STAR-Ensemble SSP2-4.5 Cold Days

The Climate Resilience Information System (CRIS) provides data and tools for developers of climate services. This layer has projections of VAR in decadal increments from 1950 to 2100 and for three Shared Socioeconomic Pathways (SSPs). The variables included are: Annual number of days with a minimum temperature less than or equal to 0°F Annual number of days with a minimum temperature less than or equal to 28°F Annual number of days with a minimum temperature less than or equal to 32°F Annual number of days with a maximum temperature less than or equal to 32°F This layer uses data from the LOCA2 and STAR-ESDM downscaled climate models for the Contiguous United States. Further processing by the NOAA Technical Support Unit at CICS-NC and Esri are explained below. For each time and SSP, there are minimum, maximum, and mean values for the defined respective geography: counties, tribal areas, HUC-8 watersheds. The process for deriving these summaries is available in Understanding CRIS Data. The combination of time and geography is available for a weighted ensemble of 16 climate projections. More details on the models included in the ensemble and the weighting methodologies can be found in CRIS Data Preparation. Other climate variables are available from the CRIS website’s Data Gallery page or can be accessed in the table below. Additional geographies, including Alaska, Hawai’i and Puerto Rico will be made available in the future. Geographies This layer provides projected values for three geographies: county, tribal area, and HUC-8 watersheds. County: based on the U.S. Census TIGER/Line 2022 distribution. Tribal areas: based on the U.S. Census American Indian/Alaska Native/Native Hawaiian Area dataset 2022 distribution. This dataset includes federal- and state-recognized statistical areas. HUC-8 watershed: based on the USGS Washed Boundary Dataset, part of the National Hydrography Database Plus High Resolution. Time Ranges Projected climate threshold values (e.g. Days Over 90°F) were calculated for each year from 2005 to 2100. Additionally, values are available for the modeled history runs from 1951 - 2005. The modeled history and future projections have been merged into a single time series and averaged by decade. Climate Scenarios Climate models use future scenarios of greenhouse gas concentrations and human activities to project overall change. These different scenarios are called the Shared Socioeconomic Pathways (SSPs). Three different SSPs are available here: 2-4.5, 3-7.0, and 5-8.5 (STAR does not have SSP3-7.0). The number before the dash represents a societal behavior scenario. The number after the dash indicates the amount of radiative forcing (watts per meter square) associated with the greenhouse gas concentration scenario in the year 2100 (higher forcing = greater warming). It is unclear which scenario will be the most likely, but SSP 2-4.5 currently aligns with the international targets of the COP-26 agreement. SSP3-7.0 may be the most likely scenario based on current emission trends. SSP5-8.5 acts as a cautionary tale, providing a worst-case scenario if reductions in greenhouse gasses are not undertaken. Data Export Exporting this data into shapefiles, geodatabases, GeoJSON, etc is enabled.气候韧性信息系统（Climate Resilience Information System, 简称CRIS）为气候服务开发者提供数据与工具支持。本图层包含1950年至2100年以十年为间隔的VAR投影数据，以及三种共享社会经济路径（Shared Socioeconomic Pathways, 简称SSPs）下的对应数据。包含的变量如下：最低气温小于等于0华氏度的年度天数、最低气温小于等于28华氏度的年度天数、最低气温小于等于32华氏度的年度天数、最高气温小于等于32华氏度的年度天数。 本图层针对美国本土区域，采用LOCA2与STAR-ESDM降尺度气候模型的数据集。美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, 简称NOAA）下属CICS-NC技术支持单元及Esri公司所开展的进一步处理流程详见下文。 针对每个时间节点与SSP情景，已针对预设的三类地理单元（县、部落区域、HUC-8流域）计算得到最小值、最大值与平均值。此类汇总统计的推导流程可参阅《CRIS数据解读》（Understanding CRIS Data）文档。结合时间维度与地理单元的数据集基于16个气候投影模型的加权集成结果生成。关于集成模型选取与加权方法的更多细节，可参阅《CRIS数据制备》（CRIS Data Preparation）文档。 其他气候变量可通过CRIS官网的数据图库页面获取，或参阅下文附表。未来将新增包含阿拉斯加、夏威夷及波多黎各在内的更多地理单元数据。 ## 地理单元 本图层提供三类地理单元的投影数据：县、部落区域及HUC-8流域。 - 县界：基于美国人口普查局2022版TIGER/Line矢量数据集 - 部落区域：基于美国人口普查局2022版美国印第安人/阿拉斯加原住民/夏威夷原住民区域数据集，该数据集包含联邦及州政府认可的统计区域 - HUC-8流域：基于美国地质调查局（United States Geological Survey, 简称USGS）清洗边界数据集，该数据集隶属于国家水文数据库Plus高分辨率（National Hydrography Database Plus High Resolution）系列 ## 时间范围 气候阈值投影数据（如90华氏度以上天数）的计算时段为2005年至2100年的逐年数据；此外还包含1951年至2005年的历史模拟运行数据。历史模拟数据与未来投影数据已合并为单一时序序列，并按十年周期进行平均处理。 ## 气候情景 气候模型通过模拟温室气体浓度与人类活动的未来情景，预测气候整体变化，此类不同情景即称为共享社会经济路径（Shared Socioeconomic Pathways, 简称SSPs）。本次数据集提供三种SSP情景：2-4.5、3-7.0及5-8.5（STAR模型未包含SSP3-7.0情景）。 横杠前的数字代表社会行为情景类型，横杠后的数字则代表2100年时该温室气体浓度情景对应的辐射强迫量（单位：瓦/平方米），辐射强迫越高意味着气候变暖幅度越大。目前无法确定哪种情景最符合未来实际发展，但SSP2-4.5目前与第26届联合国气候变化大会（COP-26）达成的国际气候目标相符。基于当前排放趋势，SSP3-7.0或为最贴合实际的情景。SSP5-8.5则作为警戒情景，展示了若不采取温室气体减排措施将面临的最坏情况。 ## 数据导出 支持将本数据集导出为Shapefile、地理数据库（geodatabase）、GeoJSON等格式。