## 3 Discussion Results at the Hemispheric Scale
### Deposition of Mineral Dust in March 2014  
Dust deposition fluxes are larger over the Atlantic Ocean compared to the Pacific Ocean due to higher concentrations over the Atlantic, except over mid latitude over Pacific between 30 and 50\({}^{\circ}\) N. On the Northern Hemisphere, the dry deposition simulated by CHIMERE dominates the total deposition (Figure S11 in Supplementary Materials), while global models generally overestimate the role of wet deposition as described in [94]. The total monthly averaged deposition fluxes (wet and dry) are in line with those reported in the literature [105] presented on a yearly basis even if the range of model results can vary within an order of magnitude due to differences in dust emissions and the parameterization of processes. A ratio \(\Omega\) for the dry (d) and wet (w) deposition processes at a given latitude (_lat_) defined in the set of Equation (2), as the ratio of scavenging coefficients in the _coarse_ (defined here as particle diameter in the range 2.5-40 \(\upmu\)m) over scavenging coefficient in the _fine_ fraction of dust (particle diameter below 2.5 \(\upmu\)m):  
Figure 7: Monthly mean latitudinal cross sections (Altitude a.g.l. versus Latitude \({}^{\circ}\) N) for several variables in March 2014 simulated by CHIMERE for two areas encompassing the Atlantic (80\({}^{\circ}\) W–17\({}^{\circ}\) W) and the Pacific (122\({}^{\circ}\) E–124\({}^{\circ}\) W) Ocean areas. **Top panels** display the mean dust concentrations with bold dashed lines representing the fine fraction of total dust (%), the grey dotted lines are the average zonal winds (conventionally, westerly wind are positive). **Bottom charts** display the evolution of various parameters along the corresponding cross sections and spatially averaged over the longitude: the boundary layer (BL) height in km, the total precipitation (convective and large scale) in cm month\({}^{-1}\), the deep convection updraft flux summed over the column in \(\mathrm{g}_{\mathrm{air}}\) m\({}^{-2}\) s\({}^{-1}\), the mean cloud water content averaged over the first 10 model layers (approximately 2500 m), the wet and dry deposition fluxes of dust sum over time (monthly) in \(\mathrm{mg}_{\mathrm{dust}}\) m\({}^{-2}\) month\({}^{-1}\) and the ratio \(\Omega\) (unit less) of dry (d) and wet (w) scavenging coefficients coarse versus fine particles as defined in Equation (2). \[\overline{C^{\text{col,lat}}_{\text{mode}}(\text{day})}=\frac{\sum_{\text{ver=1}}^{ \text{H}_{\text{top}}}\sum_{\text{l=0}=1}^{\text{Nlon}}\sum_{\text{hour=1}}^{24} \text{C}_{\text{mode}}(\text{hour,lon,lat,ver})\times\Delta\text{H}(\text{ver})}{ \text{H}_{\text{top}}\times\text{Nlon}\times 24}\]  
\[\overline{C^{\text{ground,lat}}_{\text{mode}}(\text{day})}=\frac{\sum_{\text{ lon=1}}^{\text{Nlon}}\sum_{\text{hour=1}}^{24}\text{C}_{\text{mode}}(\text{hour,lon,lat,1})}{ \text{Nlon}\times 24}\]  
\[\text{mode}=\"\text{fine}\"(\varphi<2.5\ \upmu\text{m})\text{ or }\"\text{coarse}\"(2.5\ \upmu\text{m}<\varphi<20\ \upmu\text{m})\]  
\[\overline{\text{D}_{\text{dep,mode,lat}}(\text{day})}=\frac{\sum_{\text{lon=1 }}^{\text{Nlon}}\sum_{\text{hour=1}}^{24}\text{D}_{\text{dep,mode}}(\text{ hour,lon})}{\text{Nlon}\times 24} \tag{2}\]  
\[\text{dep}=\"\text{w}\"\text{ or }\"\text{or }\"\  
\[C_{BL\text{ }or\text{ }FT}\Big{[}\text{mg}\,\text{m}^{-2}\Big{]}=\sum_{h=BL\text{ }or\text{ }FT}\Bigg{(}\sum_{time}C\Big{[}\text{\mu g}\,\text{m}^{-3}\Big{]}\times\Delta h [\text{m}]/1000\Bigg{)} \tag{3}\]  
\[Ratio\,\left(\%\right)=C_{FT}\Big{[}\text{mg}\,\text{m}^{-2}\Big{]}\,/\left(C_{ FT}\Big{[}\text{mg}\,\text{m}^{-2}\Big{]}+C_{BL}\Big{[}\text{mg}\,\text{m}^{-2} \Big{]}\right) \tag{4}\]  
Figure 8 reveals the transport of dust over the Northern Hemisphere. Figures S7-S10 in Supplementary Materials provide the full daily evolution of the concentrations in March 2014. A more spread structure in the FT is observed with a shift towards the northeast compared to the concentrations within the BL.