Abstract
High resolution models from the High-Resolution Model Intercomparison Project (HighResMIP), part of CMIP6, have the capacity to allow a better representation of the climate system in tropical regions, but how different model resolutions affect hydrological outputs remains unclear. This research aims to evaluate projections of hydro-climatic change of the Johor River Basin (JRB) in southern Peninsular Malaysia between 1985 to 2015 and 2021 to 2050, focusing on uncertainty quantification of hydrological outputs from low (>1°), medium (0.5° to 1°) and high (≤0.5°) horizontal resolution models. These projections show future increases in annual precipitation of 0.4 to 3.1%, minimum and maximum temperature increases of 0.8 to 0.9 °C and 0.9 to 1.1 °C, respectively. These projected climate changes lead to increases in annual mean streamflow of 0.9% to 7.0% and surface runoff of 7.0% to 20.6% in the JRB. These annual mean changes are consistent with those during the wet period (November to December), e.g., streamflow increases of 4.9% to 10.8% and surface runoff of 28.8 to 39.9% in December. Disagreement in the direction of change is found during the dry seasons, (February to March and May to September), where high resolution models project a decrease in future monthly precipitation and streamflow, whilst increases are projected by the medium- and low-resolution models.
Highlights
Hydro-climatic projection provides critical information for promoting disaster mitigation, sustainable urban planning, ecological analysis and water resource and agricultural management under future climate change
The Johor River Basin (JRB) has been divided into 23 sub-basins and 151 Hydrologic Response Units (HRUs)
CN2 that linked to surface runoff has been regarded as the most sensitive parameter in Soil and Water Assessment Tool (SWAT) modeling in many tropical river basins [16,53,54]
Summary
Hydro-climatic projection provides critical information for promoting disaster mitigation, sustainable urban planning, ecological analysis and water resource and agricultural management under future climate change. GCMs have undergone numerous evolutions from capturing realistic regional climate patterns by a few modelers during the 1960s–1970s to solving the major technical features of the climate by a group of international modelling communities in the late 1990s [5] These developments have made GCMs a crucial source of information for investigating the changing state of climate systems, for their uses in the recently released sixth assessment report of the Intergovernment Panel in Climate Change (IPCC), providing the latest physical science basic of climate change for policy makers and the public [5,6]. The use of the CMIP6 in hydrological studies is relatively rare, but such outputs are likely to increase dramatically in the near future [2]
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