Zhang, P, Lu, NM, Hu, XQ, Dong, CH (2006). Identification and physical retrieval of dust storm using three MODIS thermal IR channels. GLOBAL AND PLANETARY CHANGE, 52(4-Jan), 197-206.
In this paper, the dust event on 7 April 2001 in northern China is investigated with three MODIS thermal infrared (IR) bands. It is found that for the dust cloud, the observed 11 mu m minus 12 mu m brightness temperature difference (BTD) is always negative, while the BTD of 8.5 mu m minus 11 mu m varies from positive to negative depending on the dust concentration. Based on these distinguishing properties, we develop a dust mask algorithm to identify the dust storm occurrence and spatial extent. The algorithm can be used successfully in both the daytime and nighttime. Using the Mie spherical scattering theory, the thermal radiation transfer through the single dust layer is performed with the widely used forward model DISTORT. Our calculations show that the dust-like aerosols can well explain the observed BTD although both of the complex refractive index and particle size of aerosols will significantly influence the BTD. When the complex refractive index is fixed (dust-like aerosols in this paper), then the dust optical thickness and effective radii of dust particles can be retrieved from the brightness temperature (BT) of the 11 mu m channel and the BTD of 11 mu m minus 12 mu m channels, respectively. The integral dust column density can also be derived from the retrieved dust optical thickness and effective radius. (C) 2006 Elsevier B.V. All rights reserved.