Crocker Reef, Florida, 2017-2018 Seafloor Elevation Stability Models, Maps, and Tables

The U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted research to identify areas of seafloor elevation stability and instability based on elevation changes between the years of 2017 and 2018 at Crocker Reef near Islamorada, Florida (FL), within a 6.11 square-kilometer area. USGS SPCMSC staff used seafloor elevation-change data from Yates and others (2019) derived from an elevation-change analysis between two elevation datasets acquired in 2017 and 2018 using the methods of Yates and others (2017). A seafloor stability threshold was determined for the 2017-2018 Crocker Reef elevation-change dataset based on the vertical uncertainty of the 2017 and 2018 digital elevation models (DEMs). Five stability categories (which include, Stable: 0.0 meters (m) to ±0.24 m or 0.0 m to ±0.49 m; Moderately stable: ±0.25 m to ±0.49 m; Moderately unstable: ±0.50 m to ±0.74 m; Mostly unstable: ±0.75 m to ±0.99 m; and Unstable: ±1.00 m to Max/Min elevation change) were created and used to define levels of stability and instability for each elevation-change value (1,525,339 data points at 2-m horizontal resolution) based on the amount of erosion and accretion during the 2017 to 2018 time period. Seafloor-stability point and triangulated irregular network (TIN) surface models were created at five different elevation-change data resolutions (1st order through 5th order) with each resolution becoming increasingly more detailed. The stability point models were used to determine the level of seafloor stability at seven habitat types found at Crocker Reef. This data release includes ArcGIS map packages containing the binned and color-coded stability point and surface (TIN) models and habitat files; maps of each stability model; and data tables containing stability and elevation-change data for the habitat types. Data were collected under Florida Keys National Marine Sanctuary permit FKNMS-2016-068.

美国地质调查局（U.S. Geological Survey, USGS）圣彼得堡海岸与海洋科学中心（St. Petersburg Coastal and Marine Science Center, SPCMSC）开展了一项研究，旨在通过分析佛罗里达州伊斯兰洛拉达附近克罗克礁2017至2018年的海底高程变化，识别该区域的海底高程稳定与不稳定区域，研究覆盖面积达6.11平方千米。USGS SPCMSC的研究人员采用了Yates等人（2019）发布的海底高程变化数据集，该数据集通过采用Yates等人（2017）的分析方法，对2017年与2018年获取的两份原始高程数据集开展高程变化计算后得到。研究基于2017年与2018年数字高程模型（Digital Elevation Model, DEMs）的垂直不确定性，为2017-2018年克罗克礁高程变化数据集确定了海底稳定性阈值。研究构建了5级稳定性分类体系，具体分级标准如下：稳定级：0.0米（m）至±0.24米，或0.0米至±0.49米；中等稳定级：±0.25米至±0.49米；中等不稳定级：±0.50米至±0.74米；大部不稳定级：±0.75米至±0.99米；完全不稳定级：±1.00米至最大/最小高程变化值。该体系用于依据2017至2018年的侵蚀与淤积量，对每个高程变化值（水平分辨率为2米，共计1,525,339个数据点）的稳定与不稳定等级进行界定。研究人员以5种不同的高程变化数据分辨率（1阶至5阶）构建了海底稳定性点模型与不规则三角网（Triangulated Irregular Network, TIN）表面模型，各分辨率的模型细节程度依次提升。该稳定性点模型被用于分析克罗克礁内7类生境类型的海底稳定性等级。本数据集发布内容包含：已分箱并配色的稳定性点模型、表面（TIN）模型与生境文件对应的ArcGIS地图包；各稳定性模型的专题地图；以及包含生境类型稳定性与高程变化数据的数据表。本数据采集工作获得佛罗里达礁岛群国家海洋保护区许可FKNMS-2016-068。