Impacts of New Implementing Strategies for Surface and Model Physics Perturbations in TREPS on Forecasts of Landfalling Tropical Cyclones

Abstract To improve the ensemble prediction system of tropical regional atmosphere model for South China Sea (TREPS) in predicting landfalling cyclones (TCs), impacts three new implementing strategies surface and physics perturbations TREPS were evaluated 19 TCs making landfall during 2014–16. For sea temperature (SST) perturbations, spatially uncorrelated random replaced with correlated ones. The multiplier f , which is used to form perturbed tendency Stochastically Perturbed Parameterization Tendency (SPPT) scheme, was inflated regions evident convective activity ( -inflated SPPT). Lastly, (SPP) scheme 14 parameters selected from planetary boundary layer, microphysics, cumulus convection parameterizations added. Overall, all these methods improved forecasts more significantly non-intensifying than intensifying TCs. Compared SPPT, SST generally showed comparable performance but (less) skillful (non-intensifying) advantages SPPT mainly present deterministic guidance both TC track wind probabilistic reliability wind. TCs, adding SPP led mixed significant improvements probability-matched mean modest winds rainfall; while frequently positive on track, intensity, strong winds, moderate rainfall discrimination rainfall.