EVALUATION AND COMPARISON OF MODIS AEROSOL OPTICAL DEPTH RETRIEVAL ALGORITHMS OVER BRAZIL.

Area of Science:

• Atmospheric Science
• Remote Sensing
• Environmental Monitoring

Background:

• Brazil faces substantial aerosol pollution, especially from Amazonian biomass burning, impacting climate and health.
• Accurate Aerosol Optical Depth (AOD) data is crucial for understanding these impacts.

Purpose of the Study:

• To validate and compare satellite-derived AOD products over Brazil.
• To assess the performance of different Moderate Resolution Imaging Spectroradiometer (MODIS) algorithms against ground-based measurements.

Main Methods:

• Utilized 17 sunphotometers from the AErosol RObotic NETwork (AERONET) for ground-based validation.
• Compared MODIS AOD products from Dark Target (DT), Deep Blue (DB), and Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithms.

Main Results:

• High correlation (R>0.9) observed between MODIS AOD products and AERONET data.
• MODIS AOD products showed tendencies to overestimate or underestimate values depending on the algorithm and AOD magnitude.
• Algorithm performance varied with land cover (challenges in Savanna and Urban), view geometry, and aerosol distribution.

Conclusions:

• MAIAC and DB algorithms demonstrated superior stability in retrieving AOD values.
• Caution is advised when applying these satellite AOD products for aerosol mapping in specific environments, particularly urban areas.