MIL3MAE_4 is the Multi-angle Imaging SpectroRadiometer (MISR) Level 3 Component Global Aerosol Product covering a month version 4. It contains a statistical summary of column aerosol 555-nanometer optical depth and a monthly aerosol compositional type frequency histogram. This data product is a global summary of relevant Level 2 aerosol parameters, averaged over a month and reported on a geographic grid with a resolution of 0.5 degrees by 0.5 degrees. The collection for this product was completed in May of 2017.

The MISR instrument consists of nine push-broom cameras that measure radiance in four spectral bands. Global coverage is achieved in nine days. The cameras are arranged with one camera pointing toward the nadir, four forward, and four aftward. It takes seven minutes for all nine cameras to view the same surface location. The view angles relative to the surface reference ellipsoid are 0, 26.1, 45.6, 60.0, and 70.5 degrees. The spectral band shapes are nominally Gaussian, centered at 443, 555, 670, and 865 nm.

MISR is designed to view Earth with cameras pointed in 9 different directions. As the instrument flies overhead, each piece of Earth's surface below is successfully imaged by all nine cameras in 4 wavelengths (blue, green, red, and near-infrared). The goal of MISR is to improve our understanding of the effects of sunlight on Earth and distinguish different types of clouds, particles, and surfaces. Specifically, MISR monitors the monthly, seasonal, and long-term trends in three areas: 1) amount and type of atmospheric particles (aerosols), including those formed by natural sources and by human activities; 2) amounts, types, and heights of clouds, and 3) distribution of land surface cover, including vegetation canopy structure.