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This study evaluates historical simulation of solar photovoltaic potential (PVpot) during 1989–2008 over China against the ERA5 reanalysis, using the Weather Research and Forecasting (WRF) model and Regional Climate Model version 4 (RegCM4) within the framework of the Coordinated Regional Downscaling Experiment-East Asia second phase (CORDEX-EA-II). The impacts of spectral nudging technique and land surface model on the simulated PVpot are investigated as well. Results indicate that the observed PVpot is abundant over western China, which can reach up to 26% in summer particularly. The WRF simulations significantly overestimate the PVpot over most areas of China, with the bias about 9% over southeastern China, while the utilization of spectral nudging method and CLM4 land surface model can greatly reduce the deviation. The RegCM4 simulations generate underestimation of PVpot over Northwest China and overestimation over Southeast China. As for the interannual variation, the observed PVpot features an increase of 0.9%/decade over southeastern China. The WRF and RegCM4 simulations can reproduce the rising trend of PVpot, while the magnitude is much lower than ERA5. The WRF simulations can properly portray the characteristics of seasonal cycle of PVpot, with the peaks in May over entire China and most subregions, while RegCM4 exhibits poor skill in reproducing the intra-annual variation. Moreover, the simulated bias in the clear-sky solar radiation (RSDSCS), low-level cloud fraction, and light rain during the daylight may contribute to the deficiency of PVpot. [ABSTRACT FROM AUTHOR]

Under the Coordinated Regional Downscaling Experiment‐East Asia second phase (CORDEX‐EA‐II) framework, the performances of three regional climate models (RCMs), including Weather Research and Forecasting (WRF) model, RegCM4 and Consortium for Small‐Scale Modelling model in Climate Mode (CCLM), in simulating the climatic distribution, diurnal variation and extremes of precipitation during 1989–2009 are evaluated. The RCMs are driven by the ERA‐Interim reanalysis and the evaluation is based on both the gridded gauge‐based and the satellite‐derived precipitation data. In general, the RCMs can reproduce the spatial pattern of the mean daily precipitation, with the spatial correlations (SCORs) larger than 0.66, and CCLM has the lowest root‐mean‐square error over East Asia. For the diurnal cycle of precipitation, WRF outperforms the other two RCMs despite the peak time about 3 hr ahead in some areas. RegCM4 overestimates the amplitude of the diurnal curve, and CCLM has limited ability to simulate the diurnal variation over most areas. All the three RCMs can reproduce the spatial patterns of the extreme indices, with the SCORs larger than 0.57. WRF and CCLM perform the best for the frequency of wet days (R1mm) and moderate rain (R20mm), respectively. The intensity indices are overestimated over most land areas, with relatively higher SCORs in WRF and relatively lower biases in RegCM4. The consecutive wet days (CWD) can be well simulated by WRF and CCLM; however, RegCM4 overestimates it over most regions in East Asia. The overestimation of the extreme intensity and frequency indices may be related to the higher water vapour content and the weaker water vapour divergence in the lower layer, as well as the higher mid‐layer geopotential height, especially in CCLM. [ABSTRACT FROM AUTHOR]

Based on an object‐based tracking (OT) algorithm, the precipitation systems in the convection‐permitting (CP, ∼4 km) regional climate model (RCM) are evaluated from the Lagrangian viewpoints. The characteristics of precipitation systems over eastern China during 1998–2007 derived from the CP RCM are compared with the satellite‐derived precipitation data set CMORPH. It is found that, with the cumulus parameterization switched off and reasonable representation of complex terrain, the precipitation systems in the CP RCM can propagate in the same direction as observation, but CP RCM tends to under‐/overpredict the precipitation systems with slow/fast propagation speed. Nevertheless, CP RCM can reasonably capture the average duration and eccentricity of all precipitation systems. The major deficiency in CP RCM is that the simulated precipitation systems are significantly weaker with larger coverage area. Over‐/underrepresentation of precipitation systems driven by large‐scale circulations/intense thunderstorms in CP RCM leads to wet and dry biases in the total precipitation of the longer‐duration (≥48 hr) and shorter‐duration (<48 hr) systems, respectively. It is suggested that assessment of the lifecycles of propagating precipitation systems in the Lagrangian framework is complementary to the traditional point‐to‐point Eulerian validation method. Key Points: Precipitation systems in long‐term convection‐permitting simulation over eastern China are assessed in the Lagrangian frameworkConvection‐permitting simulation captures the duration, eccentricity, and propagation direction of the tracked systems wellConvection‐permitting simulation over‐/under‐represents systems dynamically/thermally driven by large‐scale circulations/thunderstorms [ABSTRACT FROM AUTHOR]

Based on the Coordinated Regional Downscaling Experiment‐East Asia second phase (CORDEX‐EA‐II) with higher resolution, model results driven by ERA‐Interim reanalysis using WRF, RegCM4 and CCLM are evaluated against the observational datasets including CN05.1, CRU and GPCP during the period of 1989–2009. The results show that the RCMs have the capability to simulate the annual and seasonal mean surface air temperature and precipitation, however, some biases are produced. The biases are highly dependent on the geophysical locations and the RCMs applied, and CCLM agrees better with the observed precipitation over ocean. CCLM also outperforms the other two RCMs in simulating the interannual variations of temperature and precipitation in most sub‐regions, which can be attributed to its better presentation of the interannual variation of large scale circulation. Generally, all the three RCMs can well reproduce the seasonal cycles of the surface air temperature in most sub‐regions, however, only in the northern regions of China can the RCMs well reproduce the seasonal cycles of precipitation. [ABSTRACT FROM AUTHOR]

