Temporal and Spatial Assessment of Aerosol Optical Depths in Tizi-Ouzou, Algeria, Using Aqua-MODIS Product

In this study, we conducted a detailed analysis of the atmospheric aerosols distribution in the Tizi-Ouzou region, located in northern Algeria, using data from the Aqua-MODIS (MYD04). Our main objective was to evaluate the aerosol optical depths (AOD) over a six-year period from 2012 to 2017.To achieve this, we utilized three specific MODIS products based on three algorithms: Deep Blue (DB), Dark Target (DT), and Deep Blue-Dark Target Combined (DB-DT). These algorithms allowed us to retrieve AOD data at a wavelength of 550 nm. We compared these AOD estimations with measurements from the RESA_LAMPA station based in our laboratory, which is part of the Aerosol Robotic Network (AERONET). The evaluation of the results involved calculating correlations between MODIS AOD estimations and AERONET AOD measurements. We considered different temporal windows (±15, ±30, ±60 min) and spatial windows (3, 15, 25, 50 km) to analyze the performance of the Aqua- MODIS products under various configurations. The optimal chosen temporal window was ±60 min, and the spatial window was 25 km. The results showed significant correlations between MODIS AOD estimations and AERONET AOD measurements. Specifically, we obtained high correlation coefficients for the DT algorithm (R = 0.89), DB-DT algorithm (R = 0.90), and DB algorithm (R = 0.80). These findings indicate that the DB, DT, and DB-DT algorithms of MODIS are capable of providing reliable estimations of aerosol optical depths in the Tizi-Ouzou region. Moreover, we found that the Dark Target and DB-DT combined algorithm, with a temporal window of ±60 min and a spatial window of 25 km, appears to be the most suitable for estimating aerosol optical depths in the region from 2012 to 2017. Our study provides valuable insights into the distribution of atmospheric aerosols in the Tizi-Ouzou region using Aqua-MODIS data. These results contribute to a better understanding of the optical properties of aerosols in this region and can be utilized for further studies on air quality and the effects of aerosols on climate and human health.