MAD-WRF for Solar Irradiance Nowcasting

This presentation will provide an overview of the MAD-WRF model. MAD-WRF is an improved end-to-end solar irradiance forecast system that combines the Multi-Advection and Diffusion Nowcast (MADCast) philosophy of using a satellite-based initialization and WRF to advect and diffuse microphysics quantities, with the physics of the WRF-Solar NWP model. The MAD-WRF cloud initialization is based on observations of the cloud base / top height combined with a cloud initialization parameterization. The parameterization relies on relative humidity to identify the location of clouds and estimate the liquid water and ice content. If hydrometeors are available at initialization time, the parameterization builds on the hydrometeors fields to further enhance the initial cloud field. The performance of the initialization is enhanced by assisting the cloud identification scheme with cloud base / top height observations. The benefits of using cloud top height retrievals from GOES16 and cloud base height observations from METAR stations are investigated. Results are compared against global horizontal irradiance observations from the SURFRAD network and illustrate the added value of the MAD-WRF nowcasting system.