Spatio-temporal variability of Suomi-NPP VIIRS-derived aerosol optical thickness over China in 2013

Abstract

The Visible Infrared Imaging Radiometer Suite (VIIRS) aerosol optical thickness (AOT) at 550 nm Intermediate Product (IP) data was evaluated by comparing it with measurements from Aerosol Robotic Network (AERONET) and Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals. The spatial and temporal variations in the regional AOT over China during 2013 (from 24 January to 31 December) were then firstly investigated using VIIRS aerosol IP data. Evaluation of VIIRS IP AOT with MODIS retrievals and AERONET measurements indicated that the performance of the VIIRS aerosol IP product is comparable to that of their counterparts from the heritage MODIS sensor. However, the VIIRS IP can produce more retrievals than MODIS due to its higher spatial resolution, therefore more suitable for regional AOT study. It was found that the VIIRS IP mean AOT over China differs from that of MODIS by −0.032 for the collocated retrievals, with a correlation of 0.928. Compared with AERONET measurements, VIIRS IP AOT shows a negative bias of −0.058 with the standard deviation of the difference of 0.192 over China. Among the 10 typical sites under study, the maximum annual average AOT550 values (with±standard deviation) were found in Chengdu (1.07±0.32), whereas the lowest annual mean AOT550 values were found in FB1 (0.242±0.25). The economically developed regions had high AOT values during all seasons. Based on the distribution of AOT, China can be divided into an economically developed eastern region with high AOT values and less-developed western regions, consistent with the boundary between China’s second and third terrain regions.