## 2 Experiments
### Observational Data for the Evaluation of Model Performances
Dates of passes and approximate hour (YYYYMMDD HH:MM UTC) for each cases: CAR1: 20140305 15:00; CAR2: 20140306 07:00; CAR3: 20140324 05:00; CAR4: 20140325 04:00; CAR5: 20140327 04:00; CAR6: 20140330 04:00; CAS1: 20140316 10:00; CAS2: 20140318 10:00; CAS3: 20140319 21:00; CAS4: 20140320 20:00; CAS5: 20140320 20:00 (same pass as CAS4); CAS6: 20140330 22:00; CNA1: 20140313 18:00; CNA2: 20140314 05:00; CNA3: 20140316 19:00; CNA4: 20140317 18:00; CNA5: 20140327 19:00; CNA6: 20140328 06:00; EUR1: 20140310 03:00; EUR2: 20140310 14:00; EUR3: 20140312 14:00; EUR4: 20140330 03:00; EUR5: 20140331 13:00; NAM1: 20140312 20:00; NAM2: 20140316 09:00; NAM3: 20140318 09:00; NAM4: 20140327 20:00; PAC1: 20140319 13:00; PAC2: 20140319 14:00. * Air quality data from the US EPA (Environmental Protection Agency) network provides hourly PM\({}_{2.5}\) concentrations accessible at [[https://www.epa.gov/outdoor-air-quality-data](https://www.epa.gov/outdoor-air-quality-data)]([https://www.epa.gov/outdoor-air-quality-data](https://www.epa.gov/outdoor-air-quality-data)). * Data from the Chinese network provides hourly PM\({}_{10}\) and PM\({}_{2.5}\) concentrations made available for the Beijing area. * The French GEOD'AIR database provides PM\({}_{10}\) and PM\({}_{2.5}\) concentrations for some stations over the French Caribbean Islands in this study (Available online: [[https://www.geodair.fr/](https://www.geodair.fr/)]([https://www.geodair.fr/](https://www.geodair.fr/))). * For the whole Europe, background PM\({}_{2.5}\), PM\({}_{10}\) and Calcium daily and/or hourly data are retrieved thanks to the EMEP-EBAS database [83]. As a first estimate, Soil PM can be calculated as a first guess from calcium measurements by multiplying the calcium concentrations by a factor of 8 [84]. * The modeled daytime Aerosol Optical Depth (AOD) is compared to observations from the AERONET network [85], available at [[https://aeronet.gsfc.nasa.gov](https://aeronet.gsfc.nasa.gov)]([https://aeronet.gsfc.nasa.gov](https://aeronet.gsfc.nasa.gov)) from the daily AERONET level-2 measurements AERONET-AOD at 870 nm. Unfortunately, AERONET measurements can be used in clear sky conditions areas generally below 20\({}^{\circ}\) N in latitude over the Northern Hemisphere, while the model can simulate the AOD for all types of sky. For Europe [86], Central Asia or North America, most dust outbreaks are issued from low-pressure systems and then imply cloudy conditions that makes impossible to use level 2 AERONET products to detect these episodes since most of data are ruled out due to clouds. * Synoptic data called SYNOP from the World Meteorological Organization (WMO) provide reporting weather observations made by manned and automated weather stations. The following ten types of coded data have been selected to identify observed dust episodes: \"widespread dust in suspension not raised by wind\", \"dust or sand raised by wind\", \"well developed dust or sand whirls\", \"dust or sand storm within sight but not at station\", \"slight to moderate dust storm decreasing in intensity\", \"slight to moderate dust storm, no change\", \"slight to moderate dust storm, increasing in intensity\", \"severe dust storm, decreasing in intensity\", \"severe dust storm, no change\", and \"severe dust storm, increasing in intensity\". The categories \"Haze\" and \"Smoke\" have not been considered. These observations remain subjective as they are man-based observations: they can be mixed-up with anthropogenic, wildfires pollution, or misty and foggy conditions, but, in some locations, such as in Central Asia, this information is the only one we can access. * Additional data from isolated stations or issued from previous publications will be used to assess the model performances. Maps of site locations of interest and discussed in this study are provided in Figure S6 in the Supplementary Materials.