## 3 Results
### Comparison of Satellite and In Situ AOT
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**12.09.2017**} & \multicolumn{2}{c}{**08.09.2017**} \\ \hline  & **Quality\_L2** & **Quality\_L3** & **Quality\_L2** & **Quality\_L3** \\ \hline Pixels & 173,182 & 161,908 & 166,865 & 156,545 \\ AOT(869) & 0.161 & 0.157 & 0.034 & 0.033 \\ Angstrom & 1.393 & 1.410 & 1.673 & 1.67 \\ \hline Rrs (412 nm) & \(-\)0.0002 & \(-\)0.00005 & 0.0031 & 0.0032 \\ Rrs (443 nm) & 0.00204 & 0.00211 & 0.0040 & 0.0041 \\ \hline Rrs (469 nm) & 0.0033 & 0.003364 & 0.0046 & 0.0046 \\ Rrs (488 nm) & 0.0036 & 0.003645 & 0.0049 & 0.0049 \\ Rrs (531 nm) & 0.0030 & 0.003009 & 0.0039 & 0.0038 \\ Rrs (547 nm) & 0.0026 & 0.002664 & 0.0034 & 0.0034 \\ Rrs (555 nm) & 0.0023 & 0.002287 & 0.0030 & 0.0030 \\ Rrs (645 nm) & 0.0002 & 0.0002 & 0.0004 & 0.0004 \\ Rrs (667 nm) & 0.0002 & 0.0002 & 0.0003 & 0.0003 \\ Rrs (678 nm) & 0.0002 & 0.0002 & 0.0004 & 0.0004 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Statistics and average values for the pixels of ocean color products on the day of dust transfer on 12 September 2017 and to 8 September 2017 for the eastern part of the Black Sea according to MODIS Aqua satellite data. day on which dust transfer occurred. For the convenience of analysis of the spectra of the brightness coefficient, we visualized the calculations according to Table 1.  
From Figure 3, it follows that with dust, even with the maximum pixel quality (Quality_L3), Rrs(\(\lambda\)) in the short-wavelength region showed a negative value. This once again proves the incorrect operation of the atmospheric correction algorithms. Moreover, Rrs(\(\lambda\)) on the day on which the atmosphere was clean was 20% higher than when dust aerosols were present (Figure 3). The correlation coefficient between the values of the remote sensing reflectance for days on which the atmosphere was clear and for days on which dust was present was calculated by the following formula:  
\[Correl(X,Y)=\frac{\sum(x-\overline{x})(y-\overline{y})}{\sqrt{\sum(x-\overline {x})^{2}\sum(y-\overline{y})^{2}}}\]  
Figure 3: Spectral distribution of the average Rrs(\(\lambda\)) values according to MODIS (Aqua) data for 12.09.2017 and 08.09.2017 depending on the error flags. where \(\overline{x}\) and \(\overline{y}\) are the sample mean (in our case, for Rrs(\(\lambda\))). Thus, the correlation of Rrs(\(\lambda\)) for L2 was 83%, and for L3, it was 84%. This confirms that an error of 16-17% was caused by the contribution of dust. In the second stage of this study, analysis of the correlation between satellite and in situ measurement data (AERONET, portable spectrophotometer SPM) was carried out for the western part of the Black Sea, since the dust transfer that occurred on 12.09.2017 also affected it. A comparative analysis of the optical characteristics of the two dates for the AERONET Galata_Platform station is shown in Figure 4. Figure 4 shows the temporal variability of the daily AOT on 08.09.2017 and 12.09.2017. Figure 4 also demonstrates the spectral course of AOT according to the results from the SPM spectrophotometer measurements over Sevastopol on the investigated dates. From Figure 4, it follows that even with the maximum correction of the Cimel-318 data (level 2) on the day on which dust transfer occurred, the AOT values were more than 1.5 times higher than the monthly average values on 08.09.2017. Moreover, the advantages of the day on which coarse aerosol fraction was present in the atmosphere, 12 September 2017, are indicated by the low Angstrom parameter values: \(\alpha=0.67\), with a monthly average value for September of \(\alpha=1.415\). A similar situation was observed for the Gloria station. Unfortunately, on the day on which dust transfer occurred, none of the coastal Black Sea stations recorded corresponding satellite values. Thus, we decided to search for the points  
Figure 4: Spectral variability of AOT values according to the AERONET network data on 08.09.2017 and 12.09.2017 for the Galata_Platform station (**a**) and for the SPM spectrophotometer over Sevastopol (**b**).