The North American Carbon Program Plan (NACP)
A Report of the Committee of the
U.S. Carbon Cycle Science Steering Group

Appendix 4a

There are a number of historical, on-orbit, approved, and proposed satellite missions that can contribute to the goals, both near term and long term, of the NACP. Table A4.1 provides a brief compilation of the instruments as they apply to the various processes associated with major land-ocean-atmosphere carbon flux categories, that is, air-sea CO2 and carbon export (to the deep ocean), land-atmosphere CO2, land-atmosphere CH4, and land-sea carbon fluxes. In many cases, if not most, derivation of the specific carbon-related parameters sought from these data sets will need considerable investment in algorithm development and validation. The field experiments conducted under the NACP would offer opportunities for these purposes, but additional independent NASA-sponsored experiments will probably be required to obtain data sets of sufficient diversity and completeness. Note that Table A4.1 is not a comprehensive list of all land, ocean, and atmospheric Earth-observing missions and data sets that might be considered, but are those deemed most critical to the NACP. Also, missions in the time frame of the NACP that are important for aerosol radiation forcing evaluations are listed, because they may be of indirect use in some carbon budget analyses.

The NASA technology development program provides a progression of opportunities from the component level to demonstration missions. Table A4.1 entries include contributions from the Instrument Incubator Program (IIP), the New Millennium program, and the Earth System Sciences Pathfinder (ESSP). The IIP produces prototype instruments that may be deployed on aircraft. New Millennium missions such as EO-1 Hyperion (a passive hyperspectral imager) are satellite demonstrations with limited data acquisition and processing. The ESSP emphasizes a more comprehensive satellite observational and data-processing requirement, but with a limited duration (1 to 2 years); an example is the Vegetation Canopy Lidar (VCL). During the summer of 2001, the IIP and ESSP completed selections. IIP instruments that should be ready for the initial NACP field campaigns include passive and laser CO2 airborne systems. The ESSP selections have not yet been announced. Existing/scheduled instruments in Table A4.1 might contribute to NACP measurement needs, but are far from optimal. The recent ESSP selection process offers the best chance for spaceborne observations to be applied to NACP goals.

Field data collection for process model development, remote-sensing algorithm development, and product validation should be integrated, in parallel with the NACP, and NASA should collaborate with other U.S. and international agencies.

Table A4.1: Remote-Sensing Contribution to Providing Ecosystem Variables Relevant to Carbon Cycle Studies

The NASA Data Assimilation Office (DAO) has proposed the following work in support of the NACP.

A Tailored Meteorological Reanalysis

A 25-year reanalysis of the atmosphere and land surface is required in the plan. This product must be of high spatial resolution (either 50 km or 100 km), with a sufficient number of levels in the planetary boundary layer and troposphere to resolve transport processes of importance to carbon species, and with adequate temporal output of analyzed fields. Similar products are required by other communities (such as climate diagnostics and tropospheric and stratospheric chemists), but it is essential to maintain at least one output stream tailored to the needs of the NACP. Specific requirements of the NACP are (1) sufficient spatial and temporal resolution to resolve the transport of CO2 and other gases, and (2) a suite of diagnostics that enable the effects of sub-grid-scale transport to be accounted for in calculations of the carbon budget. The product must be well validated, documented and quality-controlled; additionally, some measures of uncertainties are needed, particularly for the sub-grid-scale transport parameters.

The following will be specific uses of this reanalysis for the NACP:

1. Help spin-up of a comprehensive land model, including carbon species.

2. Provide boundary conditions for a nested, high-resolution regional assimilation system to produce detailed inventories of carbon species over the United States.

3. Assist forecasting for and analysis of intensive field missions.

This reanalysis can only be produced by a center with operational capabilities. NASA's DAO, one such center, has indicated interest in working with the NACP science team toward providing this product. The reanalysis should be overseen by a steering committee including senior scientists, representatives from major data assimilation centers, and representatives of federal agencies. Maintaining quality and throughput will be a major effort.

The timeline for the project is as follows:

FY 2002

• Formation of the steering committee and the local (DAO) science team. Begin efforts to gather, format, and quality-control the input data. Incorporate the customized (high-frequency) output streams.

• Perform test analyses for target periods, provide these data to potential users, and complete comprehensive evaluations.

• Develop the monitoring system (modify from operational system).

• Prepare computing resources.

FY 2003

• Complete data gathering and preparation.

• Complete test analyses for target periods, provide these data to potential users, and complete comprehensive evaluations.

• Develop the monitoring system (modify from operational system).

• Prepare computing resources.

FY 2004

• Complete tests and development.

• Commence production and maintain throughput; monitor, validate and quality-control.

• Disseminate data to users.

FY 2005/2006-

• Complete to present, maintain production.