Imagine or draw another straight-line perpendicular to your 0-Doppler wind speed boundary line through the Tulsa radar site. Imagine or draw an arrowhead on the end of the line just imagined or drawn in the red area to indicate the Doppler-detected wind direction at the station. The direction of your arrow, signifying the wind direction in the lower layers of the atmosphere sensed by the radar signal, is generally from the . a. northeast b. northwest c. southwest d. southeast