Sensitivity of tropical cyclones to convective parameterization schemes in RegCM4

This study investigates the sensitivity of simulated tropical cyclones (TC) affecting Philippines to convective parameterization schemes (CPS) in Regional Climate Model Version 4 (RegCM4). Five ERA-Interim driven RegCM4 simulations at 25-km horizontal resolution were conducted utilizing CPS Grell with Arakawa–Schubert closure (GR), Emanuel (EM), Kain–Fritsch (KF), Tiedtke (TE), and a combined scheme over land ocean (GR-EM). Comparisons made between observed RegCM4-simulated TCs covering 30-year period (1981–2010) indicate that EM yields an annual-mean TC frequency is closest observations. The GR-EM scheme, on other hand, closely reproduces seasonal patterns tracks, spatial track density TC-associated rainfall, lifespan. KF only was able simulate intense (maximum wind speed > 40 m s–1) within domain. In contrast, both GR TE largely underestimated frequency, weak TCs. Such underestimation intensity can be attributed dry mid-tropospheric environment absence large area positive low-level relative vorticity Pacific Ocean inhibiting formation further development area. These findings would helpful selecting more appropriate for TC-related model improvements, given climate modeling imperfections associated biases.