Towards the next generation of tropospheric composition sounding: the NASA TRopospheric Ozone and its Precursors from Earth System Sounding (TROPESS)

The past two decades have been the golden age of tropospheric composition sounding with instruments like the Tropospheric Emission Spectrometer (TES), the Infrared Atmospheric Sounding Interferometer (IASI), SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY),  the Ozone Mapping Interferometer (OMI) harnessing spectral radiation from the thermal infrared to the ultraviolet to pioneer new products such as tropospheric ozone, ammonia, methane, nitrogen dioxide, and water vapor deuterium.  As a new generation of sounders that include both geostationary and low earth orbiting satellites become the anchor of a global air quality monitoring system, there is an urgent need to shift away from an instrument focus, which is a confined to a  band of frequencies,  to a measurement focus, which incorporates the best available information.  The TROPESS project is a new measurement focused approach that uses a common retrieval algorithm applied to a suite of instruments either singularly or in combination.  Building on the heritage of TES, we show how the MUlti-SpEctra, MUlti-SpEcies, Multi-SEnsors (MUSES) algorithm has been applied to produce ozone from TES, AIRS, and OMI as well as its potential to combine CrIS and TROPOMI radiances.  Employing proven optimal estimation techniques, we further show how data produced from MUSES can be ingested into chemical data assimilation providing a comprehensive understanding of global atmospheric chemistry and its evolution.  The suite of products and their scientific impact on atmospheric composition are surveyed.  TROPESS points to a new paradigm that can effectively harness a constellation of data to quantify the rapid changes in the landscape of emissions and their impact on air quality and climate.