# First Lidar Campaign in the Industrial Sites of Volta Redonda-RJ and Lorena-SP, Brazil
## 4 Data Retrieval and Results
### Volta Redonda and Lorena Campaigns
The HYSPLIT air-mass back trajectories in Figure 7 show the plumes detected around 3000 m a.g.l. of altitude by the lidar system. They come directly from several fire focuses spread all over the central portion of South America. According to the active fire database from The National Institute for Space Research (INPE), which relies on information extracted at 1000 m resolution from daily AQUA MODIS data available at [[https://worldview.earthdata.nasa.gov/](https://worldview.earthdata.nasa.gov/)]([https://worldview.earthdata.nasa.gov/](https://worldview.earthdata.nasa.gov/)) (accessed on 17 September 2021) and other satellites available at [[https://queimadas.dgi.inpe.br/](https://queimadas.dgi.inpe.br/)]([https://queimadas.dgi.inpe.br/](https://queimadas.dgi.inpe.br/)) (accessed on 17 September 2021), there were more than 953 focuses of fire in the period of 22-26 June 2014 in the South America territory. The daily average backscatter profiles are presented in Figure 8 for the same days. The averages were done in the following way. First, we separated the range corrected signals in periods of 1 h. Then, we averaged the signals within the selected period in order to estimate the aerosol backscatter profile for the corresponding period. For this, a scan over the altitude of the region used to obtain the molecular fit was performed and the best one was chosen. Notice that, with this procedure, the altitude range of the molecular fit can be different for each time period during the day, reflecting the dynamics of the atmosphere. Finally, the aerosol backscatter profiles were averaged over the different time periods. The band corresponds to the uncertainty on the backscatter coefficient obtained by assuming different lidar ratio values corresponding to 68% C.L. of the measurement performed by the CALIPSO satellite. As commented before, we can see high magnitude values of \(\beta_{aer}\) on 4 June for altitude \(\sim\)500 m. Notice that the backscatter coefficient for the referred day was multiplied by 0.25 in order to keep the same scale for all different days. Besides, the other analyzed days present large dispersion of the aerosol content with the boundary layer reaching altitudes of \(\sim\)2000 m a.g.l. Figure 6: Aerosol backscatter profiles for three representative measurement days in Lorena city: (**a**) Clean day; (**b**) day with possible transport of aerosols; and (**c**) polluted day. Unfortunately, during the measurement campaign employed in Volta Redonda, the weather conditions were not favorable for aerosol lidar measurements, with the occurrence of long periods of cloud covered sky or heavy rain. For this reason, we present only the results related to 4 December 2018. Figure 9 presents the corresponding image of the aerosol backscatter profiles obtained in time bins of 100 s for the whole measurement period. The white color corresponds to non-physical negative values of the aerosol backscatter coefficient caused by a poor quality lidar retrieval due to a noisy signal in some time periods. The aerosol boundary layer is not clearly defined, possibly because it is below the overlap region of the detector, since the measurement was performed during the night. The high magnitude values of \(\beta_{aer}\) present from \(\sim\)23:00 to \(\sim\)02:00 were considered to be originated by clouds and were discarded for the daily average backscatter profile, which will be presented later. We can notice a very dirty atmosphere with aerosol content present essentially at the whole range of altitudes considered, especially at altitudes between 1000 m and 2500 m a.g.l. It is noteworthy to mention that the measurements were taken very close to the CSN, as detailed in Figure 1c.