Remote Sensing of CO2, CH4, CO, and H2o from Geostationary Orbit

Abstract:

The Geostationary Carbon Process Investigation (GCPI) combines an imaging Fourier Transform Spectrometer with a geostationary Earth orbit vantage point to realize a transformational advance in monitoring carbon-bearing molecules and water vapor beyond the synoptic capabilities of Low Earth Orbit instruments such as SCIAMACHY, GOSAT and OCO-2. GCPI is designed to measure, several times every day, high-resolution spectra of reflected sunlight with a moderate signal to noise ratio in near-infrared (NIR) bands, that can then be used to obtain simultaneous retrievals of column averaged CO₂, CH₄, CO, and H₂O. The aim of this project is to explore the potential of retrieving vertical profiles of CO₂, CH₄, CO, and H₂O from high-resolution NIR spectra. We perform radiative transfer simulations over clear-sky conditions (as expected to be observed by GCPI) and estimate prospective performance of retrievals based on results from Bayesian error analysis and characterization. Through Observing System Simulation Experiments (OSSEs), we demonstrate the feasibility of retrieving vertical profiles of CO₂ and CH₄ and partial columns of CO and H₂O with high accuracies and precisions. GCPI’s unprecedented observations with high temporal and spatial coverage could be used to drive and constrain Earth system models, improve our understanding of the underlying carbon cycle and water cycle processes, and evaluate model forecasting capabilities.