Observation of global ocean-atmosphere exchanges from spaceborne sensors

The ocean and the atmosphere are coupled by the fluxes of momentum, heat, and water, but in situ measurements of these fluxes are sparse and uneven. Global fields of these fluxes can be derived from satellite data or obtained from operational numerical weather prediction (NWP) models. The NWP models provide quality control and dynamic interpolation of sparse and uneven data. However, dynamic interpolation is only as good as the model physics and parameterization scheme, and over most of the ocean, there may not be sufficient data for any useful interpolation. Operational NWP models change frequently; the results are inconsistent of climatic studies. Reanalysis to produce long period of consistent data have only been started recently. Adequate observations at temporal and spatial scales significant to global change research can only be achieved from the vantage point of space. Spaceborne sensors provide repeated global observations of some parameters from which these fluxes can be derived. The status and shortfalls of spacebased estimation of the fluxes are summarized and assessed in this report. Satellite data can be assimilated into numerical model to simulate surface fluxes, but the progress in developing assimilation techniques for unconventional satellite data has been slow.