Comparison of aerosol optical depth over northern China derived from ground-based measurements and MODIS

This study aims to retrieve aerosol optical depth (AOD) from ground-based MultiFilter Rotating Shadowband Radiometer (MFRSR) measurements at Xianghe site in Hebei Province from September 2004 to October 2005. Based on Langley regression, calibrations of MFRSR are carried out and then AODs at Xianghe is derived. In order to evaluate the precision of retrieved AOD, correlations between MFRSR AODs and Aerosol Robotic Network (AERONET) AODs which has been generally approved and used are analyzed. The result suggests that MFRSR AODs and AERONET AODs have a significant linear correlation. The correlation coefficients at 500nm, 670nm and 870nm band are 0.9764, 0.9712 and 0.954, respectively. Meanwhile, comparisons between Moderate resolution imaging spectroradiometer (MODIS) AOD at Xianghe site and MFRSR AODs are carried out. Finally, monthly mean MODIS AODs in the study area are derived from September 2004 to August 2005. Moreover, their spatial distribution and monthly variations are demonstrated.