The continuous monitoring of desert dust using an infrared-based dust detection and retrieval method

Airborne dust and sand are significant aerosol sources that can impact the atmospheric and surface radiation budgets. Because airborne dust affects visibility and air quality, it is desirable to monitor the location and concentrations of this aerosol for transportation and public health. Although aerosol retrievals have been derived for many years using visible and near-infrared reflectance measurements from satellites, the detection and quantification of dust from these channels is problematic over bright surfaces, or when dust concentrations are large. In addition, aerosol retrievals from polar orbiting satellites lack the ability to monitor the progression and sources of dust storms. As a complement to current aerosol dust retrieval algorithms, multispectral thermal infrared (8 - 12 micron) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Meteosat-8 Spinning Enhanced Visible and Infrared Imager (SEVIRI) are used in the development of a protype dust detection method and dust property retrieval that can monitor the progress of Saharan dust fields continuously, both night and day. The dust detection method is incorporated into the processing of CERES (Clouds and the Earth's Radiant Energy System) aerosol retrievals to produce dust property retrievals and estimates of direct radiative forcing by the dust. The Aqua MODIS serves as the primary imager data source during the development of the method, while SEVIRI data are used to assess and improve off-nadir performance of the dust detection/retrieval methods. The chronologies of aerosol properties and measurements of direct radiative forcing by dust storms will be presented at the conference.