The Role of Unresolved Clouds on Short-Range Global Horizontal Irradiance Predictability

Abstract

The shortwave radiative impacts of unresolved cumulus clouds are investigated using 6-h ensemble simulations performed with the WRF-Solar Model and high-quality observations over the contiguous United States for a 1-yr period. The ensembles use the stochastic kinetic energy backscatter scheme (SKEBS) to account for implicit model uncertainty. Results indicate that parameterizing the radiative effects of both deep and shallow cumulus clouds is necessary to largely reduce (55%) a systematic overprediction of the global horizontal irradiance. Accounting for the model’s effective resolution is necessary to mitigate the underdispersive nature of the ensemble and provide meaningful quantification of the short-range prediction uncertainties.

Assessment of Simulated Solar Irradiance on Days of High Intermittency Using WRF-Solar

“…Similarly, WRF-Solar simulations in 2017 in Kuwait produced RMSEs in GHI and DNI of 101Wm −2 and 137 Wm −2 , respectively [44]. Despite regional weather events dominating error statistics, results from WRF-Solar simulations in other countries show the consensus on misrepresentation of clouds and aerosols has not been fully resolved, but has improved from native WRF simulations [36][37][38]41,[43][44][45].…”

“…All these changes have been incorporated in a specific augmentation of the advanced research version of the WRF Model [35] designed for solar energy predictions known as WRF-Solar [36]. WRF-Solar has been extensively tested in the USA [36][37][38][39][40][41] and other countries, such as Spain [42], Singapore [43], Kuwait [44], and Saudi Arabia [45]. Most studies have reported significant improvements in solar irradiance predictions under different sky conditions with WRF-Solar in comparison to standard WRF simulations.…”

Quantifying feedbacks in the plant-atmosphere-cloud continuum

“…Finally, and in relation to the transfer of our results to large-scale model, numerical weather prediction models generally account for the cloud shading effects through a decrease in shortwave radiation (i.e., our DOMAIN case) (Jiménez et al, 2016).…”

“…However, biases are present in the global horizontal irradiance (Jiménez et al, 2016; Fig. 4b therein).…”

On the interactions between clouds, radiation, turbulence and vegetation in the atmospheric boundary layer

“…Regarding models in which turbulence and moist convection are parameterized, i.e. mesoscale models, Jimenez et al (2016a) studied the radiative effects of parameterized shallow convection at 9 km horizontal resolution using the mesoscale Weather and Research Forecasting model -Solar (WRF-Solar) (Skamarock et al, 2008;Jimenez et al, 2016b). They used two mass-flux type shallow convective parameterizations, namely those of Deng et al (2003Deng et al ( , 2014 and Grell and Freitas (2014).…”