• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.5
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• pp.291-300
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• 2013

Typhoon simulation method is widely used to estimate sea surface wind speeds during the typhoon periods. Holland (1980) model has been regarded to provide relatively better results for observed wind data. JTWC or RSMC best track data are available for typhoon modeling, but these data show slightly different because the data generation process are different. In this paper, a Newton-Raphson method is used to solve the two nonlinear equations based on the Holland model that is formed by the two typhoon parameters, i.e. the longest radius of 25 m/s and 15 m/s wind speeds, respectively. The solution is the radius of maximum wind speed which is of importance for typhoon modeling. This method is based on the typhoon wind profile of JMA and it shows that Holland model appears to fit better the characteristics of typhoons on the temporal and spatial changes than that of the other models. In case of using RSMC best track data, the method suggested in this study shows better and more reasonable results for the estimation of radius of maximum wind speed because the consistency of the input data is assured.

• Atmosphere
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• v.32 no.4
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• pp.381-394
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• 2022

The Korea Meteorological Administration (KMA) National Typhoon Center has been officially releasing reanalyzed best tracks for the previous year's northwest Pacific typhoons since 2015. However, while most typhoon researchers are aware of the data released by other institutions, such as the Joint Typhoon Warning Center (JTWC) and the Regional Specialized Meteorological Center (RSMC) Tokyo, they are often unfamiliar with the KMA products. In this technical note, we describe the best track data released by KMA, and the algorithms that are used to generate it. We hope that this will increase the usefulness of the data to typhoon researchers, and help raise awareness of the product. The best track reanalysis process is initiated when the necessary database of observations-which includes satellite, synoptic, ocean, and radar observations-has become complete for the required year. Three categories of best track information-position (track), intensity (maximum sustained winds and central pressure), and size (radii of high-wind areas)-are estimated based on scientific processes. These estimates are then examined by typhoon forecasters and other internal and external experts, and issued as an official product when final approval has been given.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.4
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• pp.252-261
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• 2020

Numerical simulations of the storm surge and waves induced by the Typhoon Kong-Rey incident on the south coast of Korea in 2018 are conducted using the JMA-MSM weather field provided by the Japan Meteorological Agency, and the calculated surge heights are compared with the time history observed at harbours along the south-east coast. For the waves occurring coincidentally with the storm surges the calculated significant wave heights are compared with the data measured using the wave buoys operated by the KHOA (Korea Hydrographic and Oceanographic Agency) and the KMA (Korea Meteorological Administration), and the data observed at AWAC stations of the KIOST (Korea Institute of Ocean Science and Technology). Additional simulations are also performed based on the pressure and wind fields obtained using the best track information provided by the JTWC (Joint Typhoon Warning Center) of the United States, and the results are compared and analyzed. Based on the results of this study it is found that the reliable weather fields are essential for the accurate simulation of storm surges and waves.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.4
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• pp.273-283
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• 2020

Numerical simulations of the storm surge and waves induced by the Typhoon Bolaven incident on the west sea of Korea in 2012 are performed using the JMA-MSM weather field provided by the Japan Meteorological Agency, and the calculated surge heights are compared with the time history observed at harbours along the various coasts of Korea. For the waves occurring coincidentally with the storm surges the calculated significant wave heights are compared with the data measured using the wave buoys operated by the Korea Hydrographic and Oceanographic Agency and the Korea Meteorological Administration. Additional simulations are also performed based on the pressure and wind fields obtained using the best track information provided by the Joint Typhoon Warning Center, and the calculated results are compared and analyzed. The waves and storm surges calculated using JMA-MSM wether field agree well with the observations because of the better reflection of the topography and the pre-background weather field. On the other hand, the calculated results based on the weather fields produced using the JTWC best track information show some limitations of the general trend of the variations of wave and surge heights. Based on the results of this study it is found that the reliable weather fields are essential for the accurate simulation of storm surges and waves.