High Accuracy Near-Real-Time Sea Surface Height Observations from the Jason-2, Jason-3, and SARAL Missions

In this paper, we describe our approach and results from the generation of high-accuracy near-real-time sea surface height products for the Jason-2, Jason-3, and SARAL satellite altimeter missions. Orbit altitude accuracy is perhaps the most significant discriminating factor between near-real-time (e.g., few hours) and longer-latency (e.g., 2-3 days or longer) sea surface height products from these missions. As such, our approach is primarily aimed towards generating high-accuracy orbit altitude estimates for the host satellites in near-real-time. For Jason-2 and Jason-3 we generate 3-5 hour latency GPS-based orbit solutions with radial accuracies of < 1 cm (RMS). For SARAL we use inter-satellite SARAL/Jason-2 sea surface height crossover measurements to generate 5-7 hour latency orbit altitude estimates with accuracies of < 2 cm (RMS). The use of inter-satellite crossover measurements has the added benefit of leveling the SARAL sea surface height measurements to those from Jason-2. We then use the orbit altitude estimates to generate high-accuracy near-real-time sea surface height products for these three missions that have similar accuracies to those available on longer-latency products. The combination of the resulting sea surface height measurements from these three missions facilitates high-accuracy mapping of the ocean surface topography in near-real-time (< 7 hours), with the benefits of the spatial sampling available from three coincident missions.