Sea-Level Rise Visualizations Based on Projection Data from the NOAA 2022 Report

This Geographic Information System (GIS) dataset is part of a comprehensive effort designed to facilitate analysis and understanding of sea-level-rise exposure in the United States and outlying territories. The dataset is derived from sea-level-rise projections published in two National Oceanic and Atmospheric Administration (NOAA) technical reports: 1) Global and Regional Sea Level Rise Scenarios for the United States (2017; https://tidesandcurrents.noaa.gov/publications/techrpt83_Global_and_Regional_SLR_Scenarios_for_the_US_final.pdf) and 2) Global and Regional Sea Level Rise Scenarios for the United States: Updated Mean projections and Extreme Water Level Probabilities Along U.S. Coastlines (2022; https://sealevel.globalchange.gov/internal_resources/756/noaa-nos-techrpt01-global-regional-SLR-scenarios-US.pdf). Each of the NOAA technical reports includes multiple sets of point projections based on mean global sea-level-rise scenarios. Global mean sea-level-rise scenarios provide an overall estimate of how sea level could change in the future. However, local effects can produce sea level changes that are substantially different than the global average. To capture those effects, the sea-level-rise projections produced for these reports utilized a 1-degree grid (approximately 111 km by 89 km at 38° north latitude) covering the coastlines of the U.S. mainland, Alaska, Hawaii, and the Caribbean and Pacific Island territories as well as the precise location of tide gauges along these coastlines. Adjustments to sea level projections at each point location include 1) shifts in oceanographic factors such as circulation patterns, 2) changes in the Earth’s gravitational field and rotation, and flexure of the crust and upper mantle, due to melting of land-based ice, 3) vertical land movement (subsidence or uplift) due to glacial isostatic adjustment (ongoing changes in elevation due to the retreat of ice sheets at the end of the last Ice Age), sediment compaction, groundwater and fossil fuel withdrawals and other non-climatic factors. The 2017 report included six scenarios: 0.3, 0.5, 1.0, 1.5, 2.0 and 2.5 meters of global mean sea-level rise; the 2022 report reassessed the projections for the first five scenarios and eliminated the extreme (2.5-m) scenario from consideration based on its very low probability of occurrence. The projections in these reports are provided at approximately decadal time scales and include a year 2000 baseline and the following time horizons: 2010 (2017 dataset only), 2020, 2030, 2040, 2050, 2060, 2070, 2080, 2090, 2100, 2110 (2022 dataset only), 2120, 2130 (2022 dataset only), 2140 (2022 dataset only), 2150, and 2200 (2017 dataset only). GIS visualizations for each of these 149 combinations is available as polygons that show areal extent of mean sea level and rasters that include a water depth component for each pixel at 30-m resolution. Data files are grouped by dataset (2017 or 2022) and geography, with the continental United States divided along regional boundaries used by the US Environmental protection Agency. These datasets are intended to provide users with GIS data layers linked to time horizons that are useful to programmatic or project-based planning processes, thus providing critical insight for policymakers, researchers, planners, and others concerned with climate adaptation practices addressing sea-level rise in coastal areas.本地理信息系统（Geographic Information System, GIS）数据集隶属于一项系统性研究项目，旨在助力美国及其海外领地海平面上升暴露情况的分析与认知。本数据集源自美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）两份技术报告中发布的海平面上升预测数据：1）《美国全球及区域海平面上升情景》（2017年；https://tidesandcurrents.noaa.gov/publications/techrpt83_Global_and_Regional_SLR_Scenarios_for_the_US_final.pdf）；2）《美国全球及区域海平面上升情景：美国沿海地区平均预测更新与极端水位概率》（2022年；https://sealevel.globalchange.gov/internal_resources/756/noaa-nos-techrpt01-global-regional-SLR-scenarios-US.pdf）。 两份美国国家海洋和大气管理局技术报告均包含多组基于全球平均海平面上升情景的点位预测数据。全球平均海平面上升情景可对未来海平面变化做出整体预估，但局地效应会导致实际海平面变化与全球平均值出现显著差异。为还原此类局地效应，两份报告中的海平面上升预测采用了覆盖美国本土、阿拉斯加、夏威夷、加勒比及太平洋岛屿领地海岸线的1度网格（北纬38°处约为111千米×89千米），同时纳入了上述沿海地区验潮站的精确位置。各点位的海平面上升预测修正项包含三类：1）海洋环流模式等海洋学要素的变化；2）由陆地冰融化引发的地球重力场与自转变化，以及地壳和上地幔的挠曲形变；3）由冰川均衡调整（末次冰期结束后冰盖消退导致的持续高程变化）、沉积物压实、地下水与化石燃料开采及其他非气候因素引发的垂直陆地运动（沉降或抬升）。 2017年报告共包含6种情景：全球平均海平面上升0.3、0.5、1.0、1.5、2.0及2.5米；2022年报告对前5种情景的预测进行了重新评估，并基于2.5米情景发生概率极低的考量将其剔除。两份报告中的预测以约十年为时间步长，以2000年为基准年，时间节点涵盖：2010年（仅2017年数据集包含）、2020年、2030年、2040年、2050年、2060年、2070年、2080年、2090年、2100年、2110年（仅2022年数据集包含）、2120年、2130年（仅2022年数据集包含）、2140年（仅2022年数据集包含）、2150年及2200年（仅2017年数据集包含）。针对上述149种情景-时间节点组合，可获取两类地理信息系统可视化成果：用于展示平均海平面影响范围的多边形数据，以及包含30米分辨率像素水深信息的栅格数据。数据文件按数据集（2017年或2022年）与地理区域分组，其中美国本土按照美国环境保护署（United States Environmental Protection Agency, EPA）划定的区域边界进行分区。 本数据集旨在为用户提供与时间节点关联的地理信息系统数据图层，可服务于规划项目或专项工程的决策流程，从而为政策制定者、科研人员、规划师及其他关注沿海地区海平面上升气候适应举措的相关群体提供关键参考依据。