Variations of urban aerosols in Tokyo metropolitan area based on network camera

Atmospheric environmental issues such as the heat island phenomenon, heavy rainfall and air pollution exist in the Tokyo Metropolitan area. Aerosol in urban area, which is caused by anthropogenic emission, may work to trigger local heavy rain as a cloud condensation nucleus. We evaluated atmospheric turbidity by visual observation based on a cloud-camera network in Tokyo. There are a few studies monitoring whole atmospheric boundary layer (ABL) in urban area continuously for a long period compared to studies of ground observation networks. This study aims to evaluate the variations of urban air quality using network cameras, Lidar, and other ground based observation network (e.g. wind velocity and direction, temperature, SPM). We installed network cameras at two coastal sites around the Tokyo Bay to monitor the air quality above the center of Tokyo. They operated from November 2011 to capture an accumulated urban air turbidity at an interval of one minute. We also used measurements from Lidar and several surface observations in the Tokyo metropolitan area for quantitative observation of aerosol density in the ABL. We confirmed the turbid in urban ABL by camera observation, which was compared with the results from the other observation. Air quality in central Tokyo became more turbid when wind blows from the Tokyo Bay probably due to the emission from industrial districts located in the upwind coastal area.