Livneh Historical Observations Cold Days

The Climate Resilience Information System (CRIS) provides data and tools for developers of climate services. This layer has historical variables in decadal increments from 1950 to 2020 derived from historical observations of air temperature and precipitation. 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 Livneh gridded precipitation and other meteorological variables for continental US, Mexico and southern Canada. Further processing by Esri is explained below. For each variable, there are mean values for the defined respective geography: counties, tribal areas, HUC-8 watersheds. The process for deriving these summaries is available from the CRIS Website’s About the Data. Other climate variables are available from the CRIS Data page. Additional geographies, including Alaska, Hawai’i and Puerto Rico will be made available in the future. Geographies This layer provides historic 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 Historic climate threshold values (e.g. Days Over 90°F) were calculated for each year from 1950 to 2020. To ensure the layer displays time correctly, under 'Map properties' set Time zone to 'Universal Coordinated Time (UTC)' and under 'Time slider options' set Time intervals to '1 Decade'. Data Citation Livneh, B., T. J. Bohn, D. W. Pierce, F. Munoz-Arriola, B. Nijssen, R. Vose, D. R. Cayan, and L. Brekke, 2015: A spatially comprehensive, hydrometeorological data set for Mexico, the U.S., and Southern Canada 1950 - 2013. Scientific Data, 2, https://doi.org/10.1038/sdata.2015.42. Data Export Exporting this data into shapefiles, geodatabases, GeoJSON, etc is enabled.气候韧性信息系统（Climate Resilience Information System, CRIS）为气候服务开发者提供数据与工具。本图层包含1950年至2020年间以十年为间隔的历史变量，此类数据源自气温与降水的历史观测记录。所涵盖的变量如下： 1. 最低气温≤0°F的年度累计天数 2. 最低气温≤28°F的年度累计天数 3. 最低气温≤32°F的年度累计天数 4. 最高气温≤32°F的年度累计天数 本图层采用针对美国本土、墨西哥与加拿大南部的Livneh网格化降水及其他气象变量数据集。Esri后续开展的处理流程详见下文。针对每一类变量，本图层均提供对应地理分区的平均值，涵盖县、部落领地与HUC-8流域。此类汇总数据的生成方法可于CRIS官网的“数据概况”板块查询。更多气候变量可在CRIS数据页面获取。未来还将推出包含阿拉斯加、夏威夷与波多黎各在内的更多地理分区数据集。 ### 地理分区 本图层为三类地理分区提供历史数值：县、部落领地与HUC-8流域。 - 县：基于美国人口普查局（U.S. Census）TIGER/Line 2022版发布数据。 - 部落领地：基于美国人口普查局2022版发布的《美国印第安人/阿拉斯加原住民/夏威夷原住民领地数据集》（American Indian/Alaska Native/Native Hawaiian Area dataset），该数据集涵盖联邦与州认定的统计区域。 - HUC-8流域：基于美国地质调查局（United States Geological Survey, USGS）清洗后的边界数据集（Washed Boundary Dataset），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 本数据集针对1950年至2020年的每一年计算了气候阈值历史数值（例如“高温天数超过90°F”）。为确保图层正确显示时间，请在“地图属性”中将时区设置为“协调世界时（Universal Coordinated Time, UTC）”，并在“时间滑块选项”中将时间间隔设置为“1十年”。 ### 数据引用 Livneh, B., T. J. Bohn, D. W. Pierce, F. Munoz-Arriola, B. Nijssen, R. Vose, D. R. Cayan, and L. Brekke, 2015: A spatially comprehensive, hydrometeorological data set for Mexico, the U.S., and Southern Canada 1950 - 2013. *Scientific Data*, 2, https://doi.org/10.1038/sdata.2015.42. ### 数据导出 本数据集支持导出为Shapefile、地理数据库（geodatabase）、GeoJSON等格式。