Climate Change Pressures Heat Zones Mean Days Over 30 Degrees Celsius RCP45 2040-2069

Evaluating multiple signals of climate change across the conterminous United States during three 30-year periods (2010�2039, 2040�2069, 2070�2099) during this century to a baseline period (1980�2009) emphasizes potential changes for growing degree days (GDD), plant hardiness zones (PHZ), and heat zones. These indices were derived using the CCSM4 and GFDL CM3 models under the representative concentration pathways 4.5 and 8.5, respectively, and included in Matthews et al. (2018). Daily temperature was downscaled by Maurer et al. (https://doi.org/10.1029/2007EO470006) at a 1/8 degree grid scale and used to obtain growing degree days, plant hardiness zones, and heat zones. Each of these indices provides unique information about plant health related to changes in climatic conditions that influence establishment, growth, and survival. These data and the calculated changes are provided as 14 individual IMG files for each index to assist with management planning and decision making into the future. For each of the four indices the following are included: two baseline files (1980�2009), three files representing 30-year periods for the scenario CCSM4 under RCP 4.5 along with three files of changes, and three files representing 30-year periods for the scenario GFDL CM3 under RCP 8.5 along with three files of changes.Heat zones map the distribution of potential heat stress for plants and animals, including humans. We define heat zones as the number of days with maximum daily temperature >30 �C (86 �F). Because species have unique adaptations and abilities to tolerate a wide variety of conditions, this metric is used merely as an indicator of change in �hot� conditions. The 30 �C value is set primarily for agricultural production and is a general temperature threshold at which photosynthesis can be negatively impacted for C3 plants (e.g., most species including trees), but it certainly also captures temperatures that induce stress in humans as well. In addition, increases in temperature above these thresholds for longer periods, especially when accompanied with prolonged dry conditions, are linked to reduced performance and likely mortality of trees. Each day surpassing the 30 �C threshold was tallied and summed for each year and reported as the mean number of days, per year, over each 30-year period: baseline, early, mid, and late century.�Original data and associated metadata can be downloaded from this website:�https://www.fs.usda.gov/rds/archive/Product/RDS-2019-0001This record was taken from the USDA Enterprise Data Inventory that feeds into the https://data.gov catalog. Data for this record includes the following resources: ISO-19139 metadata ArcGIS Hub Dataset ArcGIS GeoService For complete information, please visit https://data.gov.

本世纪内，针对美国大陆地区三个30年时段（2010-2039年、2040-2069年、2070-2099年）以及基准时段（1980-2009年）的气候变化多种信号进行评估，着重分析潜在的生长度日（GDD）、植物耐寒区（PHZ）和高温区等指标的变化。这些指标系采用CCSM4和GFDL CM3模型，分别在代表浓度路径4.5和8.5下进行计算得出，并被收录于Matthews等人的著作（2018年）。每日气温数据经Maurer等人（https://doi.org/10.1029/2007EO470006）以1/8度网格尺度进行降尺度处理，并据此计算生长度日、植物耐寒区和高温区。这些指标各自提供了关于植物健康与气候变化影响（如植物建立、生长和存活）相关的独特信息。这些数据和计算出的变化以每个指标14个单独的IMG文件的形式提供，以辅助未来管理规划和决策制定。对于四个指标中的每一个，均包含以下内容：两个基准文件（1980-2009年）、代表CCSM4模型在RCP 4.5情景下的30年时段文件及其变化文件各三个，以及代表GFDL CM3模型在RCP 8.5情景下的30年时段文件及其变化文件各三个。高温区映射植物和动物（包括人类）潜在的热应激分布。我们定义高温区为每日最高气温超过30°C（86°F）的天数。由于物种具有独特的适应性和耐受各种条件的能力，此指标仅用作“高温”条件变化的指示器。30°C的数值主要针对农业生产设定，是光合作用可能受到负面影响的一般温度阈值，尤其是对于C3植物（如大多数物种，包括树木），但无疑也涵盖了引起人类热应激的温度。此外，超过这些阈值的温度在较长时间内上升，尤其是在伴随长期干旱条件下，与树木性能下降和可能死亡有关。对于每年超过30°C阈值的天数进行累计，并报告为每个30年时段（基准期、早期、中期和晚期）每年的平均天数。原始数据和关联元数据可从本网站下载：https://www.fs.usda.gov/rds/archive/Product/RDS-2019-0001。此记录来源于USDA企业数据目录，该目录输入至https://data.gov目录。此记录的数据包括以下资源：ISO-19139元数据、ArcGIS Hub数据集、ArcGIS GeoService。欲获取完整信息，请访问https://data.gov。