PRESENT STATE OF OUR KNOWLEDGE OF THE UPPER ATMOSPHERE. 109 
vertically isothermal, but the temperature of the vertical columns will not 
e the same for all. Over the depression the temperature will be raised. 
He finds that the value of H, is diminished by 3°5 times the difference of 
height of the ‘ homogeneous’ stratosphere at the normal and increased 
temperatures. If the increase of temperature is 20° C., the decrease in 
AH, is about 2 km. 
IV. (d) Annual Variation of Temperature. 
A question of some interest is the magnitude of the yearly variation of 
temperature at different heights. Berson! concluded from the results of 
the manned balloon ascents that the absolute range showed practically 
no diminution up to 5 km., and that above that height, although there was 
a tendency to decrease, the ascents were not numerous enough to warrant 
definite conclusions. He gives the following values for the range, taken 
as the difference between the extreme temperatures observed :— 
Height | Surface Mee acs <8 4 5 6 7 | 8km. 
j Range 
[e} [e) ° ie) ° oO ° i} ° | 
(31-6) | 29-7 30-4) 31:8] 3282] 31-0] 273] 350 litsc.| 
| No. of Cases . 4 | 
— 56 50 40 32 20 11 5 
___ Teisserenc de Bort” deduced from his observations with ballons-sondes 
‘in 1898-1900 that the range decreased considerably with the height. 
Taking as the range the difference between the extreme values of the 
monthly mean temperatures he found the following results :— 
Height Surface 5 kn. 10 km. 
5 16°9 14°°6 LLSFOEC. 
The following table gives the range in degrees C., taken from the 
monthly mean temperatures, for ten stations, up to a height of 15 km. 
Column M gives the number of months in the year in which observations 
were obtained. The values for the ten stations together are the ranges 
of the mean temperatures and not the mean of the ranges for different 
stations :— 
Range 
Annual Range from Monthly Means. 
Height 
| Berlin Meer Paris | England Pavlovsk| Uccle | Zurich 
Balloons 
26 | 12 21 16) 12/19 | 10 26 | 12] 21) 12] 19 | 11 
15 | 12 16 17 | 12} 22);10 25)12/18)12}] 20 | 11 
13 | 12 14 17 | 12} 21) 10 | 22) 12] 19/12!] 16 | 11 
17 | 12 15 LSI Ze) 21 OR SSE tee Oona v4 77 
16 | 12 17 17 | 12 | 20 | 10 25 | 12 | 22) 12) 16 | 11 
17;12} — |19|12| 19) 10 | 21/12] 95}12) 21 | 11 
20}12; — | 21/12/18] 10; 21|12|26|12| 23 | 41 
18/12} — | 22/12] 22| 10) 16/12|99/12| 95 | 11 
18/12| — | 23/12] 21|10|16/121 26/12! 26 | 11 
15/12} — |19| 12] 18| 10/14/12] 294/12) 21 | 10 
11|12; — |16|12] 16/10! 16|12/17/12! 12 | 8 
14/12} — /|18/12/14|10| 22|/12/12/12/| 14 | 8 
19/12, — | 20/12/15 | 10; 21|12/13]12| 15 | 6 
21) 8/° — |19/12|/25| 9/17| 9/18/12) 93 1 5 
25) 7) — |18/12/28| 9,10] 6/15/11 (6) |] 2 
28; 6} — |22/11/95| 7/11] 5/15/11. @)| 2 
| | 
- Wissenschaftliche Luftfahrten, III. 2 G. R., 1900, and Met. Zit., 1901. 
