44 INSTRUCTIONS FOR MAKING PILOT BALLOON OBSERVATIONS 



137. Maximum altitude and maximum velocity data. — On the lower 

 half of the reverse side of Form No. 1113-Aer. the following summar}^ 

 data are to be entered: 



1. Absolute maximum altitude above sea level reached during the month. 



a. Corresponding wind direction and velocity. 



b. Date and time. 



2. Maximum wind velocities for the month as follows: 



Surface-2,500 



meter (mean 



sea level) 



2,501-5,000 



meter (mean 



sea level) 



Above 5,000 



meter (mean 



sea level) 



Maximum velocity (to tenths) 



Direction (16 points) 



Altitude (mean sea level) to nearest 10 meters. 



Date -- -- 



Time 



In addition to the above monthly data, similar data for the year, 

 as a whole, as determined from the 12 monthly records, are also to be 

 entered on a blank Form No. 1113-Aer. and forwarded with other 

 forms for the month of December. Copies of the monthly values 

 from which the yearly data are to be determined, must, therefore, be 

 retained each month in the station files. 



138. Forms No. lll^A-Aer. and IIUB-Aer. are designed for the 

 monthly tabulation of the upper air wind data for specific levels above 

 sea level in the code used on punch cards. Separate forms are em- 

 ployed for each of the four scheduled observation times. Form No. 

 1114A-Aer. provides for entries for all levels up to and including 10 

 kUometers; while Form No. 1114B-Aer. provides for such entries at 

 11 kilometers and above. The data entered on these forms are taken 

 from Form No. 1115-Aer., the directions are recorded in code corre- 

 sponding to the 16 compass points and the velocities to the nearest 

 whole meter per second. (See instructions for coding under Form No. 

 1113-Aer. above.) The station number (first column) is to be entered 

 for each observation. This will be taken from the list of index num- 

 bers appearing in the 1939 Weather Code (numeral system). In the 

 second column the number of the month is to be entered as a two- 

 digit figure, i. e., January is to be designated by 01, February by 02, 

 December by 12, etc. In the year column the last two digits of the 

 year are to be entered i. e., for 1939 enter 39, for 1940, enter 40, etc. 

 In the time column, the time of the observation is to be entered to the 

 nearest hour (using the 24-hour system) seventy-fifth meridian time. 

 Thus an observation made at 2:50 p. m. one hundred and fifth meridian 

 time will be coded as 17 (2:50 p. m. one hundred and fifth meridian 

 time converted to seventy-fifth meridian time becomes 4:50 p. m. — 

 the nearest hour is 5:00 p. m. or 17 on the 24-hour clock). When no 

 ascension is made the word "None" followed by the reason for no ob- 

 servation will be entered in the appropriate space as follows: "None — 

 Low clouds," "None — Rain," etc. (surface wind data should be 

 omitted in such cases). "No observation" entries are not to be made, 

 however, if a delayed (more than 1 hour after the scheduled time) 

 observation is made which can be entered on the form. Delayed ob- 

 servations are to be entered on Form No. 1114A-Aer. for the nearest 

 scheduled time, unless this would result in two entries for the same 

 date, in which case the delayed observation is not to be entered. 



