Enhancing Streamflow Modeling by Integrating GRACE Data and Shared Socio-Economic Pathways (SSPs) with SWAT in Hongshui River Basin, China

Abstract

Climatic variability and the quantification of climate change impacts on hydrological parameters are persistently uncertain. Remote sensing aids valuable information to streamflow estimations and hydrological parameter projections. However, few studies have been implemented using remote sensing and CMIP6 data embedded with hydrological modeling. This research studied how changing climate influences the hydro-climatic parameters based on the earth system models that participated in the sixth phase of the Coupled Model Intercomparison Project (CMIP6). GRACE evapotranspiration data were forced into the Soil and Water Assessment Tool (SWAT) to project hydrologic responses to future climatic conditions in the Hongshui River basin (HRB) model. A novel approach based on climate elasticity was utilized to determine the extent to which climate variability affects stream flow. CMIP6 SSPs (shared socio-economic pathways) for the second half of the 20th century (1960–2020) and 21st century (2021–2100) projected precipitation (5–16%) for the whole Hongshui River basin (HRB). The ensemble of GCMs projected an increase of 2 °C in mean temperature. The stream flow is projected to increase by 4.2% under SSP-1.26, 6.2% under SSP-2.45, 8.45% under SSP-3.70, and 9.5% under SSP-5.85, based on the average changes throughout the various long-term future scenarios. We used the climate elasticity method and found that climate change contributes 11% to streamflow variability in the Hongshui River basin (HRB). Despite the uncertainty in projected hydrological variables, most members of the modeling ensemble present encouraging findings for future methods of water resource management.

Improvement of the Soil and Water Assessment Tool Model and Its Application in a Typical Glacial Runoff Watershed: A Case Study of the Qarqan River Basin, China

“…The data set is provided by Cold and Arid Regions Sciences Data Center at Lanzhou (www.ncdc.ac.cn/ accessed on 15 July 2023). The First Glacier Catalog Data was primarily constructed from aerial survey maps circa 1987, while the Second Glacier Catalog Data was based on remote sensing images captured between 2007 and 2013 [32][33][34]. Considering that there is less human activity intervention in the upstream part of the research area, this study used the First Glacier Catalog Data for the calibration period and the Second Glacier Catalog Data for the verification period (2010-2019).…”

“…The SWAT (Soil and Water Assessment Tool) model, which is renowned for its high computational efficiency and robust applicability, is capable of performing long-time-series continuous simulations. It was developed by the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA) in the 1990s, building upon the SWRBB (Simulator for Water Resources in Rural Basins) model [32,35,36]. In this study, to enhance the accuracy of the original SWAT model in simulating glacier basin runoff, a glacier melt module based on material balance was integrated into the original SWAT model.…”

“…Next, the t-test method was used to perform a sensitivity analysis on the simulated parameters of the SWAT-Gla model [32]. The sensitivities of the above parameters are shown in Figure 6.…”