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HF radar surface currents — Southern California

Find high-frequency radar surface current measurements along a coast — the upper 0.3–2.5 m of the water column, every hour, for thousands of grid cells.

What this teaches

  • Querying the IOOS HF Radar network (IOOS_HFRADAR)
  • Reading radial-sweep variable lists (VELU, VELV, ESPC, etc.)
  • Combining HF radar with satellite SST or wind to interpret surface flow

Source used: IOOS_HFRADAR (IOOS HF Radar ERDDAP)

Prompt

Show me HF radar surface current stations off Southern California with
recent data. List their variables and link me to ERDDAP for one of them.

Transcript

1. Scope to the SoCal Bight

search_datasets(
  collections = "IOOS_HFRADAR",
  bbox = "-127,32,-117,42",
  limit = 5
)

64 matching items along the West Coast. Top results in the SoCal area:

ID Title Bbox
USC_SCTB Radials for SCTB -119.13, 33.22 → -117.66, 34.42
USC_SCPF Radials for SCPF -118.78, 33.30 → -117.81, 34.11
USC_SCNB Radials for SCNB -118.41, 33.20 → -117.50, 33.81

All three are USC (University of Southern California) stations on the IOOS HF Radar ERDDAP at https://hfradar.ioos.us/erddap.

Variables per radial sweep include: time, flag, station, antenna_lat, antenna_lon, VELU, VELV (the u/v current components), VFLG (velocity flag), ESPC, ETMP, EDTP, EASN (error metrics), MAXV, MINV, RNGE, BEAR, VELO, HEAD, SPRC.

2. Get the ERDDAP form URL

get_item(collection = "IOOS_HFRADAR", item_id = "USC_SCTB")

The asset list typically includes asc, csv, csv0, csvp, das, dataTable, dds, dods, htmlTable, nc, and the dataset's ERDDAP HTML form.

Result the agent gave

"64 IOOS HF radar items match the U.S. West Coast bbox. The ones currently active in the SoCal Bight are all USC-operated:

  • USC_SCTB — bbox -119.13°W to -117.66°W, 33.22°N to 34.42°N (Santa Catalina / Channel Islands toward Long Beach), most-recent obs 2025-06-05
  • USC_SCPF — bbox -118.78°W to -117.81°W, 33.30°N to 34.11°N (Palos Verdes / San Pedro Bay), most-recent obs 2025-06-19
  • USC_SCNB — bbox -118.41°W to -117.50°W, 33.20°N to 33.81°N (Newport Beach inner Bight), most-recent obs 2025-06-05

Each is a RadialSweep dataset with u/v velocity components (VELU, VELV) and a full set of quality / error flags (VFLG, ESPC, ETMP, EDTP, EASN, MAXV, MINV, ERSC, ERTC). The spatial framing is radial-from-antenna rather than gridded — for a gridded total-currents product, search the same collection with q='totals'.

Download via the IOOS HF Radar ERDDAP at https://hfradar.ioos.us/erddap — for example https://hfradar.ioos.us/erddap/tabledap/USC_SCTB.html exposes the form for CSV / NetCDF / OPeNDAP output."

Variations

  • Different region: Mid-Atlantic Bight bbox -77,35,-69,42 returns Rutgers / U-Mass / U-Delaware stations.
  • Aggregated current grid product: search q = "totals" within IOOS_HFRADAR for the gridded total-current (not radial) products.
  • Combine with wind: add NDBC to the collections list to compare HF radar surface flow with measured wind at nearby buoys.