Study on spatial-temporal variation of aerosol optical depth over the Yangtze Delta and the impact of land-use/cover

Abstract

Aerosol optical depth (AOD) is a principal indicator used to describe the atmospheric condition and effect of aerosols on radiative transfer in the Earth’s atmosphere. In this study, the spatial-temporal variation of AOD of the Yangtze Delta during 2000–2011 and the impact of land cover were studied. The results show that Moderate Resolution Imaging Spectroradiometer (MODIS) AOD was in good agreement with data obtained from six ground-based Aerosol Robotic Network (AERONET) sun photometers (R > 0.75). The AOD over the Yangtze Delta presented an obvious one year cycle variation from 2000 to 2011. The largest value often appeared in May or June, and the smallest often appeared in December or January. The AOD over main cities has increased gradually over the years. The AOD over urban areas increased faster than that in rural areas. A change of land-use/cover leads to a change of AOD. Areas of land-use/cover with increased intense human activity leads to changes in higher AOD whereas an increase in forested areas leads to an AOD change to a lower value. Forest land has a purification effect against atmospheric aerosols.