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Jiangchao Qiu

Publications and source records attributed to Jiangchao Qiu.

2 recordsLinked to original sources

LASSE: Learning Active Sampling for Storm Tide Extremes in Non-Stationary Climate Regimes

Identifying tropical cyclones that generate destructive storm tides for risk assessment, such as from large downscaled storm catalogs for climate studies, is often intractable because it entails many expensive Monte Carlo hydrodynamic simulations. Here, we show that surrogate models are promising from accuracy, recall, and precision perspectives, and they "generalize" to novel climate scenarios. We then present an informative online learning approach to rapidly search for extreme storm tide-producing cyclones using only a few hydrodynamic simulations. Starting from a minimal subset of TCs with detailed storm tide hydrodynamic simulations, a surrogate model selects informative data to retrain online and iteratively improves its predictions of damaging TCs. Results on an extensive catalog of downscaled TCs indicate 100% precision in retrieving rare destructive storms using less than 20% of the simulations as training. The informative sampling approach is efficient, scalable to large storm catalogs, and generalizable to climate scenarios.

physics.ao-ph

Bangladesh's Amplified Coastal Storm Tide Hazard from Tropical Cyclones and Rising Sea Levels in a Warming Climate

The risk of extreme storm tides to Bangladesh's low-lying and densely populated coastal regions, already vulnerable to tropical cyclones, remains poorly quantified under a warming climate. Here, using a statistical-physical downscaling approach, our multimodel large-ensemble projections under the IPCC6 SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios show that Bangladesh's 100-year storm tide will likely intensify from 3.5 m to between 4.9 m and 5.4 m by the end of the 21st century. The Meghna-North Chattogram region is the most vulnerable, and the storm tide season will broaden significantly, amplifying the strongest during the late monsoon and late post-monsoon seasons. We project substantial increases in seasonal storm tide frequencies, with a four-fold increase in back-to-back extremes in the post-monsoon season. Across the SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios assessed using multiple climate models, the frequency of storm tide from destructive cyclones like Bhola and Gorky will significantly increase by 7-18 times and 6-23 times, respectively. Our study indicates a need to re-examine the ongoing coastal improvement and heighten the urgency to enhance coastal resilience in Bangladesh.

physics.ao-ph