于对CHLA浑浊水域的定量监测。(C)2008 Elsevier Inc.保留所有权利。
Accurate assessment of phytoplankton chlorophyll-a (chla) concentrations in turbid waters by means of remote sensing is challenging due to the optical complexity of case 2 waters. We have applied a recently developed model of the form [R-rs(-1)(lambda(1))-R-rs(-1)(lambda(2))] x R-rs(lambda(3)) where R-rs(lambda(i)) is the remote-sensing reflectance at the wavelength lambda(i), for the estimation of chla concentrations in turbid waters. The objectives of this paper are (a) to validate the three-band model as well as its special case, the two-band model R-rs(-1)(lambda(1)) x R-rs(lambda(3)), using datasets collected over a considerable range of optical properties, trophic status, and geographical locations in turbid lakes, reservoirs, estuaries, and coastal waters, and (b) to evaluate the extent to which the three-band Model Could be applied to the Medium Resolution Imaging Spectrometer (MERIS) and two-band model Could be applied to the Moderate Resolution Imaging Spectroradiometer (MODIS) to estimate chla in turbid waters.The three-band model was calibrated and validated using three MERIS spectral bands (660-670 nm, 703.75-713.75 nm, and 750-757.5 nm), and the 2-band model was tested using two MODIS spectral hands (lambda(1) = 662-672, lambda(3) = 743-753 nm). We assessed the accuracy of chla prediction in four independent datasets without reparameterization (adjustment of the coefficients) after initial calibration elsewhere. Although the validation data set contained widely variable chla (1.2 to 236 mg m(-3)), Secchi disk depth (0.18 to 4.1 m), and turbidity (1.3 to 78 NTU), chla predicted by the three-band algorithm was strongly correlated with observed chla (r(2) > 0.96), with a precision of 32% and average bias across data sets of -4.9% to 11%. Chla predicted by the two-band algorithm was also closely correlated with observed chin (r(2) > 0.92); however, the precision declined to 57%, and average bias across the data sets was 19% to 50.3%. These findings imply that, provided that an atmospheric correction scheme for the red and NIR bands is available, the extensive database of MERIS and MODIS imagery could be used for quantitative monitoring of chla turbid waters. (C) 2008 Elsevier Inc. All rights reserved.