B4-22 RELEASE AND RECORDER RECORD 
Special Note: If the signal does not remain steady long enough to print 
a readable vertical line of the value in question, no value should be as- 
signed. In no case should a line of pen reversal be considered sufficient 
evidence to assign values at this line. 
d. Unstable Temperature Traces. Failure of a component inthe 
radiosonde is the most likely source of unstable temperature 
traces. The resultant data are fluctuating traces with consider- 
able change within and between most of the traces. Whenever 
changes within these traces or whenever abrupt changes in the 
trends of the traces exceed 1°C, the data will be classified 
doubtful. When, in general, these changes exceed 3°C the data 
will be classified as missing. 
7.8 No Evidence of Malfunctioning. Some types of ground and flight 
equipment malfunctioning exhibit little or no evidence on the recorder 
record, These cases, however, do show certain patterns and a knowledge 
of these is very helpful in the classification of the data. 
7.8.1 Leaking Pressure Cell. The inside of the radiosonde pressure cell, 
if constructed properly, is asnear a vacuum as feasible. When the pres- 
sure cell is leaking, air enters the cell. The entrapped air then causes 
the cell to expand more rapidly than it should as the instrument is car- 
ried aloft and, in turn, causes the instrument to record higher contact 
values (lower pressures) than should be indicated. Therefore, as long as 
the lapse rate is positive (temperature cooling with an increase of alti- 
tude) and the pressure cellis leaking, the temperatures will be too warm. 
When this lapse rate reverses itself andbecomes negative (temperature 
warming with an increase of altitude), a leaking pressure cell will cause 
the temperature data to be too cold. This temperature pattern is useful 
in determining approximately where in the flight the effects of a leaking 
pressure cell begins to show up. Another useful tool is the rate of ascent. 
If ascension rates for strata 1 or 2 km in extent are computed (the 
heights above the station for the minute readings on Forms 20 or 21 may 
be used) for the portion of the sounding which appears erroneous and a 
marked increase from one stratum to another occurs and an above 
normal ascensional rate continues thereafter, the pressure data are 
probably questionable. Another, and possibly the best indication that 
incorrect pressures are being received is the recording of data on the 
recorder above the limits of the commutator bar in the form of a con- 
tinuous temperature trace. Whenever, in the best judgment of the ob- 
server, the pressure data are believed tobe incorrect because of a leak- 
ing pressure cell, all data from the beginning of the suspect portion of 
the record will be classified as missing. 
= t=O9) FMH#3 
