enhanced dust index for Asian dust detection with MODIS images

• Published in: International journal of remote sensing Vol. 34; no. 19; pp. 6484 - 6495
• Main Authors: Han, Lijian, Tsunekawa, Atsushi, Tsubo, Mitsuru, Zhou, Weiqi
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 2013
• Subjects: absorbance; aerosols; Animal, plant and microbial ecology; Applied geophysics; Bands; Biological and medical sciences; Dust; Earth sciences; Earth, ocean, space; EDI; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; Image detection; Internal geophysics; moderate resolution imaging spectroradiometer; MODIS; Reflectance; Reflectivity; satellites; Teledetection and vegetation maps; temperature; time series analysis; Visibility; Far East; Asia; time series analysis; atmosphere; detection; Space remote sensing; near infrared radiation; Index; Density distribution; Standards; Optical density; Temperature difference; Meteorological station; brightness temperature; channels; standard samples; imagery; spatial resolution; performances; dust; Reflectance
• ISSN: 1366-5901; 0143-1161; 1366-5901
• DOI: 10.1080/01431161.2013.802055

An enhanced dust index (EDI) for Moderate Resolution Imaging Spectroradiometer (MODIS) solar reflectance bands is proposed that provides a means to detect the dust status of the atmosphere. The EDI utilizes only solar reflectance channels and may therefore be applied consistently to the entire MODIS time series records (1999 to present) for daytime dust observation, producing a higher spatial resolution (500 m) dust result than that from thermal-infrared records (1000 m), which were developed previously and are currently being used. The index introduces dust optical density (α), which can be simply estimated by spectral unmixing, into the normalized difference between reflectance at near-infrared (2.13 μm) and blue (0.469 μm). Dust severity can thus be rated from weak to severe within a standard range of –1 to 1. The index was applied to 11 typical dust events during 2000–2010 in East Asia, where it showed good coherence with meteorological station-observed visibility (R² = 0.7909, p < 0.05) and standardized visibility (R² = 0.7128, p < 0.05). Further comparison with the commonly used normalized difference dust index (NDDI) and brightness temperature difference (BTD) between MODIS bands 31 and 32 also indicated a better performance of the EDI in identifying the spatial and density distributions of dust. Previously applied satellite-based dust indices, particularly for the visible and near-infrared, can therefore be improved for a better quantification of dust aerosols.