## 3 Results
### Comparison of Atmospheric Parameters
Thus, for the same area of the eastern Black Sea with a size of 33,027 pixels, the statistics of the error flags (data processing quality) were recorded. As in the case of dust transfer on 27.09.2020, the largest number of flags were observed in the LOWLW (13%) and MODGLINT (23%) data. A comparative analysis of the data from the 2 satellites is presented in Table 3 for 2 quality levels. As the third period of dust aerosol transfer over the Black Sea occurred from 25-27 February 2021, where, according to the AERONET data, there was also an increase in the AOT at Section_7 station, low values of the Angstrom parameter and a predominance of coarse-mode atmospheric aerosol were recorded (Figure 8). According to the Ocean Color images, the closest date for comparative analysis was 10.02.2021 due to the absence of clouds over the western part of the Black Sea. A similar analysis was also carried out (as in previous cases) through SeaDas (Figure 9). Figure 8: _Cont._  
Figure 8: (**a**) Variability of the daily AOT values using the AERONET network data on 10.02.2021 and 27.02.2021 for the Section_7_Platform station; (**b**) variability of the daily AOT values using the SPM (Sevastopol) data on 10.02.2021 and 27.02.2021; and (**c**) the 7-day back trajectories on 27.02.2021. Figure 9: _Cont._  
Among the error flags noted on 27.02.2021, the following cases were recorded for STRAYLIGHT, ATMWARM, and TURBIDW, as for the previous dates: AOT recorded by the satellite near the Section_7 station (nearest possible pixels) = 0.25. On 10.02.2021, no error flags were found and the average AOT was 0.04. By analogy, a comparative analysis is presented in Table 4.  
The Rrs(\(\lambda\)) values for the L2 and L3 levels on the days on which the atmosphere was clean (10 February 2021 and 27 February 2021) showed a 99 % correlation. However, when the effect of dust transport on the restoration of the sea brightness coefficients was considered (correlation between the day on which the atmosphere was clean and the atmosphere was dusty), the coefficient dropped to 53% for L3. On 27 February 2021, in situ AERONET Ocean Color measurements of the normalized water-leaving radiance (Lwn) for the Section_7 station were also recorded. The correlation between the in situ measurements recorded on 27 February 2021 and 10 February 2021 was 98%, which indicates the spectrum had the same shape and the close order of the values (Table 5). \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **10.02.2021** & \multicolumn{2}{c}{**27.02.2021**} \\ \hline  & **Quality\_L3** & **Quality\_L2** & **Quality\_L3** \\ \hline Rrs (411 nm) & 0.0018 & \(-\)0.002 & \(-\)0.0021 \\ Rrs (445 nm) & 0.0034 & 0.00087 & 0.00076 \\ \hline Rrs (489 nm) & 0.0042 & 0.0026 & 0.0025 \\ Rrs (556 nm) & 0.0028 & 0.0029 & 0.0027 \\ Rrs (667 nm) & 0.0004 & 0.0006 & 0.0005 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Statistics and average values of Rrs(\(\lambda\)) for the pixels of the selected area of the Black Sea water area of Ocean color products for the day on which dust transfer occurred on 10.02.2021 and 28.02.2021 according to the VIIRS satellite data. Figure 9: Satellite images of VIIRS for the day on which dust transfer occurred on 27 February 2021 and 10 February 2021 (**a**) with a clean atmosphere and (**b**) the spatial variability of the AOT values (source: SeaDas). On 27 February 2021, dust was mainly concentrated in the central part of the Black Sea, where, according to the VIIRS results, the AOT and Angstrom parameter values increased to 0.274 and 0.684, respectively. According to the SPM measurements recorded on 26 and 27 February, increases relative to the monthly average AOT values were observed in all spectral ranges of the device. So, for example, AOT (500) on 26 February was 0.43, and AOT (500) on 26 February was 0.28, which is 1.7 times greater than the monthly average value of AOT (500) of 0.16.