Evaluation of Warm-Core Structure in Reanalysis and Satellite Data Sets Using HS3 Dropsonde Observations: A Case Study of Hurricane Edouard (2014)

Using National Aeronautics and Space Administration Hurricane and Severe Storm Sentinel (HS3) dropsonde observations in the eye of Hurricane Edouard (2014), its warm-core structure in reanalysis/analysis and satellite data sets are evaluated. All of the data sets generally underestimate the warm-core strength of Edouard. Advanced Microwave Sounding Unit-A shows the smallest error in the upper troposphere but the largest error in the lower troposphere. Its successor, Advanced Technology Microwave Sounder, significantly improves the representation of low-level warming while maintaining its performance in the middle and upper troposphere. Two versions of the Global Forecast System analysis at different resolutions and Climate Forecast System Reanalysis version 2 show better performance than the other reanalyses. Modern Era Retrospective Analysis for Research and Application (MERRA)-2, Japanese 55-year Reanalysis, and European Centre for Medium-Range Weather Forecasts Interim Reanalysis could represent the vertical warm-core structure, but they markedly underestimate the warm-core strength. MERRA and North American Regional Reanalysis (especially North American Regional Reanalysis) have the worst skills when reproducing warm cores. MERRA-2 considerably outperforms its predecessor, MERRA. The warm-core evolution of Edouard in six reanalysis/analysis data sets is diagnosed and compared. Different physical processes such as diabatic heating and vertical and horizontal advection may be responsible for warm-core generation at different stages during its lifetime. The inaccurate representation of these physical processes in the reanalyses/analyses results in errors in the warm-core strength and height. It is suggested that vortex relocation/bogusing, assimilation of tropical cyclone (TC) observation data, and model parameterizations are important to adequately represent warm cores in terms of strength and three-dimensional structure. This study can shed some light on the selection of suitable data sets for estimating the real-time warm-core strength or for TC-related climate studies. The need for better observations of TCs and model improvements is also highlighted.