Airborne hyperspectral trace gas sensors as testbeds for geostationary air quality missions

Abstract

Next generation air quality sensors are currently planned to launch in the 2020-2021 timeframe. The Tropospheric Emissions: Monitoring of Pollution (TEMPO-United States) and Geostationary Environment Monitoring Sensor (GEMSKorea) are two such missions that will probe the boundary layer and lower troposphere at unprecedented spatial and temporal scales. These missions are designed to provide constraints on chemical forecast models and specifically to answer the question: “What are the temporal and spatial variations of emissions of gases and aerosols important for air quality and climate?” In preparation for these missions a number of airborne air quality field missions have been performed to collect data at similar spatial and temporal scales, and during relevant seasonal air quality episodes. This data is being used to improve the trace gas retrieval algorithms and explore the unique spatial scales and diurnal patterns that will be encountered when the Geostationary experiments are operational. This overview will present details of two of the instruments used during these campaigns, the GEO-CAPE Airborne Simulator (GCAS) and the Geostationary Trace Gas and Aerosol Sensor Optimization (GeoTASO) instruments. The instruments' performance will be compared to predicted on-orbit values for the TEMPO and GEMS sensors in the retrieval of high spatial resolution nitrogen dioxide and formaldehyde. Examples of vertical column retrievals will be presented under various source/weather conditions as well as some of the uncertainties that result from radiative transfer assumptions.