Investigation of Long Term Changes in Trace Gases and First Retrieval of Nitrogen Dioxide Surface Mixing Ratio over Major Ports Using Satellite Data
In this present study, we investigated long term changes in trace gases (SO2, NO2, and O-3) from shipping emissions over major ports in each continent using Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) measurements from 2006 to 2015. Additionally, surface nitrogen dioxide volume mixing ratio (NO2 VMR), which can be used to air quality regulation, is retrieved using tropospheric nitrogen dioxide column density and atmospheric measurement data from Atmospheric Infrared Sounder (AIRS) sensor. The long term variation of retrieved NO2 VMRs are investigated. During ten-years, column densities of sulfur dioxide in planetary boundary layer (PBL SO2) and tropospheric nitrogen dioxide (Trop. NO2) decreased by -0.3 DU decade(-1) and -1.8 x 10(15) molecules cm(-2) decade(-1), respectively. However, tropospheric ozone (Trop. 0 3 ) tends to increase (2.9 DU decade(-1)). The decreasing trends of PBL SO2 and Trop. NO2 are thought be due to regulation of NOx and SOx from shipping emission of International Maritime Organization. The NO2 VMRs averaged over Busan, Jebel Ali, Rotterdam, LA, and Melbourne are tends to decrease with 0.64 ppbv decade(-1). Especially, the NO2 VMR in Los Angles, which showed high decreasing trend of Trop. NO2, are decreased 1.5 ppbv per decade. The amount of nitrogen dioxide, one of the ozone precursors, decreased due to the emission reduction policy, while the actual Trop. O-3 tends to increase. Additional research is needed, however, the increase in Trop. O-3 column density is thought to be due to changes in volatile organic compound emissions, one of the precursors of ozone.