Table 48. 



MEAN DIRECTION OF THE WIND BY LAMBERT'S FORMULA. 



E - JV+ (iVE + SE - NIV- SIV ) cos 45° 



tana 



N- S+ [NE + NIV- SE - SIV) cos 45° 

 Multiples of cos 45\ 



Form for Computing the Numerator and Denominator. 



a is the angle between the mean wind direction and the meridian. 



The signs of the numerator («) and denominator («') determine the quadrant inwhichalies. 



When )i and d are positive, u lies between N and E : 



^ = NE. 



When tt is positive and d negative, a lies between S and E: — =SE. 



When 71 and d are negative, a lies between S and W : — = SIV. 



When n is negative and d positive, a lies between N and W: — = NIV. ■ 



148 



