The Sensitivity of WRF Downscaled Precipitation in Puerto Rico to Cumulus Parameterization and Interior Grid Nudging

Abstract

The sensitivity of the precipitation over Puerto Rico that is simulated by the Weather Research and Forecasting (WRF) Model is evaluated using multiple combinations of cumulus parameterization (CP) schemes and interior grid nudging. The NCEP–DOE AMIP-II reanalysis (R-2) is downscaled to 2-km horizontal grid spacing both with convective-permitting simulations (CP active only in the middle and outer domains) and with CP schemes active in all domains. The results generally show lower simulated precipitation amounts than are observed, regardless of WRF configuration, but activating the CP schemes in the inner domain improves the annual cycle, intensity, and placement of rainfall relative to the convective-permitting simulations. Furthermore, the use of interior-grid-nudging techniques in the outer domains improves the placement and intensity of rainfall in the inner domain. Incorporating a CP scheme at convective-permitting scales (<4 km) and grid nudging at non-convective-permitting scales (>4 km) improves the island average correlation of precipitation by 0.05–0.2 and reduces the island average RMSE by up to 40 mm on average over relying on the explicit microphysics at convective-permitting scales with grid nudging. Projected changes in summer precipitation between 2040–42 and 1985–87 using WRF to downscale CCSM4 range from a 2.6-mm average increase to an 81.9-mm average decrease, depending on the choice of CP scheme. The differences are only associated with differences between WRF configurations, which indicates the importance of CP scheme for projected precipitation change as well as historical accuracy.

High‐resolution dynamically downscaled rainfall and temperature projections for ecological life zones within Puerto Rico and for the U.S. Virgin Islands

“…Some important WRF model options include applying analysis nudging within the outer two domains and using a convective parameterization scheme for the innermost domain to reduce rainfall bias, as discussed in detail within Wootten et al . (2016). The following physics options were selected for the WRF simulations: Radiation—RRTMG (Iacono et al ., 2008) Microphysics—WSM6 (Hong and Lim, 2006) Planetary Boundary Layer—YSU (Hong et al ., 2006) Land Surface—Noah (Chen and Dudhia, 2001) Convection—Modified Kain Fritsch (Herwehe et al ., 2014) …”

“…In particular, the CNRM 20th-century simulations improve the fidelity of the annual temperature cycle compared to other CMIP5 models (see figure 5 of Ryu and Hayhoe, 2014) and simulate the seasonal precipitation cycle that realistically reflects both a mid-summer drought and two precipitation peaks within the Caribbean (see table 3 of Hayhoe, 2013). et al, 2014) with significant rainfall reduction, −23%, for RCP8.5 by mid-century with a mean warming of 1.3 C. Finally, the best performing WRF configuration identified in Wootten et al (2016) was used in this study. Some important WRF model options include applying analysis nudging within the outer two domains and using a convective parameterization scheme for the innermost domain to reduce rainfall bias, as discussed in detail within Wootten et al (2016).…”

“…et al, 2014) with significant rainfall reduction, −23%, for RCP8.5 by mid-century with a mean warming of 1.3 C. Finally, the best performing WRF configuration identified in Wootten et al (2016) was used in this study. Some important WRF model options include applying analysis nudging within the outer two domains and using a convective parameterization scheme for the innermost domain to reduce rainfall bias, as discussed in detail within Wootten et al (2016).…”

Optimizing the Weather Research and Forecasting (WRF) Model for Mapping the Near-Surface Wind Resources over the Southernmost Caribbean Islands of Trinidad and Tobago

“…However, only one specific model configuration of a NWP was used in producing Vaisala's global wind maps. NWP studies for the Caribbean region have focused on a NWP's ability and sensitivity in predicting short-term heavy rainfall events in Puerto Rico, Barbados and Guyana [19][20][21] and hurricane evolution and associated storm surge [22][23][24]. Therefore, this study intends to optimize a NWP model output to produce more accurate model winds for one of the Caribbean small island states.…”

High-Resolution Biomass Burning Aerosol Transport Simulations in the Tropics

“…The WRF Double-Moment 6-class microphysics scheme [28] and the Grell 3D Ensemble Scheme Atmosphere 2020, 11, 91 9 of 30 cumulus parameterization scheme [29] are employed for both domains. Previous studies [30][31][32] have demonstrated that the activation of the cumulus parameterization scheme in the inner domain with high resolution improves the precipitation simulations. Since this study focuses on PM10 concentrations near the ground, the performance of the model for simulating near-surface wind fields is important.…”