Collaborative Research: Physical Drivers of Equivalent Temperature Variability

该研究项目将量化美国东部等效温度的历史和预测未来变化。 等效温度是一个考虑近地面空气总能量含量的指标，同时考虑干（感热）和湿（潜热）分量。 因此，它与人体热应激很好地吻合，当温度和湿度同时升高时，热应激会增加。 由于等效温度对温度和湿度的变化都很敏感，因此等效温度的变化可以反映从全球到区域范围内发生的处理。 该项目的目标是诊断等效温度的历史变化并将其归因于区域范围内发生的过程（例如土壤湿度异常导致的湿度变化），天气尺度（例如与大气环流变化相关的温度和湿度变化），和全球尺度（例如与温室气体辐射强迫变化有关的温度和湿度变化）。 该项目将在编制21世纪等效温度预测的范围内，在大气-海洋环流耦合模型和区域气候模型内调查这些过程，该项目将满足国家气候评估进程中确定的研究需要：更好地了解大气对大气成分变化的反应，并更好地了解可能威胁人类健康和福祉的大气变化。 等效的温度变化以前没有被认为是在多个尺度的影响。 将等效温度的变化归因于它们作用的空间尺度上的基本过程，将允许探索历史记录中等效温度趋势的机械理解。 利用统计和动力学方法并结合驱动过程的知识，缩小大气和海洋环流模型的尺度，将使研究人员能够对未来等效温度输出进行现有的最佳预测，并将这些预测置于对历史变化驱动因素的严格理解的背景下。 该项目的结果将对气候变化适应和规划产生广泛影响，因为等效温度及其组成部分的变化可能对本世纪的人类健康和农业至关重要。 项目结果将在机构存档，并提供给研究界。 该项目为每个机构的多名研究生提供支持，从而有助于下一代地理学家和大气科学家的发展。

This research project will quantify historical and projected future variability in equivalent temperature in the eastern United States. Equivalent temperature is a metric that considers the total energy content of near-surface air by accounting for both the dry (sensible heat) and moist (latent heat) components. It therefore aligns well with human heat stress, which increases when temperature and humidity are simultaneously elevated. Because equivalent temperature is sensitive to changes in both temperature and humidity, variations in equivalent temperature can reflect processing occurring across a range of scales from global to regional. The objective of this project is to diagnose and attribute historical changes in equivalent temperature to processes occurring at the regional scale (e.g. changes in humidity resulting from soil moisture anomalies), the synoptic scale (e.g. changes in temperature and humidity associated with changes in the atmospheric circulation), and the global scale (e.g. changes in temperature and humidity associated with changes in radiative forcing from greenhouse gases). The project will investigate these processes within coupled atmosphere ocean general circulation models and regional climate models in the context of developing 21st-century equivalent temperature projections.This project will address research needs identified in the National Climate Assessment process: to better understand atmospheric responses to atmospheric composition change and to improve understanding of atmospheric changes that may threaten human health and well-being. Equivalent temperature variability has not been previously considered in terms of multiple scales of influence. Attributing variations in equivalent temperature to the underlying processes across the spatial scales at which they act will allow exploration of mechanistic understanding of equivalent temperature tendencies in the historical record. Downscaling atmosphere ocean general circulation models using statistical and dynamical approaches with knowledge of the driving processes will allow the researchers to develop the best available projections of future equivalent temperature output and to contextualize those projections within a rigorous understanding of drivers of historical change. The results of the project will have broad implications for climate change adaptation and planning, because changes in equivalent temperature and its components may be critical for both human health and agriculture this century. Project results will be institutionally archived and made available to the research community. The project provides support for multiple graduate students at each institution, and thus contributes to development of the next generation of geographers and atmospheric scientists.