Climate Change Pressures Heat Zones Mean Days Over 30 Degrees Celsius RCP45 2070-2099 (Image Service)

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，对整个美国大陆在三个30年期间（2010-2039年、2040-2069年、2070-2099年）的气候变化多项指标进行评估，并与基线期（1980-2009年）进行对比，着重强调了生长度日（GDD）、植物耐寒区（PHZ）和高温区等潜在变化。这些指数分别采用CCSM4和GFDL CM3模型，在代表性浓度路径4.5和8.5下生成，并由Matthews等人（2018年）收录。每日气温通过Maurer等人（https://doi.org/10.1029/2007EO470006）的方法在1/8度网格尺度上进行降尺度处理，并据此计算出生长度日、植物耐寒区和高温区。这些指数各自提供了关于植物健康与气候变化影响（如植物生长、生存等）的独特信息。这些数据和计算出的变化以14个独立的IMG文件的形式，针对每个指数分别提供，以协助未来的管理规划和决策制定。对于四个指数中的每一个，都包括以下内容：两个基线文件（1980-2009年）、代表CCSM4模型在RCP 4.5情景下的30年期间的三份文件以及相应的三份变化文件，以及代表GFDL CM3模型在RCP 8.5情景下的30年期间的三份文件及其变化文件。高温区映射了植物和动物（包括人类）潜在的热应激分布。我们将高温区定义为每日最高气温超过30°C（86°F）的天数。鉴于物种具有独特的适应性和耐受各种条件的能力，这一指标仅作为“热”条件变化的指示器。30°C的阈值主要针对农业生产，是一般温度阈值，在此温度下，C3植物（如大多数树种）的光合作用可能受到负面影响，但这一值显然也捕捉到了对人类造成压力的温度。此外，在超过这些阈值的温度下，长时间的升高，尤其是伴随持续的干旱条件，与树木性能下降以及可能导致的死亡率增加有关。对于每年超过30°C阈值的天数进行计数和汇总，并报告为每个30年期间（基线、早期、中期和晚期）每年平均天数。原始数据和相关的元数据可从以下网站下载：https://www.fs.usda.gov/rds/archive/Product/RDS-2019-0001。本记录源自美国农业部企业数据目录，该目录输入到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。