Impact of Climate Change on Drought in the Upstream Yangtze River Region

Abstract

Based on Coupled Model Intercomparison Project Phase 5 (CMIP5) dataset and a variable infiltration capacity (VIC) hydrological model, this study assesses the possible influence of climate change in the upstream region of the Yangtze River on droughts in the future 30 years. Long-term daily soil moisture content were simulated by VIC model at a 50 km × 50 km resolution from 1951 to 2013. Regional historical drought events were then recognized based on soil moisture anomaly percentage index and validated with field data. Five relatively independent representative global circulation models were selected and the outputs of them were downscaled temporally and spatially as the inputs of VIC model for daily soil moisture content simulations both in the period of 1971-2000 for the present-day climate and in the period of 2021-2050 for the future. The results show that the projected annual mean temperature is likely to increase from 1.4 • C to 1.8 • C. The projected change in mean annual precipitation could be increased slightly by 0.6% to 1.3%, but the trend of precipitation change in summer and autumn might be opposite of that. Comparing the drought characteristics values recognized in 1971-2000, seven to eight additional regional drought events are likely to happen in 2021-2050. Drought duration and drought intensity are also likely to extend for 18 d to 25 d and increase by 1.2% to 6.2%, respectively. But, drought area could decrease slightly by 1.3% to 2.7% on average. These changes in drought characteristics values suggest that regional drought could become more severely prolonged and frequent in future.

Projected Effects of Climate Change on Future Hydrological Regimes in the Upper Yangtze River Basin, China

“…is result is confirmed by the research of Lu et al [37], which states that the regional drought could become more severely prolonged and frequent in the future in this region according to the Soil Moisture Anomaly Percentage Index. Dai et al [2] and Birkinshaw et al [1] found that higher temperatures coupled with greater evapotranspiration will lead to a decrease in discharge and drought risks.…”

Water–Soil–Vegetation Dynamic Interactions in Changing Climate

“…The new algorithms presented in four articles [39,40,44,45,48] provide necessary tools for better modeling effects of grazing on steppe grassland degradation, future climates on sedimentation at watershed scale, micro-topographic features (e.g., puddles) on hydrologic processes, and infiltration on the translational stability of long slopes. In addition, two articles [41,43] found that human activities were the primary reason for runoff reduction, whereas, another article [42] showed that climate variability was the dominant driver for decreasing trend of streamflow. Such an apparent difference between these studies can be attributed to the fact that the basins of the former study areas (i.e., Yellow River and Yangtze River basins) are much more populated than watershed of the latter study area (i.e., upper Red River watershed).…”

“…The articles cover a wide range of geographic regions across China [39][40][41][42][43][44]46,47,49,50] and the United States of America (USA) [45,48] with contrasting hydro-climate, soil, and vegetation conditions. Thus, the results presented in these articles can have global inferences: the data, analysis/modeling approaches, results, and findings will lay a solid foundation to further our scientific understanding of water-soil-vegetation interactions, ultimately leading to the development of practically effective solutions to sustaining the globe's ecosystem health and productivity.…”

“…The specific topics include steppe vegetation affected by climate change [39,40], interactions of climate, anthropogenic activities, and watershed hydrology [41][42][43], SWAT modeling for quantifying topography-controlled hydrologic processes and sediment yield [44,45], snow cover and frozen soil dynamics in cold regions [46], quantification of plant transpiration in arid/semiarid environment [47], coupled infiltration-runoff modeling for slope stability analysis [48], and assessment of nutrients in aquatic systems [49,50]. In terms of methodologies, these studies involve both field/laboratory experiments and mathematical modeling across different scales.…”

“…This case study provides analysis approaches to demonstrate the dominant impact of human activities on streamflow. Lu et al [43] applied the Coupled Model Intercomparison Project Phase 5 (CMIP5) dataset and a large-scale Variable Infiltration Capacity (VIC) hydrologic model to assess the impact of climate change on droughts in the upstream Yangtze River region in China. Their predictions revealed that regional drought could be more severe by the 2030s, in terms of duration, frequency, areal extent, and intensity, demonstrating that coupled climatic and hydrologic modeling can be effectively applied to address the hydrologic extreme issues.…”