Spatiotemporal Changes in Comfortable Weather Duration in the Continental United States and Implications for Human Wellness

Abstract

We examined the spatial distribution of monthly, seasonal, and annual changes in comfortable weather hours (CWHs) between 1950 and 2011 and explored the relationship between human wellness and the amount and timing of CWHs. Using a thermohygrometric index based on air temperature and dewpoint temperature recorded every three hours from thirty-five U.S. cities, we determined whether changes in human thermal comfort were coincident with warming and more humid atmospheric conditions. We tested for significant trends in CWHs for every season for each city for nighttime, daytime, and total (i.e., night and day) periods. Although approximately 75 percent of the cities did not experience significant changes in CWHs on an annual basis, total changes in CWHs were marked by increases during spring and decreases in summer conditions, with the largest positive changes in CWHs found during spring nights, spring days, and autumn nights and the largest negative changes during summer nights and days. Spatially, increases in CWHs were principally located west of 117°W and decreases in cities east of 81°W. Significant relationships existed between wellness metrics and seasonal and annual CWHs. Greater CWHs during the summer were positively correlated with happiness and well-being and negatively correlated with obesity. These results suggest that further declines in summer CWHs for cities might affect human wellness, as peak optimal weather conditions shift toward spring and autumn months.

我们检视 1950 年至 2011 年间, 舒适气候时间（CWHs）的月、季和年度变迁之空间分佈, 并探讨人类健康和 CWHs 总量与时间之间的关係。我们运用在美国三十五座城市中, 每三小时记录的根据空气温度和露点温度的热比重指标, 判定人类温暖舒适度的改变, 是否与变暖和更为潮溼的大气条件相符合。我们检测每个城市在每一季的晚上、白天和总时程（例如日夜）的 CWHs 的显着趋势。儘管大约百分之七十五的城市并未经历以年度为基准的 CWHs 的显着改变, 但 CWHs 的总改变量则在春天增加, 在夏天的情境中则减少, 而 CWHs 最大幅的正向改变, 则在春天晚上、春天白天和秋天晚上发现, 最大的降幅改变, 则是在夏日的晚上和白天发现。在空间上, CWHs 的增加, 主要落在西经 117 度以西, 而在西经 81 度以东的城市中减少。 健康度量和季度与年度 CWHs 之间存在着显着关係。夏季更大的 CWHs, 与快乐和健康具有正相关, 而与肥胖具有负相关。这些结果指出, 当最高的理想气候条件转向春天和秋天的月份时, 未来城市中夏季 CWHs 的减少, 可能会对人类健康造成影响。

Examinamos la distribución espacial de cambios mensuales, estacionales y anuales de las horas de tiempo agradable (CWHs) entre 1950 y 2011 y exploramos la relación entre bienestar humano y el número y horario de ocurrencia de las CWHs. Usando un índice termohigrométrico basado en temperatura del aire y en temperatura del punto de condensación registradas cada tres horas en treinta y cinco ciudades de los EE.UU., determinamos si los cambios en la comodidad térmica humana eran coincidentes con el calentamiento y condiciones atmosféricas más húmedas. Hicimos pruebas para establecer tendencias significativas en las CWHs en cada estación para cada ciudad en los períodos nocturno, diurno y para el total (es decir, noche y día). Aunque aproximadamente el 75 por ciento de las ciudades no experimentaron cambios significativos de las CWHs en una base anual, los cambios en el total de las CWHs estuvieron marcados con incrementos durante la primavera y mermas en las condiciones veraniegas, con los cambios positivos más grandes de las CWHs registrados durante las noches de primavera, los días de la primavera y las noches de otoño, y los cambios negativos más grandes durante las noches y días del verano. Desde el punto de vista espacial, los incrementos de las CWHs se localizaron principalmente al occidente del meridiano 117°W, y las mermas en las ciudades situadas al oriente de 81°W. Se detectaron relaciones significativas entre las medidas de bienestar y las CWHs estacional y anual. Los mayores valores de la CWHs durante el verano estuvieron positivamente correlacionadas con los valores de felicidad y bienestar, y negativamente correlacionadas con la obesidad. Estos resultados sugieren que mayores mermas en las CWHs en las ciudades en verano podrían afectar el bienestar humano, a medida que el pico de las condiciones óptimas del tiempo se desplaza hacia los meses de primavera y otoño.

Key Words:

• climate change
• human thermal comfort
• U.S. cities
• wellness

关键词：:

• 气候变迁
• 人类温暖舒适度
• 美国城市
• 健康。

Palabras clave:

• cambio climático
• comodidad térmica humana
• ciudades de los EE.UU
• bienestar

Acknowledgments

We thank the three anonymous reviewers and the editor for their insightful comments and suggestions that helped significantly improve this article.

Supplemental Material

Supplemental data for this article can be accessed on the publisher's website at: http://dx.doi.org/10.1080/00045608.2015.1095058

Additional information

Notes on contributors

Paul A. Knapp

PAUL A. KNAPP is the Director of the Carolina Tree-Ring Science Laboratory and Professor in the Department of Geography at the University of North Carolina Greensboro, Greensboro, NC 27412. E-mail: [email protected]. His research interests include biogeography, climatology, and dendrochronology.

Justin T. Maxwell

JUSTIN T. MAXWELL is an Assistant Professor in the Department of Geography at Indiana University, Bloomington, IN 47405. E-mail: [email protected]. His research interests include examining climate variability, dendrochronology, and drought.

Jason T. Ortegren

JASON T. ORTEGREN is an Associate Professor in the Department of Earth and Environmental Sciences at the University of West Florida, Pensacola, FL 32514. E-mail: [email protected]. His research interests include hydroclimatology, freshwater resources, and North Atlantic climate variability.

Peter T. Soulé

PETER T. SOULÉ is a Professor in the Department of Geography and Planning at Appalachian State University in Boone, NC 28608. E-mail: [email protected]. His research interests are in climatology and dendroecology.