With a six‐year (2009–2014) summer climate simulation using the Weather Research and Forecasting model at convection‐permitting resolution (4‐km grid spacing), the effects of microphysics parameterization (MP) schemes on precipitation characteristics are investigated in this study. The convection‐permitting simulations employ three popular MP schemes, namely, Lin (single‐moment bulk MP), Weather Research and Forecasting Single‐Moment 5‐class (one‐moment and mixed‐phased MP), and Thompson (two‐moment and mixed‐phase MP) scheme. By evaluating the simulations against the CMORPH, rain gauge (Station), and ERA‐Interim data, it is found that the convection‐permitting model reproduce well the summer precipitation amount and the associated large‐scale atmospheric circulations, which are insensitive to the choice of MP schemes. The simulations with three MP schemes overestimate the precipitation amount, especially over the Yangtze‐Huaihe River Valley. The overestimations may be due to the systematic biases, and cannot be significantly reduced by using different MP schemes. Moreover, all simulations capture well the major features of precipitation diurnal variations and their transition characteristics, but they significantly overestimate the precipitation frequency while underestimate the precipitation intensity. The analysis on the microphysical hydrometeors shows that the model‐simulated precipitation amount is considerably affected by the vertical profiles of solid hydrometeors, especially the snow and graupel particles. The Thompson scheme creates more snow particles and less graupel than the other schemes, while produces the least precipitation amount that best matches the CMORPH. Key Points: Large‐scale atmospheric circulations are insensitive to the microphysics parameterizations, which do not significantly reduce the systematic biasesConvection‐permitting simulations can capture the major precipitation diurnal variations and transition characteristicsThe vertical profiles of solid hydrometeors, especially the snow and graupel particles, play important roles in precipitation amount simulations [ABSTRACT FROM AUTHOR]

Through soil moisture-temperature feedback, soil moisture significantly impacts heatwaves, which have detrimental effects on ecosystems, society, and human health. This study analyzed the spatiotemporal features of heatwave indices, including heatwave magnitude (HWM) and frequency (HWF) over eastern China during 1998–2010, and their relationships with antecedent soil moisture based on both observations and model simulations. To reasonably capture the land-atmosphere feedback, the convection-permitting (4 km grid spacing) Weather Research and Forecast model (WRF_CPM) was adopted for the investigation. Results show that WRF_CPM can reasonably simulate the observed spatial and temporal features of heatwave indices over most of the six chosen subregions of eastern China, except HWM in Jiangnan Hills (JNH). As a good indicator of soil moisture anomaly (SMA), the standardized precipitation evapotranspiration index (SPEI) was applied to illustrate the soil moisture-heatwave relationship. SPEI is negatively correlated with both HWF and HWM over JNH, Yangtze-Huai River basin (YHR), Sichuan Basin (SCB), and North China Plain (NCP). Such negative correlations are well reproduced by WRF_CPM, except for HWM in southeast China and HWF in NCP. It is indicated that increased soil moisture suppresses HWM in most areas, especially for the high quantiles, and such relationship is pronounced in YHR, JNH, NCP, Loess Plateau (LP), and SCB. Similarly, HWF was more dependent on SPEI for the higher quantiles, especially in YHR, JNH, SCB, and NCP. WRF can well capture the heterogeneous responses of heatwave indices to antecedent SPEI over most subregions except for underestimate the high-quantile HWF responses in NCP, and slightly overestimate HWF responses in JNH, respectively. The relationship between SPEI and soil moisture is consistent with the theoretical considerations. Additionally, the results illustrate the advantages of a high-resolution (4 km) convection-permitting model in simulating the impacts of antecedent soil moisture on heatwaves in China, which are also important implications for land-atmosphere coupling research as well as heatwave monitoring and forecasting. • The convection-permitting regional model well simulate heatwave features and their relationship with soil moisture. • The impacts of antecedent soil moisture on frequency and magnitude of heatwaves are stronger at higher quantiles. • Soil moisture have different behavior in modulating heatwaves in subregions over eastern China. • The standardized precipitation evapotranspiration index could reasonably represent soil moisture anomaly. [ABSTRACT FROM AUTHOR]

In this study, the extreme temperature in high-resolution hindcast simulations conducted by three reanalysis-driven regional climate models (WRF, RegCM4 and CCLM) is evaluated during the period of 1989–2009. We select 10 extreme temperature indices recommended by the Expert Team on Climate Change Detection and Indices to compare the simulations with the CN05.1 dataset. In addition, apparent temperature (AT) combining relative humidity and air temperature is applied to define the humid heat wave indices. The results show that the regional climate models (RCMs) can skillfully reproduce the spatial distribution and the probability density function of daily maximum temperature (Tmax) and minimum temperature (Tmin) in spite of some biases in certain ranges and regions. For the intensity indices (TXx, TNn, TXn, TNx), the RCMs demonstrate very high spatial correlations with the observation, but they have difficulties in reproducing the interannual variations of these indices. CCLM best simulates the interannual variabilities of the percentile-based indices, while WRF shows better skill in reproducing their spatial patterns (TX10p, TX90p). In regard to the duration indices, RegCM4 outperforms WRF and CCLM in simulating the consecutive cold events (CSDI), while WRF performs best for the continuous hot days (WSDI). The humid heat wave, which is characterized by both high temperature and humidity, is skillfully reproduced by the RCMs as well. The overestimation of the magnitude and intensity of humid heat waves in WRF can be attributed to the favorable large-scale circulation and water vapor condition. • WRF and RegCM4 tend to underestimate Tmax and Tmin, while CCLM exhibits warm bias of Tmin in large areas of China. • The RCMs can capture extreme hot events more skillfully than extreme cold events. • CCLM shows superior ability in reproducing the interannual variations of extreme temperature. • The biased properties of humid heat wave in the RCMs are attributed to the anomalous large-scale circulations. [ABSTRACT FROM AUTHOR]