Chen Shuyi S.

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Chen
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Shuyi S.
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  • Article
    An ocean coupling potential intensity index for tropical cyclones
    (John Wiley & Sons, 2013-05-15) Lin, I.-I. ; Black, Peter G. ; Price, James F. ; Yang, C.-Y. ; Chen, Shuyi S. ; Lien, Chun-Chi ; Harr, Patrick ; Chi, N.-H. ; Wu, C.-C. ; D'Asaro, Eric A.
    Timely and accurate forecasts of tropical cyclones (TCs, i.e., hurricanes and typhoons) are of great importance for risk mitigation. Although in the past two decades there has been steady improvement in track prediction, improvement on intensity prediction is still highly challenging. Cooling of the upper ocean by TC-induced mixing is an important process that impacts TC intensity. Based on detail in situ air-deployed ocean and atmospheric measurement pairs collected during the Impact of Typhoons on the Ocean in the Pacific (ITOP) field campaign, we modify the widely used Sea Surface Temperature Potential Intensity (SST_PI) index by including information from the subsurface ocean temperature profile to form a new Ocean coupling Potential Intensity (OC_PI) index. Using OC_PI as a TC maximum intensity predictor and applied to a 14 year (1998–2011) western North Pacific TC archive, OC_PI reduces SST_PI-based overestimation of archived maximum intensity by more than 50% and increases the correlation of maximum intensity estimation from r2 = 0.08 to 0.31. For slow-moving TCs that cause the greatest cooling, r2 increases to 0.56 and the root-mean square error in maximum intensity is 11 m s−1. As OC_PI can more realistically characterize the ocean contribution to TC intensity, it thus serves as an effective new index to improve estimation and prediction of TC maximum intensity.
  • Article
    The CBLAST-Hurricane program and the next-generation fully coupled atmosphere–wave–ocean models for hurricane research and prediction
    (American Meteorological Society, 2007-03) Chen, Shuyi S. ; Zhao, Wei ; Donelan, Mark A. ; Price, James F. ; Walsh, Edward J.
    The record-setting 2005 hurricane season has highlighted the urgent need for a better understanding of the factors that contribute to hurricane intensity, and for the development of corresponding advanced hurricane prediction models to improve intensity forecasts. The lack of skill in present forecasts of hurricane intensity may be attributed, in part, to deficiencies in the current prediction models—insufficient grid resolution, inadequate surface and boundary-layer formulations, and the lack of full coupling to a dynamic ocean. The extreme high winds, intense rainfall, large ocean waves, and copious sea spray in hurricanes push the surface-exchange parameters for temperature, water vapor, and momentum into untested regimes. The Coupled Boundary Layer Air–Sea Transfer (CBLAST)-Hurricane program is aimed at developing improved parameterizations using observations from the CBLAST-Hurricane field program that will be suitable for the next generation of hurricane-prediction models. The most innovative aspect of the CBLAST-Hurricane modeling effort is the development and testing of a fully coupled atmosphere–wave–ocean modeling system that is capable of resolving the eye and eyewall at ~1-km grid resolution, which is consistent with a key recommendation for the next-generation hurricane-prediction models by the NOAA Science Advisor Board Hurricane Intensity Research Working Group. It is also the National Centers for Environmental Prediction (NCEP) plan for the new Hurricane Weather Research and Forecasting (HWRF) model to be implemented operationally in 2007–08.