Introduction

Typhoon Hinnamnor was one of the strongest tropical cyclones in the western North Pacific in 2022. It is a useful case for this study because it showed not only strong intensity but also a complex and unusual track before approaching the Korean Peninsula.

Unlike many typhoons that generally move northwestward or recurve northeastward in a relatively continuous path, Hinnamnor moved southward after formation, slowed down near the southern Ryukyu Islands, formed a looping-like track, and the turned sharply northward toward the Korean Peninsula. These features make it important to examine how different reanalysis datasets represent its track, central pressure, and wind structure.

1. Overview

2. Reanalysis Datasets and Data Assimilation

ERA5 and JRA-55 are both global reanalysis datasets, but previous studies describe several differences in their model systems, resolution, data assimilation, and observation processing. The table below summarizes the dataset characteristics that are most relevant to this study.

3. Research Objectives

This study aims to examine how Typhoon Hinnamnor is represented in different meteorological datasets by focusing on its track, intensity, vertical wind structure, and lower-level atmospheric structure. To do this, the analysis is organized into three main parts: track and intensity error, vertical wind difference, and lower-level case analysis.

First, the track and intensity error analysis compares RSMC and JTWC best-track datasets. By calculating positional differences between corresponding 6-hourly track points and comparing central pressure values, this section examines how the two best-track datasets represent Hinnamnor’s movement and intensity.

Second, the vertical wind difference analysis compares ERA5 and JRA-55 reanalysis datasets. This section focuses on differences in wind fields across different atmospheric levels in order to examine how each dataset represents the vertical structure of the typhoon-related circulation.

Third, the lower-level case analysis investigates the near-surface and lower-tropospheric structure of Hinnamnor during selected key stages, including the landfall period, peak-intensity stage, and dissipation stage. Through these analyses, this study aims to understand how dataset differences may influence the interpretation of Hinnamnor’s track, intensity, and atmospheric structure.

4. Expected Findings

Based on the differences in model resolution, temporal resolution, and data assimilation systems, ERA5 and JRA-55 are expected to represent Typhoon Hinnamnor differently. ERA5 may capture more detailed changes in track, central pressure, and vertical wind structure, while JRA-55 may show a smoother representation of the typhoon. These differences are expected to become more evident during key periods, such as the looping stage, slow-moving stage, and peak-intensity stage.

Therefore, comparing the two datasets can provide insight into how reanalysis characteristics influence the representation of tropical cyclones.