AIR Worldwide Introduces Inland Flood Model for Japan

October 23, 2017

Catastrophe modeling firm AIR Worldwide has introduced a new inland flood model for Japan along with enhancements to its Japan typhoon model. These models are part of Version 5.1 of AIR’s catastrophe modeling software platform, Touchstone.

The AIR Inland Flood Model for Japan is an innovative model that explicitly simulates the effects of on- and off-plain inland flooding from sources other than tropical cyclones. Non-tropical systems that trigger inland flooding account for 40 percent of flood losses in Japan.

The new probabilistic model captures the complexities of the flood peril in an area of more than 377,000 square kilometers, divided into over 20,000-unit catchments for a river network exceeding 100,000 km in length – and takes flood defenses into consideration, said a statement from AIR, which is a Verisk business.

The model was calibrated and validated using observational data based on river flows at nearly 1,000 locations, as well as lake and dam storage data from more than 2,000 locations.

The model generates flood events by way of a large-scale hydrological model that simulates continuous surface runoff and river flows using a method that learns the patterns of precipitation from observed tropical cyclone and non-tropical cyclone systems, the company explained.

The model takes into account river shape, dams, levees, and other structures when computing discharge at each location along the river network. Preexisting conditions, such as lake and dam storage and soil saturation, which can exacerbate flood conditions, are accounted for.

The new inland flood model can be used with AIR’s Japan typhoon model for a comprehensive understanding of Japanese flood risk. This model, updated to include a completely new typhoon-induced precipitation module, also captures the risk from wind and storm surge. Both Japan models are released in Touchstone 5.1, which also features significant enhancements to the geospatial module.

The improved architecture has resulted in significant reductions in analysis run times, the company said.

“Until now, the industry has lacked the tools to effectively quantify inland flood risk in Japan,” said Dr. Jayanta Guin, chief research officer at Boston-based AIR Worldwide. “We’re excited to add Japan to our growing portfolio of high-resolution flood models. The model represents another step forward in helping the industry manage this complex risk by better understanding the severity, frequency, and loss potential of extreme flood events in Japan.”

“These latest updates will continue to simplify companies’ risk management workflows while also helping them develop their own view of risk in one easy-to-use, comprehensive risk management platform,” said Rob Newbold, executive vice president at AIR Worldwide.

The AIR Inland Flood and Typhoon Models for Japan are available in the Touchstone Version 5.1 and CATRADER® Version 19.1 catastrophe risk management systems.

Source: AIR Worldwide

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