Delta-X: In Situ Water Surface Reflectance across MRD, LA, USA, 2021, Version 2

This dataset includes above water measurements of remote-sensing reflectance measured in situ at field sampling stations during the Delta-X 2021 field efforts. Measurements were collected in the Atchafalaya River and Terrebonne Basins on the southern coast of Louisiana from 2021-03-25 to 2021-04-22 (spring) and from 2021-08-14 to 2021-09-24 (fall). Field sampling was paused on 2021-08-25 and resumed on 2021-09-13 due to the landfall of Hurricane Ida on 2021-08-26 approximately 70 km east of the study site. Water quality changes caused by the hurricane were expected to be minimal. 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 >100 m), near Delta-X intensive study sites, in open bays and lakes, and at a few locations in the nearshore Gulf of Mexico. For each in situ collection, a handheld Portable SpectroRadiometer (PSR-1100f, Spectral Evolution) was used to measure radiance from: (a) a highly reflective (>99% reflectance) Lambertian Spectralon panel (b) from the sky, measured at 40 degrees from the solar zenith and at 135 degrees from the sun azimuthal plane, (c) 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 and the water-leaving radiance relative to downwelling irradiance, including a correction for the influence of reflected skylight. These data are provided in comma-separated values (CSV) format.

本数据集收录了在Delta-X 2021野外考察期间，于现场采样站实地测量的遥感反演辐射度测量值。测量数据采集自路易斯安那州南部海岸的阿查法拉亚河和特雷博恩盆地，时间跨度为2021年3月25日至4月22日（春季）以及2021年8月14日至9月24日（秋季）。由于2021年8月26日飓风Ida在研究地点东约70公里处登陆，导致2021年8月25日暂停采样，并于2021年9月13日恢复。预计飓风引起的水质变化将微乎其微。在多个不同宽度（从几米到超过100米）的河道、开阔海湾和湖泊，以及墨西哥湾近岸的若干地点，与现场样品采集和水中沉积物参数的测量同步进行反演辐射度的测量。对于每一次实地采集，使用手持式便携光谱辐射计（PSR-1100f，光谱进化公司）测量了以下来源的辐射度：（a）高反射率（>99%反射率）的朗伯光谱反射板；（b）天空中的辐射度，测量角度分别为太阳天顶40度和太阳方位角135度；（c）水面上的辐射度，测量角度分别为天顶40度和太阳方位角135度。这些测量数据被用于计算遥感反演辐射度和相对于入射辐照度的水面辐射度，包括对反射天空光影响的校正。这些数据以逗号分隔值（CSV）格式提供。