High Frequency Radar Surface Currents Help

Surface Current Map

The surface current map displays colored vectors showing the observed or predicted surface current for the selected time period - where the direction of the arrow indicates the current direction and the color indicates the speed (color scale at bottom).

Clicking on one of the arrows will bring up the time series plot for that location (detailed below).

Search by Latitude and Longitude

By entering a latitude and longitude, the current vector closest to that location will be highlighted, and the time series plot will be displayed. The latitude and longitude entered must be within 10 miles from the nearest vector.

Map time selection box

The map time selection box shows the time and type of data (observed or predicted currents) presently being displayed on the map. The Previous, Next and Start Animation buttons can be used to cycle through available data. Additionally, a drop-down menu can be used to see and select all possible time periods.

Data is available 48 hours before and 48 hours after the present time. Observations are typically available 1 to 2 hours prior to the present hour of data. The time stamp represents the center of the hour for when the data was observed (e.g. a time stamp of 15:00 indicates the data was collected from 14:30 to 15:30). Predicted data will be presented until the most recent observations are available.

Time series plot

When clicking on a vector or entering a latitude and longitude, the time series plot window is displayed for that grid point. The top plot shows the observed and predicted surface current speed for the selected grid point, and the bottom plot shows the observed and predicted surface current direction for the selected grid point. The current direction represents the direction the current is flowing towards.

The vertical dashed line shows the present time and the green triangle at the bottom of the plot shows the time presently being displayed on the map.

The plot can be printed or saved using the icons on the upper right.

The text data values for the plotted time series can be displayed by clicking the data tab on the upper right.