Selection of Effective GCM Bias Correction Methods and Evaluation of Hydrological Response under Future Climate Scenarios

Yaogeng Tan,Zengchuan Dong,Liang Tan,Sandra M Guzman

doi:10.3390/cli8100108

Yaogeng Tan, Zengchuan Dong + Show 2 more

Open Access

https://doi.org/10.3390/cli8100108

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Journal: Climate	Publication Date: Sep 30, 2020
Citations: 16	License type: CC BY 4.0

Affiliation: Hohai University, University of Florida

Abstract

Global climate change is presenting a variety of challenges to hydrology and water resources because it strongly affects the hydrologic cycle, runoff, and water supply and demand. In this study, we assessed the effects of climate change scenarios on hydrological variables (i.e., evapotranspiration and runoff) by linking the outputs from the global climate model (GCM) with the Soil and Water Assessment Tool (SWAT) for a case study in the Lijiang River Basin, China. We selected a variety of bias correction methods and their combinations to correct the lower resolution GCM outputs of both precipitation and temperature. Then, the SWAT model was calibrated and validated using the observed flow data and corrected historical GCM with the optimal correction method selected. Hydrological variables were simulated using the SWAT model under emission scenarios RCP2.6, RCP4.5, and RCP8.5. The results demonstrated that correcting methods have a positive effect on both daily precipitation and temperature, and a hybrid method of bias correction contributes to increased performance in most cases and scenarios. Based on the bias corrected scenarios, precipitation annual average, temperature, and evapotranspiration will increase. In the case of precipitation and runoff, projection scenarios show an increase compared with the historical trends, and the monthly distribution of precipitation, evapotranspiration, and runoff shows an uneven distribution compared with baseline. This study provides an insight on how to choose a proper GCM and bias correction method and a helpful guide for local water resources management.

Highlights

Global climate change and its impact on hydrology and water resources have received special attention due to its effects on land use and development [1]
According to the 4th version of the World Water Development Report (WWDR), the availability of water resources will decrease as the human demand for water increases continuously
global climate model (GCM) simulating itself and the ECDFbias method of biasAccording correctiontoperform relatively wellininthis higher of itself and the method of bias correction perform relatively well in higher latitudes and and elevations where there is less precipitation, which brings about less uncertainty compared with elevations where there is less precipitation, which brings about less uncertainty compared with humid and subtropical areas [1,16]

Summary

Introduction

Global climate change and its impact on hydrology and water resources have received special attention due to its effects on land use and development [1]. According to the fifth assessment report of Intergovernmental Panel on Climate Change (IPCC5), the average global surface temperature has risen by 1.5 ◦ C since the industrial revolution, confirming that climate change is happening all over the world [2,3] and brings out more obvious fluctuation of precipitation and evaporation at both annual and interannual scales. This changing climate will eventually influence hydro systems, including spatial and temporal runoff distribution as well as available water resources [4].

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