¹221 Baskin Engineering Bldg
EE Dept., University of California at Santa Cruz
1156 High St.
Santa Cruz, CA 95064
phone: 831-459-4099
email: Vesecky@soe.ucsc.edu

²STAR Lab.
EE Dept., Stanford Univ.
Stanford, CA 94305

³Inst. of Earth Systems Science & Policy
Calif. St.
Univ. Monterey Bay, Seaside CA 93955

⁴Dept. of Oceanography
Naval Postgraduate School
Monterey, CA 93943

HF radars operating at decameter wavelengths (3 to 30 MHz) in ground wave mode are capable of mapping surface currents, waves and winds over relatively large coastal ocean areas (˜ a few thousand sq. km.). Several different HF radar systems are in operation, using different radar system concepts, processing methods and radar frequencies. Users of the data products of HF radars need to know how to merge the data from these different systems into a single set of current maps. Monterey Bay provides a useful test bed for developing algorithms and tools for processing and merging HF radar observations from these different systems, namely Seasonde units from CodarOS Ltd. and multifrequency coastal radars (MCR’s) developed by a consortium based at the University of Michigan. During the year 2000 two MCR’s operating at 4.8, 6.8, 13.4 and 21.8 MHz were sited at Moss Landing and Santa Cruz, California, collecting current maps at hourly intervals. At the same time three Seasonde units were operating from the aforementioned two sites and from Pt. Pinos as well. This suite of radars provided excellent coverage of Monterey Bay. We review observations by both these systems during the summer of 2000. First, we compare the current maps generated by the Seasonde units (operating at 12, 13 and 25 MHz) with observations by MCR units using the frequencies above. We show that both systems produce currents maps with generally the same character, but still with significant differences. We investigate the impact of the different frequencies of operation on the resulting current maps. In particular we compare maps of the same current field and the same time, but made with radars operating on different frequencies. We then discuss methods for adjusting the data from different frequencies to a single basis. We argue that these methods allow radar data from different systems to be merged in a more effective manner than simply using HF radar data from radars operating on different frequencies without regard to operating frequency.

Submitted on January 22, 2003