Added value of high-resolution climate projections over South Korea on the scaling of precipitation with temperature

Abstract

This study evaluates the resolution dependency of scaling precipitation with temperature from the perspective of the added value of high-resolution (5 km) dynamical downscaling using various kinds of long-term climate change projections over South Korea. Three Coupled Model Intercomparison Project Phase 5 (global climate models (GCMs) with different climate sensitivities, and one pseudo global warming (PGW) experiment, are downscaled by Weather Research and Forecasting one-way double nested modeling system with convective parameterization for the reference (1976–2005) and future (2071–2100) periods under RCP8.5 scenario. A detailed comparison of the driving GCM/PGW, 20 km mother simulation, and 5 km nested simulation demonstrates improved representation of precipitation with increasing resolution not only in the spatial pattern and magnitude for both the mean and the extremes, but also in a more realistic representation of extreme precipitation’s sensitivities to temperature. According to the projected precipitation changes downscaled from both GCM ensemble and PGW, there will be intensified precipitation, particularly for the extremes, over South Korea under the warming, which is primarily contributed by convective precipitation increase that shows higher temperature sensitivity. This study also compares the extreme precipitation-temperature scaling relations within-epoch (apparent scaling) and between-epoch (climate scaling). It confirms that the magnitude and spatial pattern of the two scaling rates can be quite different, and the precipitation change over Korea under global warming is mainly controlled by thermodynamic factors.