In this paper we describe the optimal design and its research-to-operation transition of an integrated global observing system of satellites and in situ observations. The integrated observing system is used for climate assessment using sea-surface temperature (SST). Satellite observations provide superior samplings while in situ observations provide the ground-truth. Observing system simulation experiments (OSSEs) were used to objectively design an efficient in situ system to reduce satellite biases to a required accuracy. The system design was peer-reviewed and was then transitioned into operations as a US contribution to the international Global Climate Observing System (GCOS). A system performance measure was also formulated and operationally tracked under the Government Performance Results Act (GPRA). Additional OSSEs assisted the Planning, Programming, Budgeting, and Execution System at the National Oceanic and Atmospheric Administration (NOAA) to maximize design efficiency. This process of research-to-operation and decision making enables NOAA to strategically target its observing system investments. The principles of this specific example may have potential applicability to the other components of GCOS.