Weather Radar Fundamentals


Doppler Velocity Measurements » Large-Scale Wind Interpretation » Directionally Sheared Winds

A plan view of idealized radial velocity.  Colors to the left of the radar are blue and green, while colors to the right are red and yellow.  A line of gray, indicating velocities of zero, forms an  "S" shape and intersects the location of the radar in its center. Red and yellow colors lie to the right of the "S" and blue and green colors lie to the left of the "S".

Of course, winds are rarely unidirectional, so let's look at a more complex case. At the location of the radar (and therefore near the surface), the maximum inbound velocity is just to the south, and the maximum outbound velocity is to the north. Connecting the inbound velocities to the outbound, we see that the wind is probably blowing from the south and perhaps slightly from the west. The speed is about 20 to 25 m s-1, as shown by the maximum and minimum values just next to the radar location.

Let's next determine the winds at the level of the first range ring.