Abstract
The hydroclimatology of the southeastern U.S. is changing, with increased precipitation, intensified summer-to-fall rainfall, and prolonged dry periods. However, research has yet to determine whether these trends are present in the southern Appalachian Mountains, which contain the most topographic and hydroclimatic variability across the region and serve as a valuable resource for growing population centers. This study examines warm season hydroclimatic variability and changes from 1950 to 2018 using the Global Historical Climatological Network (GHCN) daily data record. Daily rainfall is classified according to different intensities, ranging from light to heavy, and a Mann-Kendall test is used to determine the trend at each station. Additionally, a Spearman’s rank correlation test is performed to test for significant linkages between precipitation class frequencies and large-scale modes of atmospheric variability (Atlantic Multidecadal Oscillation, Caribbean SST Index, Pacific/North American Pattern). The results suggest that dry days became less common and light precipitation became more common across the southern Appalachian region. Similarly, the length of dry spells became shorter at most elevations. Teleconnection patterns are linked to the variability of precipitation class frequencies, particularly with dry days and light precipitation. In conclusion, this research reveals the unique character of hydroclimatic variability and change across the southern Appalachian region in the context of the broader southeastern U.S.
Highlights
The hydroclimatology of mountain regions remains poorly understood, yet it is directly tied to regional water resources, ecosystem services, and the development of water-related natural hazards.While much research has examined the impacts of precipitation extremes, ranging from droughts to floods, putting these events into context with hydroclimatic variability and change remains a challenge [1,2,3,4,5]
These results suggest that the hydroclimate of the Southern Appalachian Mountains (SAM) became slightly wetter over the time period, with fewer individual dry days occurring during the warm season
Hydroclimate extremes documented in other studies do affect the SAM, we suggest that the near-daily occurrence of showers and thundershowers from convection on mountain slopes influence the change to the light precipitation regime identified in this study
Summary
The hydroclimatology of mountain regions remains poorly understood, yet it is directly tied to regional water resources, ecosystem services, and the development of water-related natural hazards.While much research has examined the impacts of precipitation extremes, ranging from droughts to floods, putting these events into context with hydroclimatic variability and change remains a challenge [1,2,3,4,5]. The hydroclimatology of mountain regions remains poorly understood, yet it is directly tied to regional water resources, ecosystem services, and the development of water-related natural hazards. The hydroclimate is challenging to study because there are many atmospheric variables, such as humidity, cloud cover, atmospheric pressure, instability, and moisture contributing, which complicates crafting comprehensive generalizations. This is especially true in mountainous regions, where the complexity of terrain-atmospheric interactions is not understood [6]. Provoking these challenges is the lack of long and high temporal coverage climate data in mountainous regions. Weather stations are sparse in the Southern Appalachian Mountains (SAM) region; this limits climate model development and trend detection in this diverse environment [7,8]
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