PREPARATION OF CHARTS Bos9 
4, Plotting Data on Adiabatic Charts. After the required computations 
have been completed in the data blocks, the computed values are plotted 
on the adiabatic charts. 
4.1 Pressure. Draw a level across the adiabatic chart, from the ex- 
treme left edge of the left margin tothe extreme right vertical temper- 
ature line, at a point corresponding to the surface pressure entered on 
the first line of Data Block A under the caption ''Pressure, mb."' Label 
this level in the left margin '"Sfc-1." 
Draw levels across the adiabatic chart, from the extreme left edge of 
the left margin to the extreme right vertical temperature line, at the 
pressures of significant levels and number them inthe left margin (note 
that the level at the surface has been numbered 1). Levels placed in 
strata of missing data (see J B4-6.6 (e)) willbe drawn approximately mid- 
way between the upper and lower significant levels bounding the strata. 
Whenever the observation extends to a pressure lower than 400 mb., the 
highest levelonWBAN-31A must be plotted as the lowest level on WBAN- 
31B. Similarly, the highest level on WBAN-31B must be plotted as the 
lowest level on WBAN-31C. Whenever the observation extends to pres- 
sures less than 10 mb, data for the replotted level (at or between 12.5 and 
10 mb) and up to 1 mb will be plotted on the same WBAN-31C used for 
the 125 to 10 mb range. The pressure lines pertaining to the replotted 
level and up to 1 mb will be drawn and numbered in red. 
4.2 Temperature. On each significant level, plot the corresponding 
temperature to degrees and tenths and connect each successive point with 
a solid straight line. Whenever the observation extends to pressure less 
than 10 mb, data for the replotted level (at or between 12.5 and 10 mb ) 
to 1 mb will be plotted on the same WBAN-31C used for the 125 to 10 
mb range. The temperature curve pertaining to the replotted level to 
1 mb range will be drawn in red. Curves through strata of doubtful data 
will be drawn as solidlines. Temperature curves will be drawn as dashed 
lines through strata whose data are classifiedas missing. For this pur- 
pose it will be assumed that the temperature lapse rate is represented 
by a straight line between the two known temperature values bounding 
the missing portion. If data onthe recorder record make the selection of 
a level exactly at 400, 100 or 10 mb inconvenient or impossible, the 
temperature at 400 and 100 mb and humidity at 400 mb will be taken 
from the overlap portion of the following chart. The temperature at 10 mb 
will be taken from the overlap portion of WBAN-31C. A dot will be 
placed on the 400, 100 and 10 mbportion of the chart, as appropriate, to 
represent the data at those points. The respective curves on WBAN-31( ) 
will then be drawn to these points as though they were plotted ona 
1-1-69 FMH#3 
