Objective identification of potentially damaging tropical cyclones over the Western North Pacific

Abstract

An impact-oriented objective windstorm identification algorithm (WiTRACK ), originally developed and well established for studies on extra-tropical storms, is further developed to identify damage and loss related Tropical Cyclones (TC) over the Western North Pacific. Results based on JRA-55 reanalysis data reveal that WiTRACK is able to detect the majority of strong events with hitrates of about 77%/90%/98% for TCs of the three most severe categories. Using economic loss data for China, it is found that especially events with large losses are associated with a windstorm event identified by WiTRACK. Past loss events successfully tracked by WiTRACK are associated with substantially higher losses than those events, not identified by WiTRACK. Thus, even though less skilful than traditional detection schemes if evaluated for the totality of TC events, WiTRACK is a powerful tool to identify severe, damage and loss-related TC events which additionally benefits from its simplicity and minimal input data demands. The latter may allow to apply WiTRACK to datasets not meeting the data requirements of more complex TC detection schemes.

On the Dependency of Atlantic Hurricane and European Windstorm Hazards

“…Befort et al. (2020) has recently demonstrated the skill of WiTRACK in tracking TCs in the West Pacific, and we apply it here for the first time to Atlantic hurricanes so that the damage potential from both seasons can be compared directly.…”

“…For both European windstorms and TCs, events are classified by identifying and tracking clusters of wind speed exceeding a local threshold. Classification is performed using the algorithm WiTRACK (introduced by Leckebusch et al., 2008, applied in Befort et al., 2020; Kruschke, 2015; Renggli et al., 2011). For the local threshold, the 98th percentile is chosen because of its association with extratropical cyclone‐related damage over Europe (Klawa & Ulbrich, 2003).…”

“…For the local threshold, the 98th percentile is chosen because of its association with extratropical cyclone-related damage over Europe (Klawa & Ulbrich, 2003). Befort et al (2020) show the majority of high-impact TCs can also be captured by this method. TCs are excluded beneath a wind speed exceedance area of 15,000 km 2 , while European windstorms are excluded beneath a wind speed exceedance area of 130,000 km 2 .…”

“…WiTRACK was primarily developed for assessing damage potential of European windstorms (Leckebusch et al, 2008) and has been validated extensively for this application (Donat et al, 2010;Kruschke, 2015;Osinski et al, 2015;Renggli et al, 2011;Walz et al, 2018). Befort et al (2020) has recently demonstrated the skill of WiTRACK in tracking TCs in the West Pacific, and we apply it here for the first time to Atlantic hurricanes so that the damage potential from both seasons can be compared directly.…”

A new view on the risk of typhoon occurrence in the western North Pacific

“…The TIGGE data archive has been used extensively in the study of TC activity forecast (e.g. Vitart et al, 2012;Belanger et al, 2012;Halperin et al, 2013;Majumdar and Torn, 2014;Leonardo and Colle, 2017;Luitel et al, 2018). The TIGGE data archive consists of ∼ 8-15 d ensemble forecast data from 10 numerical weather prediction (NWP) centres with about 11-50 members each.…”