Statistical-based model development with surrogate rainfall fields and its use to assess typhoon rain hazard for coastal region of mainland China

Abstract

Tropical cyclones (TCs) could cause intense rainfall along the coastal region of mainland China. The modeling of rainfall intensity could be carried out using snapshots of the rainfall intensity field obtained from satellite data such as those from the Tropical Rainfall Measuring Mission (TRMM) satellite data. In the present study, both the precipitation radar TRMM (PR-TRMM) data and the Microwave Imager (TMI) TRMM (TMI-TRMM) data that affect onshore sites in mainland China are considered to develop rainfall intensity models. To augment the database for the model development, surrogates of the snapshots are generated using an efficient iterative simulation algorithm and applying the discrete orthogonal S-transform. The simulated surrogates for the seed snapshots follow the same marginal distribution and power spectral density distribution. Empirical models of the rainfall intensity are developed using the surrogates so to increase the sample size. For the development, the TC rainfall intensity field is represented as a superposition of the axisymmetric, asymmetric, and topographic components. This consideration is guided by the parametric hurricane rain model (PHRaM) available in the literature. It is shown that the rainfall intensity inferred from the snapshots from PR-TRMM is greater than that from the snapshots from TMI-TRMM. The developed models are used in a simulation framework to map TC rain hazard (in terms of the return period value of the annual maximum accumulated rain per day).