Evaluation of WRF-CHEM model against data during a high PM10 episode in Southern Italy

In this study, the Weather Research and Forecasting model with online coupled chemistry (WRF-Chem) is applied to simulate an intense Saharan dust outbreak event that took place over the Southern Italy in March 2016. The WRF model is found to reproduce well the synoptic meteorological conditions driving the dust outbreak: an omegalike pressure configuration associated with a weak cyclogenesis in the Iberian Peninsula. At the end of the simulated period the merging of two minima produce a large depression in the Peninsular Italy. The model performances in reproducing the atmospheric desert dust load is evaluated using a multi-platform observational dataset of aerosol and desert dust properties, including optical properties from satellite and ground-based sun-photometers, plus in-situ particulate matter mass concentration (PM) data. This comparison allows us to investigate the model ability in reproducing both the horizontal and the vertical displacement of the dust plume, and its evolution in time. The preliminary comparison with satellite (MODIS-AQUA) and sunphotometers (AERONET) showed that the model is able to reproduce well the horizontal field of the aerosol optical depth (AOD) and its evolution in time. The routinely measurements of ARPA-Puglia revealed the intense dust outbreak with peak PM10 value larger than 300 µg/m3 during march 23. On the other side, the model-measurements comparison for PM10 shows a good temporal matching. The model-to-measurements comparisons allows the evaluation and the tuning of physics-based emission scheme that is part of the WRF-Chem package release.