Delta-X: In Situ Spectral Reflectance of Water Surface at MRD at LA, USA, Spring 2021

This dataset includes above water measurements of remote-sensing reflectance measured in situ at field sampling stations during the Delta-X 2021 Spring campaign. Samples were collected in the Atchafalaya River and Terrebonne Basins on the southern coast of Louisiana from 2021-03-25 to 2021-04-22 using a handheld Portable SpectroRadiometer (PSR-1100f). Reflectance is reported in the dataset as remote sensing reflectance at 1 nm intervals in the range 360 nm-900nm, with uncertainty reported for each wavelength. During the field campaign, reflectance was measured near-simultaneously with collection of field samples and in-water sediment parameters in multiple channels of varying width (from a few meters to >100m), near Delta-X intensive study sites, and in open bays and lakes and at few locations in the nearshore Gulf of Mexico. PSR-1100f, manufactured by Spectral Evolution, was used to measure radiance from: (1) a highly reflective (> 99% reflectance) Lambertian Spectralon panel, ( 2) from the sky, measured at 40 degrees from the solar zenith and at 135 degrees from the sun azimuthal plane, and ( 3) from the water, measured at 40 degrees from nadir and at 135 degrees from the sun azimuthal plane. These measurements were used to calculate remote-sensing reflectance, the water-leaving radiance relative to downwelling irradiance, including a correction for the influence of reflected skylight. At each station, measurement spectra of a single target (water, panel, or sky) were combined through the use of a median filter to create a single representative radiance measurement for the target from multiple spectra. This dataset is used to calibrate and validate Delta-X's algorithms used for the retrieval of total suspended solids concentration from AVIRIS-NG imagery and to inform and validate Delta-X's sediment transport models.

本数据集包含了在Delta-X 2021春季行动期间，于现场采样站实地测量的水面以上遥感反射率数据。采样工作于路易斯安那州南部海岸的阿切法拉亚河和特雷博恩盆地进行，时间跨度为2021年3月25日至2021年4月22日，采用手持便携式光谱辐射计（PSR-1100f）进行。数据集中报告的反射率以1纳米的间隔在360纳米至900纳米的范围内表示遥感反射率，并对每个波长的测量不确定性进行了报告。在野外行动期间，反射率与现场样品采集和多个不同宽度（从数米到超过100米）的水下沉积参数的测量同步进行，这些测量点位于Delta-X密集研究区域附近、开放海湾和湖泊以及墨西哥湾近岸的少数地点。Spectral Evolution公司制造的PSR-1100f用于测量来自以下三个来源的辐射亮度：（1）一个高反射率（>99%反射率）的朗伯光谱反射板，（2）来自天空，测量点位于太阳天顶角40度，太阳方位角平面135度，（3）来自水面，测量点位于正下方40度，太阳方位角平面135度。这些测量数据被用于计算遥感反射率，即相对于入射辐射度的水离开辐射亮度，包括对反射天空光影响的校正。在每个站点，通过使用中值滤波器将单一目标（水、面板或天空）的测量光谱组合，从而从多个光谱中创建单一代表性辐射亮度测量值。本数据集用于校准和验证Delta-X从AVIRIS-NG影像中提取总悬浮固体浓度的算法，并用于提供和验证Delta-X的沉积物运输模型的信息。