Abstract：The temporal-spatial characteristics of the tropospheric column NO2 (TroNO2) and total column NO2 (TotNO2) over Sichuan basin since 2004 had been analyzed based on remote sensing data derived from ozone monitoring instrument (OMI) sensor. The regional mean of TroNO2 and TotNO2 over Sichuan basin had an increasing trend, with annual increasing rates 5.12% and 3.42%, respectively. The variations of TroNO2 and TotNO2 were similar pattern, and the correlation between TroNO2 and TotNO2 was closely relative. For the temporal dynamics, the TroNO2 and TotNO2 in spring and summer were larger than those of autumn and winter. The smallest and largest ratio of TroNO2 to TotNO2 appeared in June and December with about 0.51 and 0.66, respectively. The monthly variation of ratio associated closely with the anthropogenic emission. The large values appeared in the urban region of Chongqing and Chengdu, which the economic develop rapidly and air pollution were serious. Especially, the multi-year mean TroNO2 was more distinctive, they were about 10.52′1015 and 8.92′1015 molec/cm2, respectively. The variation trend of TroNO2 and TotNO2 presented strongly correlation With correlation coefficient (R) higher than 0.95 (ratio larger than 0.5) in most region, and the correlation coefficients were approximate to be 1 (ratio larger than 0.8) in the urban region of Chongqing and Chengdu. It proved that the effect of anthropogenic emission was the dominant factor in this regional NO2 concentration upper.
