Applications of Local Spectral Width on GPS RO Data Assimilation to Operational Typhoon Track Forecasts

Yu-Chun Chen ； Ming-En Hsieh ； Hui Liu ； Ling-Feng Hsiao ； Lung-Yao Chang ； Ching-Yuang Huang ； Ying-Hwa Kuo

《Journal of Aeronautics, Astronautics and Aviation》 50卷4期 Vol.50 No.4 Formosat-7 (NSPO) Special Issue (2018/12) Pp. 415-427

https://doi.org/10.6125/JoAAA.201812_50(4).07

摘要

Owing to the inhomogeneous distribution of water vapor in the lower troposphere, the multi-path propagation of radio waves from Global Positioning System (GPS) causes the divergent measurement from radio occultation. Hence, local spectral width (LSW) of wave optics transformed bending angles spectrum can be used to represent the uncertainty of radio occultation (RO) observation. In this study, the LSW is applied to a physically-based quality control of Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) GPSRO refractivity data assimilated in the Typhoon Weather Research and Forecasting (TWRF) system, the regional operational model, at Central Weather Bureau (CWB) in Taiwan. The results show a track forecast improvement for a typhoon Sinlaku case initiated at 1800UTC 11 September in 2008. The results for the sequential cycling experiments of typhoons (Sinlaku, Hagupit, and Jangmi in September 2008) also imply the potential benefits of LSW-based GPSRO data QC on the typhoon track forecasts.

關鍵字

GPS ； radio occultation ； typhoon ； local spectral width