Sea ice algae chlorophyll a concentrations derived from under‐ice spectral radiation profiling platforms
Sea ice algae chlorophyll a concentrations derived from under‐ice spectral radiation profiling platforms
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来自冰下光谱辐射分析平台的海冰藻类叶绿素 a 浓度
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
H. Flores
中科院分区：
文献类型：
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作者：
B. Lange;C. Katlein;M. Nicolaus;I. Peeken;H. Flores
随着自然环境的不断变化，多尺度海冰藻类观测对于预测海冰生态系统的变化至关重要。在这项研究中，我们发展了先前建立的从光谱辐射测量中获得海冰藻类叶绿素a浓度（chl a）的方法，并将这些方法应用于更大规模的光谱调查。我们进行了四种不同的冰下光谱测量：辐照度、辐照度、透射率和透射率，并应用了三种统计方法：经验正交函数（EOF）、归一化差分指数（NDI）和多重NDI。我们基于2011年和2012年两次北冰洋中部巡航期间的冰芯chl a和同步光谱辐照/透射率（N = 49）和辐射/透射率（N = 50）测量开发了模型。根据两个标准对这些参考模型进行排名：平均稳健性R2和真实预测误差估计。对于估计大规模数据集的生物量，EOF方法比NDI方法表现得更好，因为它能够解释大范围内经历的环境特性的高变异性。基于鲁棒性和真实预测误差，将eof透射率、eof透射率和ndi透射率这三种最可靠的模型应用于两次遥控潜水器（ROV）和两次表面和冰下拖网（SUIT）的光谱辐射测量。在这些更大规模的chl a估计中，eof透射率显示出与冰芯chl a的最佳拟合。将我们最可靠的模型eof透射率应用于85 m水平ROV样带，与同一地点发表的生物量估计相比，发现了巨大的差异，这对整个北极冰藻生物量和初级产量的预测具有重要意义。
Multiscale sea ice algae observations are fundamentally important for projecting changes to sea ice ecosystems, as the physical environment continues to change. In this study, we developed upon previously established methodologies for deriving sea ice-algal chlorophyll a concentrations (chl a) from spectral radiation measurements, and applied these to larger-scale spectral surveys. We conducted four different under-ice spectral measurements: irradiance, radiance, transmittance, and transflectance, and applied three statistical approaches: Empirical Orthogonal Functions (EOF), Normalized Difference Indices (NDI), and multi-NDI. We developed models based on ice core chl a and coincident spectral irradiance/transmittance (N = 49) and radiance/transflectance (N = 50) measurements conducted during two cruises to the central Arctic Ocean in 2011 and 2012. These reference models were ranked based on two criteria: mean robustness R2 and true prediction error estimates. For estimating the biomass of a large-scale data set, the EOF approach performed better than the NDI, due to its ability to account for the high variability of environmental properties experienced over large areas. Based on robustness and true prediction error, the three most reliable models, EOF-transmittance, EOF-transflectance, and NDI-transmittance, were applied to two remotely operated vehicle (ROV) and two Surface and Under-Ice Trawl (SUIT) spectral radiation surveys. In these larger-scale chl a estimates, EOF-transmittance showed the best fit to ice core chl a. Application of our most reliable model, EOF-transmittance, to an 85 m horizontal ROV transect revealed large differences compared to published biomass estimates from the same site with important implications for projections of Arctic-wide ice-algal biomass and primary production.
通过高光谱水下辐射测量估算相对藻红蛋白浓度——统计方法
影响因子：
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作者：
Taylor;M. H. Taylor;T. Dinter;A. Bracher
通讯作者：
A. Bracher