1. AWIPS-2 HF Radar Sea-Surface Current Product By Ross Van Til Contributions by: Nicole Kurkowski, OS&T Dr. Pablo Santos, WFO Miami Dr. Jack Harlan, NOAA IOOS Dr. Brian Haus, U of Miami

2. Learning Objectives Understand basics of how HF coastal radars retrieve sea-surface current data Grasp the areal coverage HFRs provide Characterize the spatial and temporal resolution of sea-surface current data provided in AWIPS-2 Classify the types of currents represented in the data Summarize operational applications

3. Performance Objectives Access sea-surface current data in AWIPS-2 Manipulate the AWIPS display to optimally view/interpret the data Use data appropriately to enhance marine products and services

4. What is HF Radar Operates in high-frequency radio portion of EM spectrum Wavelengths in the 10-100m range

5. Types of HF Radar  Compact antenna/Direction Finding (CODAR) 95% of US HFRs Range of up to 200 km Broad beam Antennae occupy small amount of space

6. Types of HF Radar  Phased-array/Beam forming (OSCR,WERA) Range of 80-120 km Narrow beam Better temporal, spatial resolution Capable of resolving complex current fields Can better measure waves

7. How HF Radar Works

8. What HF Radars Provide Sea-Surface Currents (speed and direction)  Range = 1 to 200 km  Spatial resolution = 0.2 to 6 km  Temporal resolution = 10 to 60 min  Velocity accuracy = 5 to 10 cm/s  Directional accuracy = 10 degrees  Depth of measurement = 1-2 m Surface wind direction and speed can also be measured Some types (OSCR, WERA) can also measure wave height, period, and wave directional spectra

9. Surface Currents and Wave Forecasting Following Current

10. Surface Currents and Wave Forecasting Opposing Current

11. HF Radar Network 11 IOOS Regional Associations serve the entire US Coastline, including the Great Lakes, Caribbean, and Pacific Territories

12. CONUS HF Radar Coverage

13. OCONUS HF Radar Coverage

14. Sea-Surface Current Data in AWIPS-2

15. Accessing the Data in AWIPS-2

22. Preferred Data Combination?

23. Sampling Current Speed

24. AWIPS-2 Data Loop

25. AWIPS-2 Data Characteristics Temporal Resolution = hourly One hour average centered on hour Spatial Resolution varies from 1km to 6km Data is spatially averaged Data that does not pass a QC check will not be displayed (may see holes in data) Areal Coverage = good portion of contiguous US and some OCONUS

26. Daytime vs. Nightime % good data

27. Other Considerations Range/coverage reduced in areas of strong winds and high waves Interference from distant sources can occur Need “deep” water

28. Oceanic Currents

29. Tidal Currents

30. Wind-Driven Currents

31. Operational Applications Wave Forecasting Surface currents can significantly alter wave properties (steepness/height)  Opposing current increases steepness/height  Following current decreases steepness/height Surface currents can effect on wave growth rate Compare to RTOFS current data which is input to Nearshore Wave Prediction System (NWPS)

32. Other Operational Applications Rip current prediction Trajectory analysis for oil spill and search and rescue situations Water quality monitoring Harmful Algal Bloom Forecasts Fisheries and Ecosystem Management

33. Summary Mature technology for measuring ocean current velocities over large coastal areas Numerous important applications Hourly, near-real-time Spatial resolution in AWIPS-2 = 1-6 km Up to 200 km range Performs better during daytime

34. References and Data Sources on Web IOOS HF Radar Page: http://www.ioos.noaa.gov/hfradar/welcome.html http://www.ioos.noaa.gov/hfradar/welcome.html NDBC Real-Time Data: http://hfradar.ndbc.noaa.gov/ http://hfradar.ndbc.noaa.gov/ CORDC Site (real-time data and much more) http://cordc.ucsd.edu/projects/mapping/maps/ http://cordc.ucsd.edu/projects/mapping/maps/