Introduction

In East Asia, the phenomenon of plum rain brings persistent and extensive rainfall during the summer months, significantly impacting areas from the central and lower reaches of the Yangtze River in China to Kyushu Island in Japan. This seasonal rainfall is crucial for agriculture, but it can also be devastating, as seen in 2020 when an unprecedented “violent plum rain” wreaked havoc across the region, disrupting lives and agricultural productivity.

Need for Enhanced Forecasting

Given the destructive potential of these weather events, there is a pressing need for enhanced subseasonal forecasting capabilities. In a groundbreaking study recently published in *Environmental Research Letters*, a research team headed by Professors Zhao Chun and An Hong from the University of Science and Technology of China (USTC) has made significant strides in this area. Their team utilized the powerful Sunway supercomputer to conduct a one-month subseasonal forecast experiment, successfully replicating the extensive rainbands observed during the catastrophic plum rain of 2020 in Japan.

Development of Integrated Atmospheric Model

This remarkable achievement was made possible due to the development of an integrated atmospheric model across scales (iAMAS) specifically optimized for the high-performance capabilities of the Sunway supercomputer. The team's customized algorithms increased computational efficiency, facilitating monthly forecasts at a fine resolution of just 3 km.

Key Findings from the Research

Through rigorous experimentation with various forecast resolutions, the researchers uncovered critical insights into the predictability of the 2020 plum rain. They discovered that predictions using a global 60 km low-resolution model resulted in a notable northward shift in the expected rainband. Surprisingly, even increasing the resolution to the convection-permitting scale did not resolve this issue. Further examination revealed a significant expansion of the Western North Pacific Subtropical High (WNPSH) at coarser resolutions, illustrating how this atmospheric phenomenon influenced the rainband's position and intensity.

Accurate Simulation of Rainfall Processes

Moreover, this global convection-permitting model has demonstrated its capability to accurately capture deep convection dynamics within the equatorial regions. It effectively simulates rainfall processes and circulation patterns in the Western Pacific, closely matching observational data.

Conclusion and Implications for the Future

As the world grapples with the increasing unpredictability of climate patterns, advancements like these come at a crucial time, promising to improve the accuracy of weather forecasts and potentially saving countless lives and livelihoods in the face of severe weather events.

Stay Tuned

How will this groundbreaking technology reshape the future of disaster preparedness and response in the face of extreme weather?