Fires and smoke in Russia captured by Aqua on June 29, 2012. Aqua true color image and fire detections in upper panel, dark target AOD 10 Km product in lower panel.
Forest fires in Oregon and California on August 5th 2013. MODIS Aqua true color image on the left and MODIS 10 km dark target AOD retrieval on the right. The image on the left was originally publish on the NASA Earth Observatory website. The dark target AOD overlay was produced using the NASA Worldview website.
Haze and pollution in India on January 10th, 2013. Aqua true color image in the center, AOD 10 km product (left) and 3 km product (right). Note the much finer detail of the 3 km product especially in and around the areas of heavy smoke and cloud. The AOD product images were produced using the Panoply tool.
The effect of aerosols is one of the greatest sources of uncertainty in climate modeling. Aerosols vary in time in space and can lead to variations in cloud microphysics, which impact cloud radiative properties and climate. The Dark-Target (DT) aerosol retrieval algorithm is applied to multispectral satellite data, and derives aerosol properties including aerosol optical depth (AOD) over land and ocean, and spectral AOD and aerosol size parameters over ocean. Products of the DT retrieval are used to develop global and regional aerosol climatology, to study the interaction of aerosols with clouds, and for air quality assessments and forecasts.
There are two separate and distinct “Dark Target” (DT) algorithms. The first one is used for retrieving aerosol information over ocean (dark in visible and longer wavelengths) and the second one over vegetated/dark-soiled land (dark in the visible). In theory, these algorithms can be applied to any sensor that measures reflectance in appropriate wavelength bands covering visible (VIS), near-IR (NIR) and shortwave-IR (SWIR). Originally developed for use with MODIS data, the DT retrieval algorithm is being ported to new and future sensors including VIIRS.
This website is intended to be the primary source of on-line information for the dark-target satellite aerosol retrieval algorithm. Information on the site is intended for both beginners and advanced users.