Initial Inflight Calibration Status of the OCO-2 Mission

Abstract:

The Orbiting Carbon Observatory-2 launched on July 2^nd, 2014, and is scheduled to begin initial observations in early August. In addition to the standard operational science measurements, the early phase of the mission will see intensive special calibration measurements. These will seek to validate the ground radiometric, spectral and spatial calibration of the three-band spectrometer.

Radiometric calibration validation will be primarily accomplished via vicarious calibration using the playa at Railroad Valley, NV, from techniques demonstrated by the joint OCO-2/GOSAT fieldwork. Additional constraints will be established via lunar calibration using the USGS ROLO database. Critical to the radiometric calibration will be dark subtraction that will be validated via regular dark measurements.

Spectral calibration validation will rely heavily on the OCO-2 Level 2 algorithm. By inspecting the residual fits, it will be possible to constrain the uncertainties in wavelength error and infer possible errors in the instrument line shape model. Additional constraints on line shape stability will be provided by monitoring the Doppler shift of solar lines during an extended solar calibration.

Spatial calibration validation will be based on lunar calibration, with additional information provided by observing coastline crossings.

This presentation will summarize the current state of calibration knowledge leading up to the first public data release of the OCO-2 L1b data product.