Characterization of the Uncertainties of CO2 retrievals from OCO (Orbiting Carbon Observatory) Observations
Abstract
The Orbiting Carbon Observatory (OCO) mission will make global, space-based measurements of atmospheric carbon dioxide (CO2) with the precision, resolution, and coverage needed to characterize CO2 sources and sinks on regional scales. During its 2-year mission, OCO will fly in a 1:26 PM sun-synchronous orbit with a 16-day ground-track repeat time, just ahead of the EOS Aqua platform. It will carry a single instrument that incorporates three boresighted high-resolution spectrometers designed to measure reflected sunlight in the 0.76-micron O2 A-band and in the CO2 bands at 1.61 and 2.06 microns. OCO is specially designed to be sensitive to near-surface CO2 concentrations and, due to its nadir and sunglint modes, will provide soundings over land and ocean. Here we will discuss the characteristics of OCO soundings and their measurement uncertainties, given by an analysis of the OCO forward model for different surface types, aerosol loadings, and solar zenith angle and we will assess merits of OCO's nadirand glint-viewing modes. We will examine aerosol and cloud statistics derived from MODIS and other satellites to determine the spatio-temporal distribution of the OCO measurement errors and to obtained the expected number of cloud-free OCO soundings from which multi-shot measurement errors are calculated. Finally, we will discuss how well we expect OCO's column-CO2 measurements can constrain the surface sources and sinks. These investigations will provide important feedback to help isolate areas where the retrieval must be improved and give guidance on the optimal observation and sounding selection strategy for OCO.
- Publication:
-
37th COSPAR Scientific Assembly
- Pub Date:
- 2008
- Bibcode:
- 2008cosp...37..334B