Estimated Actual Velocity (EAV)

What is EAV?

EAV is a new AWIPS radar tool that will be

included in the AWIPS 8.2 software to be deployed in January

2008.

What does EAV do?

EAV will provide the radar meteorologist with an

estimated actual wind from the Base Velocity WSR-88D

data.

How does EAV work?

EAV uses the solution of a right triangle to provide an

estimate of actual wind speed.

EAV = Doppler wind / COS @where @ is angle of wind

direction off Doppler radial

Determination of Doppler Estimated Winds Based on Degrees off Radar Beam

Black arrow – Doppler windBlue arrow - 2nd component of windRed arrow – Actual wind

EAV = Doppler wind / COS @

EAV@

Base velocity was 50 kts at point where EAV = 90 kts

Base velocity was 38 kts at point where EAV = 60 kts

Uses of EAV?1. Estimate actual wind speeds in a squall line.2. Estimate winds in a hurricane.3. Estimate winds in a blizzard.

Cautions – The estimated wind direction by the radar meteorologist must be accurate or bad EAV data will result. If the input wind direction is greater than ~70 degrees off radial, no EAV will be calculated.