The Impact of Shifts in Both Precipitation Pattern and Temperature Changes on River Discharge in Central Japan

Rivers play a crucial role in the hydrological cycle and serve as essential freshwater resources for both human populations and ecosystems. Climate change significantly alters precipitation patterns and river discharge variability. However, the impact of precipitation patterns (rainfall and snowfall...

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Main Authors: Bing Zhang, Jingyan Han, Jianbo Liu, Yong Zhao
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Hydrology
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Online Access:https://www.mdpi.com/2306-5338/12/7/187
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author Bing Zhang
Jingyan Han
Jianbo Liu
Yong Zhao
author_facet Bing Zhang
Jingyan Han
Jianbo Liu
Yong Zhao
author_sort Bing Zhang
collection DOAJ
description Rivers play a crucial role in the hydrological cycle and serve as essential freshwater resources for both human populations and ecosystems. Climate change significantly alters precipitation patterns and river discharge variability. However, the impact of precipitation patterns (rainfall and snowfall) and air temperature on river discharge in coastal zones remains inadequately understood. This study focused on Toyama Prefecture, located along the Sea of Japan, as a representative coastal area. We analyzed over 30 years of datasets, including air temperature, precipitation, snowfall, and river discharge, to assess the effects of climate change on river discharge. Trends in hydroclimatic datasets were assessed using the rescaled adjusted partial sums (RAPS) method and the Mann–Kendall (MK) non-parametric test. Furthermore, a correlation analysis and the Structural Equation Model (SEM) were applied to construct a relationship between precipitation, temperature, and river discharge. Our findings indicated a significant increase in air temperature at a rate of 0.2 °C per decade, with notable warming observed in late winter (January and February) and early spring (March). The average river fluxes for the Jinzu, Oyabe, Kurobe, Shou, and Joganji rivers were 182.52 m<sup>3</sup>/s, 60.37 m<sup>3</sup>/s, 41.40 m<sup>3</sup>/s, 38.33 m<sup>3</sup>/s, and 18.72 m<sup>3</sup>/s, respectively. The tipping point for snowfall decline occurred in 1992, marked by an obvious decrease in snowfall depth. The SEM showed that, although rainfall dominated the changes in river discharge (loading = 0.94), the transition from solid (snow) to liquid (rain) precipitation may alter the river discharge regime. The percentage of flood occurrence increased from 19% (1940–1992) to 41% (1993–2020). These changes highlight the urgent need to raise awareness about the impacts of climate change on river floods and freshwater resources in global coastal regions.
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spelling doaj-art-b8b5853ca128432a8af820aea66477512025-08-20T03:32:32ZengMDPI AGHydrology2306-53382025-07-0112718710.3390/hydrology12070187The Impact of Shifts in Both Precipitation Pattern and Temperature Changes on River Discharge in Central JapanBing Zhang0Jingyan Han1Jianbo Liu2Yong Zhao3Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin 300387, ChinaCollege of Water Conservancy Engineering, Tianjin Agricultural University, Tianjin 300392, ChinaTianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin 300387, ChinaState Key Laboratory of Water Cycle and Water Sercurity, China Institute of Water Resources and Hydropower Research, Beijing 100038, ChinaRivers play a crucial role in the hydrological cycle and serve as essential freshwater resources for both human populations and ecosystems. Climate change significantly alters precipitation patterns and river discharge variability. However, the impact of precipitation patterns (rainfall and snowfall) and air temperature on river discharge in coastal zones remains inadequately understood. This study focused on Toyama Prefecture, located along the Sea of Japan, as a representative coastal area. We analyzed over 30 years of datasets, including air temperature, precipitation, snowfall, and river discharge, to assess the effects of climate change on river discharge. Trends in hydroclimatic datasets were assessed using the rescaled adjusted partial sums (RAPS) method and the Mann–Kendall (MK) non-parametric test. Furthermore, a correlation analysis and the Structural Equation Model (SEM) were applied to construct a relationship between precipitation, temperature, and river discharge. Our findings indicated a significant increase in air temperature at a rate of 0.2 °C per decade, with notable warming observed in late winter (January and February) and early spring (March). The average river fluxes for the Jinzu, Oyabe, Kurobe, Shou, and Joganji rivers were 182.52 m<sup>3</sup>/s, 60.37 m<sup>3</sup>/s, 41.40 m<sup>3</sup>/s, 38.33 m<sup>3</sup>/s, and 18.72 m<sup>3</sup>/s, respectively. The tipping point for snowfall decline occurred in 1992, marked by an obvious decrease in snowfall depth. The SEM showed that, although rainfall dominated the changes in river discharge (loading = 0.94), the transition from solid (snow) to liquid (rain) precipitation may alter the river discharge regime. The percentage of flood occurrence increased from 19% (1940–1992) to 41% (1993–2020). These changes highlight the urgent need to raise awareness about the impacts of climate change on river floods and freshwater resources in global coastal regions.https://www.mdpi.com/2306-5338/12/7/187precipitationair temperaturesnowfallriver dischargeToyamaJapan
spellingShingle Bing Zhang
Jingyan Han
Jianbo Liu
Yong Zhao
The Impact of Shifts in Both Precipitation Pattern and Temperature Changes on River Discharge in Central Japan
Hydrology
precipitation
air temperature
snowfall
river discharge
Toyama
Japan
title The Impact of Shifts in Both Precipitation Pattern and Temperature Changes on River Discharge in Central Japan
title_full The Impact of Shifts in Both Precipitation Pattern and Temperature Changes on River Discharge in Central Japan
title_fullStr The Impact of Shifts in Both Precipitation Pattern and Temperature Changes on River Discharge in Central Japan
title_full_unstemmed The Impact of Shifts in Both Precipitation Pattern and Temperature Changes on River Discharge in Central Japan
title_short The Impact of Shifts in Both Precipitation Pattern and Temperature Changes on River Discharge in Central Japan
title_sort impact of shifts in both precipitation pattern and temperature changes on river discharge in central japan
topic precipitation
air temperature
snowfall
river discharge
Toyama
Japan
url https://www.mdpi.com/2306-5338/12/7/187
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