Tropospheric Ozone Derived from Suomi NPP OMPS Satellite Measurements

The Suomi National Polar-orbiting Partnership (NPP) satellite was launched on October 28, 2011 and placed into a sun-synchronous polar orbit with equator crossing local time of about 13:30. The Nadir Mapper (NM) instrument onboard the NPP satellite is part of the Ozone Mapping and Profiler Suite (OMPS) and measures total column ozone over the entire Earth outside of polar night. Global tropospheric column ozone (TCO) for March 2012-present is derived by subtracting coincident stratospheric column ozone (SCO) from OMPS-NM total column ozone measurements. SCO is calculated from both MLS ozone profiles and MERRA-2 Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) assimilated ozone profiles. We have investigated different methods of constraining SCO, including MLS interpolated ozone, and estimated uncertainties associated with each method. The derived TCO is tested against ozonesondes and the Goddard Earth Observing System (GEOS) model with the Global Modeling Initiative (GMI) chemical mechanism (replayed to observed meteorology) for identifying possible systematic errors and the ability to capture large-to-small scale geophysical features in tropospheric ozone from daily to inter-annual timescales. For these comparisons we account for a limited OMPS sensitivity to the boundary ozone layer by applying efficiency factor to GMI and ozonesonde data. The GMI simulation is used to further evaluate the loss of sensitivity to ozone below 700 hPa for OMPS retrieval and to better understand the differences with models.