High-frequency (HF) radar is an important tool for real-time coastal ocean monitoring, yet the long-term success of radar networks depends on more than instrument deployment alone. In many regions, HF radar remains confined to short-term scientific projects and does not fully transition into sustained operational service. Taiwan’s experience suggests that the key challenge is not only technical performance, but how a radar network acquires operational legitimacy: how it becomes reliable, useful, and publicly supportable as part of coastal observing infrastructure. This presentation examines Taiwan’s development of a high-resolution HF radar network as a case of transforming a research-oriented technology into an operational marine observing system.

Taiwan is a particularly relevant setting for this discussion. As an island with a dynamic coastal ocean, narrow shelf environment, strong monsoonal forcing, frequent typhoons, and high exposure to marine hazards, Taiwan requires sustained and high-resolution observations of nearshore and shelf-sea conditions. Our radar systems operate at 27–30 MHz with relatively wide bandwidth and phased-array antennas optimized for coastal monitoring. The typical observing range is about 40 km, with raw range resolution of approximately 600 m and gridded products at 2 km resolution. Rather than maximizing offshore coverage alone, this design emphasizes high-resolution monitoring of the coastal ocean, where short-scale circulation, wave conditions, and many societally relevant processes occur.

To date, 25 stations of this open-architecture radar system have been deployed in Taiwan. These stations are operated, maintained, and quality-controlled by our own team, and their products are being progressively integrated with pre-existing long-range CODAR SeaSonde observations to form a more complete island-wide coastal observing network. This integration of short-range, high-resolution radar data with longer-range commercial radar coverage provides a practical pathway toward a multi-scale operational monitoring system around Taiwan.

A central lesson from Taiwan is that operationalization is the basis of government support. Public funding does not become stable simply because a system is scientifically interesting or technologically advanced. It must be justified through continuity of service, reliability of data, quality-controlled products, and visible relevance to hazards, governance, and marine applications. In this sense, operational mode is not only a technical condition but also an institutional one: it is the pathway through which the observing system gains legitimacy.

Another key lesson is that technological localization is essential. A system that can only be used, but not diagnosed, modified, repaired, or extended, is deployable but not truly operational. Long-term sustainability requires local capacity in system integration, signal processing, maintenance, quality control, and software development. Our experience shows that open architecture is therefore critical, not as an ideological preference, but as an operational necessity. The radar platform adopted in Taiwan was originally developed at the University of Hawai‘i, and its non-black-box design has been fundamental to this process. Through collaboration with the original developers, including co-author Pierre Flament, technology transfer extended beyond instrument deployment to the building of local expertise in operation, quality control, debugging, and system improvement. Although open systems may initially require iterative refinement than black-box platforms, their transparency makes problems actionable and supports long-term learning.

One of our team’s major contributions has been the establishment of a real-time monitoring dashboard covering all 25 radar stations and nearly 400 antennas. This information-engineering system tracks system health and data status in real time, using operational indicators, alert logic, and foundational quality-control metrics. It has become a key accelerator for debugging, system diagnosis, and algorithm improvement by creating direct feedback loops between instrument behavior, data products, and processing performance.

Based on this open framework, Taiwan has also successfully developed bistatic HF radar capability. We will present new results from this configuration, including system synchronization, signal-processing adaptation, and bistatic radial velocity retrieval. For high-resolution coastal systems, bistatic development is important not only as a technical achievement, but because it expands geometric flexibility and strengthens the observing potential of the network.

Taiwan’s experience suggests that the future of operational HF radar, especially in resource-constrained coastal states, lies in the co-development of technological localization, real-time system intelligence, quality-controlled products, and public legitimacy. In this sense, Taiwan’s radar network is not only a regional technical case, but also a broader example of how marine observing infrastructure can be made operational, resilient, and useful for interdisciplinary ocean science.

hf radar,coastal monitoring,operational