Optical characterization of water masses within the Columbia River plume
Optical characterization of water masses within the Columbia River plume
复制标题
哥伦比亚河羽流内水团的光学特征
DOI：
10.1029/2012jc008005
复制
发表时间：
2012
影响因子：
--
通讯作者：
R. Kudela
中科院分区：
文献类型：
--
作者：
S. Palacios;T. D. Peterson;R. Kudela
哥伦比亚河羽流（CRP）是一种浮力羽流，它通过输送淡水、硅酸、微量金属、微粒和溶解的有机物质影响俄勒冈和华盛顿大陆架。高度动态的羽流包含亚中尺度特征，这些特征对化学、生物以及近海水和物质的运输有影响。较大的羽流水团的生物光学分类已经确认了季节性和年度流动模式，但由于没有现场数据来验证分类，因此没有以生物地球化学相关的方式描述羽流的内部结构。本研究的目的是利用生物地球化学和生物光学相关变量的原位测量来统计地定义CRP内的水类型，从这些水类型中建立一个训练数据集，并将该训练数据集应用于250米分辨率的中分辨率成像光谱仪（MODIS） Aqua图像，从海洋下降和上升时期预测区分羽流内的水团。本研究的分类技术在预测CRP中的水类型方面是有效的。三变量输入矩阵（温度、盐度和叶绿素荧光）在识别河口羽流内部精细尺度结构方面优于两变量输入矩阵（温度和盐度）。在河口和华盛顿大陆架上观察到羽流隆起和漩涡等保留特征。这种分类方法仅限于船上、系泊和卫星传感器测量的可用连续变量。在此分类器框架的基础上，提出了两种新的分类方法。
[1] The Columbia River plume (CRP) is a buoyant plume that influences the Oregon and Washington shelf with the delivery of freshwater, silicic acid, trace metals, and particulate and dissolved organic matter. The highly dynamic plume contains submesoscale features that have an impact on the chemistry, biology, and transport of water and material offshore. Bio-optical classification of the larger plume water mass has confirmed seasonal and annual flow patterns but has not described the internal structure of the plume in a biogeochemically relevant way, as there were no in situ data to validate classification. The objectives of this study were to define water types statistically within the CRP using in situ measurements of biogeochemically and bio-optically relevant variables, to build a training data set from these water types, and to apply this training data set to 250 m resolution Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua imagery from an oceanographically downwelling and upwelling period to predictively discriminate water masses within the plume. This study's classification technique was effective at predicting water types in the CRP. The three-variable input matrix (temperature, salinity, and chlorophyllafluorescence) performed better than the two-variable input matrix (temperature and salinity) at distinguishing fine-scale structure within the plume at the river mouth. Retentive features such as the plume bulge and eddies were observed at the river mouth and on the Washington shelf. This classification approach was limited to the available continuous variables measured by shipboard, mooring, and satellite sensors. Two new classification methods are proposed that build on the framework of the classifier described here.