An improved method for retrieving aerosol optical depth over Ebinur Lake Basin from Gaofen-1

Study on Accuracy Evaluation of MCD19A2 and Spatiotemporal Distribution of AOD in Arid Zones of Central Asia

“…The Muztagh_Ata site (Figure 2a) has some underestimation of high values, which is related to its high altitude; whereas the IAOCA-KRSU and Issyk-Kul sites are overestimated due to the sensitivity of surface albedo to surface salinity, which leads to the errors in the calculation of the surface radiative contribution; Dushanbe, Kashi, Urumqi, and Wusu have some underestimation, which may be because the solar photometer setup sites are more sensitive to the surface salinity. Dushanbe, Kashi, and Urumqi all showed some underestimation phenomena, which may be related to the fact that the solar photometer sites are located near the cities and are polluted by the urban areas; whereas Issyk-Kul and Jinghe I showed some overestimation tendency, which is because the sites are located near the rivers, the surfaces of the dry river beds are heavily salted, and the salts fall on the soil and thus have a certain effect on the albedo values, which is in line with related studies [24,25]. Shihezi and Jinghe II fitted better overall.…”

“…On the time scale, based on the satellite transit period, the sun photometer data within 30 min of the period are selected and averaged. In contrast, for the spatial matching, the satellite retrieval within the 550 km diameter of the CE-318 sun photometer site is used to obtain the effective AOD averages [24,25]. Also in this study, three statistical parameters, sample correlation coefficient (R), root mean square error (RMSE), and mean absolute error (MAE), were used to evaluate the precision of MCD19A2 data.…”