INSTKUCTIONS FOR MAKING PILOT BALLOON OBSERVATIONS 43 



cised in selecting data to be entered on tliis form. Questionable data 

 should not be recorded. To augment the data regularly obtained by 

 means of pilot-balloon observations, when a scheduled pilot-balloon 

 observation is missed because of low clouds and the height of the clouds 

 at that time (i. e., within 1 hour before or after) is obtained by ceiling 

 balloon or ceiling light, the data so obtained are to be entered on 

 Form No. 1113-Aer. and included in the summary on the reverse side 

 of the form. For such entries the words "ceiling light',' or "ceiling 

 balloon," as the case may be, are to be entered under "Remarks". 

 The velocity of the cloud will, of course, be omitted from such entries. 

 Cloud-height data obtained from "delayed" pilot-balloon observa- 

 tions (more than 1 hour before or after the scheduled time) are also 

 to be entered on this form and included in the summary by combining 

 them with those of the nearest scheduled time. When all entries for 

 the month have been made, the cloud data are to be tabulated accord- 

 ing to cloud types and grouped into the four scheduled observation 

 times. In tabulating the entries according to types altocumulus 

 castellatus (Ace) will be classed as altocumulus (Ac), fractostratus 

 (Fs) as stratus (St), fractocumulus (Fc) as cumulus (Cu) and cumu- 

 lonimbus mammatus (Cm) as cumulonimbus (Cb). The average 

 hights and number of entries are then to be obtained for each category 

 and the results entered in the summary on the upper half of the 

 reverse side of the form. Copies of these tabulations and computa- 

 tions are to be retained in the station file each month and yearly 

 values, obtained therefrom are to be rendered on a separate blank 

 form with the December records each year. On the lower half of 

 this same form the yearly maximum altitude and maximum velocity 

 data are to be entered as indicated below. 



135. All cloud entries on Form No. 1113-Aer. resulting from pilot- 

 balloon observations are to be converted into the punch-card code 

 and then copied onto the appropriate Form No. 1114A-Aer. The 

 following values are to be used in converting the cloud data into the 

 punch card code: 



136. The cloud velocities as entered on Form No. 1113-Aer. are to 

 be converted to whole numbers and entered on Form No. 1114A-Aer. 

 as two-digit figures i. e., 01, 02 — 09, 10 — 58, etc. 



