- Academia Sinica, Research Center for Environmental Changes, Taipei City,, Taiwan (rising74928@gmail.com)
This study presents a revised Tropical Cyclone Genesis Potential Index (χMqGPI) for projecting tropical cyclone genesis in the Western North Pacific (WNP) and evaluates its performance against the traditional χGPI index. Using simulations from 22 CMIP6 models, both indices were calculated and assessed for their accuracy in historical and future warming scenarios. The results indicate that in historical simulations, both χGPI and χMqGPI exhibit strong correlations with observed tropical cyclone data, with correlation coefficients exceeding 0.9. Both indices also effectively capture the primary genesis regions of tropical cyclones in the WNP in terms of spatial distribution.
Under future warming scenarios, however, the two indices project contrasting trends in tropical cyclone genesis frequency (TCGF). χGPI consistently predicts an increase in TCGF, while χMqGPI projects a declining trend that aligns more closely with recent findings from high-resolution models. This declining trend underscores the robustness and reliability of χMqGPI in climate projections.
Decomposition analysis of χMqGPI revealed that large-scale dynamic parameters, particularly absolute vorticity and vertical wind shear, are critical in explaining discrepancies between model simulations. These differences become increasingly pronounced with the severity of warming, highlighting the importance of accurately representing large-scale environmental dynamics in models to improve tropical cyclone projections under climate change.
These findings offer valuable insights into the potential future behavior of tropical cyclones and emphasize the significance of adopting refined indices, such as χMqGPI, for reliable climate predictions. This work underscores the critical role of advanced metrics in understanding the impact of global warming on tropical cyclone activity in the WNP and beyond
How to cite: Hsiao, L.-P. and Hsu, H.-H.: Evaluating the Impact of Global Warming on Tropical Cyclone Genesis in the Western North Pacific: A Comparative Study of Tropical Cyclone Genesis Indices Using CMIP6 Models, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7700, https://doi.org/10.5194/egusphere-egu25-7700, 2025.
