Systematic errors in regional climate simulation of East Asian winter monsoon
- 1Ulsan National Institute of Science and Technology, Urban and Environmental Engineering, Korea, Republic of
- 2Pohang University of Science and Technology, Division of Environmental Science and Engineering, Korea, Republic of
East Asian Winter Monsoon (EAWM) is an important system, which has impact on extreme winter phenomena, in East Asia including the Korean Peninsula. EAWM is characterized by the Siberian high with cold air and the Aleutian low with warm air, low-level northerly wind between them, East Asian trough in the middle troposphere, and East Asian jet stream in the upper troposphere. According to some previous studies, the variability of EAWM, which can be influenced by human activity and climate change, is strongly correlated with the occurrence of cold waves in East Asia. Additionally, EAWM variability has been shown to affect the precipitation during winter on the Korean Peninsula. Extreme boreal winter phenomena such as cold waves and heavy snow related to EAWM can induce disruptions to regular life and socio-economic damage. Regional climate models (RCMs) have added value in the simulations of extreme climate phenomena, but also have internal variability, which can increase uncertainty in future climate projections. Therefore, in this study, to closely understand EAWM and reduce the uncertainty in future climate projection, the performance of two RCMs (SNURCM and WRF) for EAWM simulation was evaluated. The results showed that two RCMs had the ability to capture the interannual variability and climatological spatial pattern of EAWM despite the systematic biases of EAWM in the lower troposphere (e.g., comparatively low correlation and larger temporal-spatial variability than reanalysis). Additionally, two RCMs presented significant cold bias over the Manchuria and wet bias over the Kuroshio Current. In further analysis, their systematic errors were positively correlated with EAWM, which had a larger pressure gradient between the Siberian high and the Aleutian low and colder advection over Manchuria than those of the ERA5. Wet biases over the Kuroshio Current could be related to unreasonable simulation EAWM induced by uncoupled air-sea interaction in RCMs.
How to cite: Shin, S.-W., Lee, M., Park, C.-Y., Kim, E., Mun, T., Juzbašić, A., and Cha, D.-H.: Systematic errors in regional climate simulation of East Asian winter monsoon, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15005, https://doi.org/10.5194/egusphere-egu23-15005, 2023.
