Diurnal variations of simulated precipitation over East Asia in two regional climate models

Abstract

[1] The diurnal variations of precipitation over East Asia simulated by the National Centers for Environmental Prediction (NCEP) Regional Spectral Model (RSM) and the Weather Research and Forecasting (WRF) model are evaluated during the integration period of June-July-August (JJA) 2006. The models reproduce the observed seasonal mean of large-scale features and precipitation satisfactorily, although the bias patterns differ in both models. The lower tropospheric circulation features are better reproduced by the WRF, while the upper-level circulations closely follow the RSM analysis. Furthermore, the RSM simulated seasonal precipitation is distinctly overestimated over land, whereas the oceanic precipitation is exaggerated by the WRF. However, the characteristics of the diurnal cycle of precipitation simulated by the two models are very similar in many aspects. Both models reproduce an afternoon peak over land and a daybreak peak over oceans. The simulated diurnal and semidiurnal cycles of precipitation amount are also comparable to the corresponding observations. However, the peaks are shifted approximately 2 h ahead. The diurnal variation of the frequency is fairly well simulated, although the semidiurnal variations are poorly resolved. The diurnal and semidiurnal variations of the intensity are not captured by either model. The ensemble mean of the model results does not provide a distinct advantage in appraising the diurnal variation of precipitation. Further physics sensitivity experiments reveal that the cumulus parameterization process influences the modulation of the simulated phase at maximum precipitation over land, whereas the amplitude is more highly controlled by the boundary layer processes.Citation: Koo, M.-S., and S.-Y. Hong (2010), Diurnal variations of simulated precipitation over East Asia in two regional climate models,

Projected Climate Change Scenario over East Asia by a Regional Spectral Model

“…This model has been widely evaluated over East Asia and produced successful results in reproducing summer monsoon precipitation over the region (Yhang and Hong, 2008;Kanamitsu et al, 2010). It has been employed as a useful research tool in understanding precipitation mechanisms embedded within the East Asian monsoon (Kang and Hong, 2008;Koo and Hong, 2010). Figure 1 shows the simulation domain of the RSM, which is the CORDEX East Asian domain with a horizontal grid spacing of approximately 50 km (0.44 degrees).…”

Simulation of Diurnal Rainfall Variability over the Maritime Continent with a High-Resolution Regional Climate Model

“…In general, the literature points toward problems in the boundary layer and convective parameterizations (Wang et al 2007;Koo and Hong 2010), inadequate grid resolution (Lee et al 2007b), error in precipitation generation (Gianotti et al 2012), and error in peak precipitation time as compared with the observations (Joseph et al 2008). Most of these studies involved RCMs and did not make use of high-resolution datasets.…”

“…Wang et al (2007) investigated the effect of lateral convective entrainment-detrainment rates on a simulated diurnal cycle of precipitation. Koo and Hong (2010) investigated diurnal variability and showed that cumulus parameterization modulates the simulated timing of maximum precipitation over land. Qian (2008) simulated the diurnal precipitation cycle over Java, Indonesia and showed that the model was able to reproduce the diurnal cycle, but the simulation was restricted to a single island, and thus the results could not be extended to the rest of the region.…”

“…Relatively few studies over the MC have employed the regional climate model (RCM) (Zhou and Wang 2006;Wang et al 2007;Koo and Hong 2010;Lee et al 2007b). Zhou and Wang (2006) studied geographic effects and the offshore migration of the diurnal cycle of precipitation.…”

Retentivity as an Indicator of the Capacity of Basins without an Outlet to Accumulate Water Surpluses

“…This is not only of hydrological, but also of geomorphological significance, because heavy precipitation moulds (transforms) slopes in the catchments of closed basins [32]. Having a detailed record of the distribution of effective precipitation (measurement every half an hour), it is possible to determine the amount of rainwater that appears on the surface of the catchment at any given time interval and that enters further stages of the water cycle in nature [33].…”