Interagency discrepancies in tropical cyclone intensity estimates over the western North Pacific in recent years

• Published in: Atmospheric science letters Vol. 24; no. 1
• Main Authors: Bai, Lina, Xu, Yinglong, Tang, Jie, Guo, Rong
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.01.2023; John Wiley & Sons, Inc; Wiley
• Subjects: Atmospheric sciences; best track dataset; Coastal zone; Conversion; Cyclones; Datasets; Estimates; Hurricanes; intensity estimation; Maximum winds; Oceans; Offshore; Satellites; Trends; tropical cyclone; Tropical cyclone intensities; Tropical cyclones; Typhoon warnings; Typhoons; western North Pacific; Wind speed
• ISSN: 1530-261X; 1530-261X
• DOI: 10.1002/asl.1132

This study investigates interagency discrepancies among best‐track estimates of tropical cyclone (TC) intensity in the western North Pacific, provided by the Joint Typhoon Warning Center (JTWC), the China Meteorological Administration (CMA), and the Regional Specialized Meteorological Center (RSMC) Tokyo during 2013 to 2019. The results reveal evident differences in maximum wind speed (MSW) estimates, where linear systematic differences are significant. However, the Dvorak parameter (CI) numbers derived from the MSWs reported by the three agencies are internally consistent. Further analysis suggests that the remained CI discrepancies are related to differences in the estimation of intensity trends, initial intensities, and TC positions among these datasets. In addition, the CI estimates provided by the JTWC for TCs over the open ocean are generally higher than those reported by the CMA and RSMC. However, the estimates from CMA and RSMC tend to give higher TC intensities for the TCs in the mainland and coastal areas of China and Japan, respectively, than those over the open ocean with the same intensity in JTWC dataset. This pattern potentially reflects the extensive use of surface observations by these two agencies for landfalling and offshore TCs. These results may help the research community to get more accurate details about the TCs in WNP from the best track datasets of different agencies. Boxplots depicting interagency differences in MSW and CI between pairs of BTDs. (a) MSWJTWC–MSWCMA versus MSWJTWC; (b) CIJTWC–CICMA versus CIJTWC; (c) MSWJTWC–MSWRSMC versus MSWJTWC; (d) CIJTWC–CIRSMC versus CIJTWC; (e) MSWCMA–MSWRSMC versus MSWRSMC; and (f) CICMA–CIRSMC versus CIRSMC. Solid red lines indicate the average value for each group. Thick black lines indicate the difference is equal to zero.