Estimating Typhoon Waves based on the Modified ECMWF ERA-5 Wind Data

Abstract

ERA-5 is a recently released reanalysis meteorological dataset provided by European Centre for Medium-Range Weather Forecasts (ECMWF). This study evaluates the representation of tropical cyclones (TC) in ERA-5 and the widely used ECMWF ERA-Interim (ERA-I) reanalysis data in the northwest Pacific region during year 2013 to 2015. Although ERA-5 wind data has a great improvement of precision during TC period than ERA-I data, it is still not accurate enough for the description of TCs especially when it is applied to estimate typhoon waves. To effectively correct this data, an empirical correlation is established between the maximum wind speed of TCs in ERA-5 and Best-track data. Then the ERA-5 data can be improved using a directly modified method without the requirement of observation TC track data. The modified ERA-5 wind data, the original ERA-5 data and the ERA-I data are applied to drive the FVCOM-SWAVE wave model to estimate the typhoon waves. The typhoon waves driven by the modified ERA-5 data show a better performance than that driven by other two wind datasets. The method introduced in this study for modification of ERA-5 wind data provides an alternative for the correction of this data during TC period when the observation TC track is unavailable.