Project Funding: 2015 - 2018

NRA: 2014 NASA: OCO-2 Science Team for the OCO-2 Mission   

Funded by NASA

Abstract:
It is well recognized that space-based CO2 data have a large potential for improving carbon surface fluxes due to their global coverage and high data density. The primary challenge for such space-based observations of CO2 columns is that the useful signals for surface flux inversions, namely the spatial and temporal gradients in CO2 columns, are only in the range of a few ppm and thus column CO2 needs to be observed with precisions in the range of 1 - 2 ppm (0.3 - 0.5%) and without significant biases, which puts very stringent requirements on the retrieval algorithm development, its error characterization and validation. It is critical for the success of the OCO-2 missions that even small biases are carefully assessed and characterized with validation, theoretical assessments and retrieval inter comparisons supported by a longer-term program for retrieval algorithm improvements. We propose to use the University of Leicester retrieval algorithm to contribute to the early assessment and improvement of the OCO-2 level 1 and level 2 products in close cooperation with the OCO-2 algorithm and validation teams. One area of focus will be the assessment of the schemes for treating aerosol and cirrus clouds and assessing the quality of the aerosol/cirrus products themselves. Another aspect of our proposal will be the provision of additional validation opportunities over the Amazon region using aircraft profiling and over the Pacific Ocean using observations from the Global Hawk by the GHOST spectrometer; both are regions not well captured by the current TCCON network. Finally, we will make an assessment of the consistency between CO2 retrieval from OCO-2 with those obtained from GOSAT and with ensembles of CO2 model data to gain additional insights into potential biases in the OCO-2 retrievals and to prepare the scientific interpretation of OCO-2 data. This proposal takes advantage of several on-going projects at University of Leicester and it is strongly supported by the UK National Centre for Earth Observations (NCEO). This proposal will directly support the OCO-2 mission and it addresses several tasks outlined in the call such as supporting forward model improvements, assessing retrieval errors and contributing to validation strategies.