Publications

Zhu, L; Xu, QS; Cheng, C; Sun, XW; Wu, PF; Yang, L (2018). Simultaneous determination of aerosol optica depth and exponent of the Junge power law from MODIS shortwave infrared bands over Qinghai Lake. APPLIED OPTICS, 57(22), 6497-6502.

Abstract
The water-leaving radiances for shortwave infrared (SWIR) channels can be negligible, and these channels also contain information on aerosol particle size. Therefore, the satellite-based data of SWIR channels can be used to estimate aerosol particle size over inland waters [Appl. Opt. 39, 887 (2000)]. Supposing the actual atmospheric aerosol size distribution is based on the Junge power law, in this paper an iterative algorithm is used to simultaneously determine the aerosol optical depth (AOD) and the exponent of the lunge power law from Aqua MODIS LIB reflectance data of channels 1.64 mu m and 2.13 mu m over Qinghai Lake. Whether using the constant or variable aerosol complex refractive index (ACRI), the retrieved exponent of the Junge power law is always larger than the product value. Supposing the product values are accurate, for the constant ACRI, there are 68.91% and 25.48% pixels of acceptable retrieval AOD and the exponent of the Junge power-law value, respectively. Likewise, there are 71.63% and 43.75% pixels for variable ACRI. Compared with the retrieval error under constant ACRI, there are 58.65% and 98.72% pixels, with a smaller AOD and Junge power-law index retrieval error under variable ACRIs, respectively. In addition, the precision of the AOD retrieved with variable ACRI is improved when the AOD product is less than 0.17. However, under the current environment with frequent aerosol particle pollution, the same ACRI for the ten wavelengths can achieve results with equivalent accuracy compared with variable ACRI. (C) 2018 Optical Society of America

DOI:
10.1364/AO.57.006497

ISSN:
1559-128X