Extreme precipitation
Extreme weather is changing its form all over the world due to the climate change. Here, I am working research focusing on atmospheric rivers, that are known to bring extreme precipitation and flooding to the US West Coast.
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Subseasonal forecast of atmospheric rivers
It is known that the Madden-Julian Oscillation (MJO) in the tropical atmosphere modulate atmospheric river activity in 2-5 weeks time scale. However, there is large uncertainty in actual forecasts due to many other factors. In this study, we demonstrated that low-frequency variability of the Pacific/North American (PNA) mode can significantly improve atmospheric forecasts in this time scale.
Ref: (Toride and Hakim, 2021)
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Probable maximum precipitation (PMP) estimation
PMP is the theoretical maximum precipitation that could fall over a particular region. The concept of PMP is widely used for the design and risk assessment of water resource infrastructure. We estimated PMP with realistically maximized storms in a Pacific Northwest region using an atmospheric model. We proposed a method that only perturbs moisture along the path of atmospheric rivers based on vertically integrated water vapor flux. We found that it creates more realistic atmospheric fields and more severe precipitation compared to the method used in previous studies.
Ref: (Toride et al., 2019)
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Climate change analysis
We analyzed long-term trends in 160-year precipitation reconstructed over two watersheds along the US West Coast using a regional atmospheric model. We found increasing trends in extreme precipitation, a sharp increase in the variability of annual precipitation, and inconsistency with the trends at a regional scale.
