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Freezing Temperature Controls Winter Water Discharge for Cold Region Watershed.

Authors :
Wang, Shusen
Source :
Water Resources Research; Dec2019, Vol. 55 Issue 12, p10479-10493, 15p
Publication Year :
2019

Abstract

Pronounced climate warming over the arctic‐subarctic regions has lead to profound hydrological changes including intensified river flow, but how soil frost controls aquifer discharge remains poorly understood. This study quantifies the relationship between freezing temperature and baseflow in winter. Analyses show that the traditional reservoir models are unable to reproduce the observed baseflow variations. By incorporating a freezing temperature function in the reservoir models, the model performances are largely improved. It indicates the dominant role of freezing temperature in controlling the aquifer discharge through reducing the watershed conductivity and liquid (active) water content. The results for the Albany watershed in Canada show that the watershed lump conductivity decreases by half when air temperature accumulates to −172 °C·day from winter start and in extremely cold years, it could decrease by more than 85%. With this relationship, a climate warming of +1, +2, and +4 °C would suggest an increase of 7.7%, 16.7%, and 41.0% in conductivity or 6.8%, 14.7%, and 35.0% in winter discharge, respectively. The study provides an important link between climate warming and aquifer discharge in cold regions. The results could be particularly useful for developing process‐based models, estimating baseflow variations, and assessing climate change impact on cold region hydrology. Plain Language Summary: Pronounced climate warming over the arctic‐subarctic regions has lead to intensified river flow, but how soil frost controls aquifer discharge remains poorly understood. This study reveals the relationship between freezing temperature and baseflow in winter. The results show that freezing temperature reduces baseflow through decreasing hydraulic conductivity by more than 85% in extremely cold years for the Albany watershed in Canada. As such, a climate warming of +1, +2, and +4 °C could result in an increase in winter aquifer discharge of 6.8%, 14.7%, and 35.0%, respectively. The temperature‐baseflow relationship found in this study provides new insight for cold region climate change impact and water resources studies. Key Points: Freezing temperature is the dominant factor controlling cold region winter baseflowSoil frost reduces baseflow by reducing hydraulic conductivity and active water contentClimate warming could significantly increase winter river flow in cold regions [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00431397
Volume :
55
Issue :
12
Database :
Complementary Index
Journal :
Water Resources Research
Publication Type :
Academic Journal
Accession number :
141436648
Full Text :
https://doi.org/10.1029/2019WR026030