Validation and Application of Altimetry-Derived Upper Ocean Thermal Structure in the Western North Pacific Ocean for Typhoon-Intensity Forecast
NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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This paper uses more than 5000 colocated and near coincident in-situ profiles from the National Oceanic and Atmospheric AdministrationGlobal Temperature and Salinity Profile Program database spanning over the period from 2002 to 2005 to systematically validate the satellite-altimetry-derived upper ocean thermal structure in the western North Pacific Ocean as such ocean thermal Structure information is critical in typhoon-intensity change. It is found that this satellite-derived information is applicable in the central and the southwestern North Pacific covering 122-170 degrees E, 9-25 degrees N but not in the northern part 130-170 degrees E, 2540 degrees N. However, since 80 of the typhoons are found to intensify in the central and southern part, this regional dependence should not pose a serious constraint in studying typhoon intensification. Further comparison with the U.S. Naval Research Laboratorys North Pacific Ocean NowcastForecast System NPACNFS hydrodynamic ocean model shows similar regional applicability, but NPACNFS is found to have a general underestimation in the upper ocean thermal structure and causes a large under-estimation of the tropical cyclone heat potential TCHP by up to 60 klsq cm. After validation, the derived upper ocean thermal profiles are used to study the intensity change of super typhoon Dianmu 2004. It is found that two upper ocean parameters, i.e., a typhoons self-induced cooling and the during-typhoon TCHP, are the most sensitive parameters with R2 - 0.7 to the 6-h intensity change of Dianmu during the study period covering Dianmus rapid intensification to category 5 and its subsequent decay to category 4. This paper suggests the usefulness of satellite-based upper ocean thermal information in future research and operation that is related to typhoon-intensity change in the western North Pacific.
- Test Facilities, Equipment and Methods
- Fluid Mechanics