Ensemble using different Planetary Boundary Layer schemes in WRF model for wind speed and direction prediction over Apulia region

• Published in: Advances in science and research 2017-04, Vol.14, p.95-102
• Main Authors: Tateo, Andrea, Miglietta, Mario Marcello, Fedele, Francesca, Menegotto, Micaela, Monaco, Alfonso, Bellotti, Roberto
• Format: Article
• Language: English
• Subjects: Aerodynamics; Air quality; Artificial neural networks; Boundary conditions; Boundary layers; Climatology; Computer simulation; Configurations; Economic conditions; Emergency warning programs; Environmental monitoring; Industrial plants; Iron and steel plants; Kalman filters; Mean square errors; Mesoscale phenomena; Meteorological conditions; Meteorological satellites; Microphysics; Neural networks; Nonlinearity; Numerical weather forecasting; Outdoor air quality; Parameterization; Performance enhancement; Planetary boundary layer; Point source pollution; Post-production processing; Prediction models; Radiation; Recovery; Regional planning; Regression analysis; Steels; Surface boundary layer; Surface layers; Topography; Turbulence; Weather forecasting; Wind speed
• ISSN: 1992-0636; 1992-0628; 1992-0636
• DOI: 10.5194/asr-14-95-2017

The Weather Research and Forecasting mesoscale model (WRF) was used to simulate hourly 10 m wind speed and direction over the city of Taranto, Apulia region (south-eastern Italy). This area is characterized by a large industrial complex including the largest European steel plant and is subject to a Regional Air Quality Recovery Plan. This plan constrains industries in the area to reduce by 10 % the mean daily emissions by diffuse and point sources during specific meteorological conditions named wind days. According to the Recovery Plan, the Regional Environmental Agency ARPA-PUGLIA is responsible for forecasting these specific meteorological conditions with 72 h in advance and possibly issue the early warning. In particular, an accurate wind simulation is required. Unfortunately, numerical weather prediction models suffer from errors, especially for what concerns near-surface fields. These errors depend primarily on uncertainties in the initial and boundary conditions provided by global models and secondly on the model formulation, in particular the physical parametrizations used to represent processes such as turbulence, radiation exchange, cumulus and microphysics. In our work, we tried to compensate for the latter limitation by using different Planetary Boundary Layer (PBL) parameterization schemes. Five combinations of PBL and Surface Layer (SL) schemes were considered. Simulations are implemented in a real-time configuration since our intention is to analyze the same configuration implemented by ARPA-PUGLIA for operational runs; the validation is focused over a time range extending from 49 to 72 h with hourly time resolution. The assessment of the performance was computed by comparing the WRF model output with ground data measured at a weather monitoring station in Taranto, near the steel plant. After the analysis of the simulations performed with different PBL schemes, both simple (e.g. average) and more complex post-processing methods (e.g. weighted average, linear and nonlinear regression, and artificial neural network) are adopted to improve the performances with respect to the output of each single setup. The neural network approach comes out as the most promising method.