; 
: 
PRESENT STATE OF OUR KNOWLEDGE OF THE UPPER ATMOSPHERE. 121 
and a more regular increase than winds from other directions. This is 
probably due, in part at least, to the fact that the general drift of the 
upper air is from W. to E. The rotations for Berlin are in nearly all cases 
greater than in England, but S. winds in summer form an exception. 
The difference in the upper layers is greatest in the case of N. winds which 
back slightly in the upper air in England, both in winter and in summer. 
The rotation is larger in winter than in summer, indicating that in the 
latter season convection is more vigorous in equalising the wind in the 
lower layers. The departures of the wind at higher levels from the direction 
at 500 m. show that this must be the case since these departures tend to be 
slightly larger in summer than in winter. S. winds again form an exception 
and have total rotations slightly larger in summer than in winter in 
England. 
The same observations were used to obtain the increase of the velocity 
with height. 
The following table gives in metres per second the mean observed 
surface wind and the mean excess of the observed wind at each height 
above the surface wind at the time of observation. The number of obser- 
vations in England is slightly less than before because in some cases the 
direction only was observed at ground level.! 
Increase in Wind Velocity. 
B=Berlin, E=England. N=number of observations for England. 
Heights Aut | 05 km, 1-0km,|1°5 km,|2:0km.| 2°5 km,| 8:0 km. 
Winter. 
B. : 75 78 | 80 | 80 | 87 | 96 | 10-5 
W.; E. 59 | 72 | 96 | 105 | 108 | — — 
N. 59 59 59 32 7 a= — 
B. : 58] 38 | 41 52 | BT | 68 | 7-2 
N. < E. 55 | 53 | 68 | 75 | 7:2 | 11:8 | 144 
N. .| 30 30 30 16 6 2 2 
B. 56 54 57 54 | 58 53 | 55 
E. ; E. 6:3 6:3 72 66 | 69 4:2 | 2:8 
N. 37 37 37 18 10 i 5 
B. 59 75 72 | 77 | UT | 94 | 10:0 
Sh eee 49 | 64 | 7:8 8:2 71 58 | 7:0 
N. ; 50 50 50 29 15 9 7 
Summer. 
B ; 62 | 4:5 61 63 | 66 | 76 8:2 
W.iE 59 53 | 69 | 83 85 | O1 87 
N 107 | 107 | 107 67 38 26 11 
f B 4:9 29 | 3:9 43 | 38 | 3:9 5:9 
N. E 58 | 4:1 53 | Bl 45 | 48 8:4 
iN 39 | 39 | 39 | 21 | 14 7 4 
(B 521 25 | 34 | 361 39 | 44 | 93 
E. | E 5-4 3°5 4°4 4°3 51 56 6-2 
N 33 33 33 25 18 14 11 
B 56 3:3 35 55 42 | 56 5:0 
8. 1E : 41 50 | 83 | 98 79 78 73 
N 61 61 61 37 | 16 8 Zl 
1 The absolute values of the velocities are not inter-comparable because ascents 
are not made in strong winds in England and the anemometers are of different types 
. and have not been compared. 
