Bs-12 PREPARATION OF CHARTS 
portion of the flight where the humidity is to be terminated 
(see J§B4-6.7) the top of the missing portion will be labeled, 
RH-M, where the temperature becomes -40.0°C. (see Fig. 
B5-4). 
eo : a oe 
TNT Hee NSP IN Ee aE : 
SUN UULN UNCC : 
ell Nu = i aoe NEL 
aw 
i@ay 
em, 
6 hen 
IDs IBS 2 Go beta RH Curve at End of Missing | RH 
5. Mean Temperature of Stratum. A stratum, in this instance, is de- 
fined as that layer bounded by the standardisobaric surfaces listed in 
Table 7 and printed as heavy horizontal lines on WBAN-31( ), and as the 
layer bounded by the surface level and the first standard isobaric surface 
and the layer bounded by the last standardisobaric surface and the ter- 
mination level. Estimate the mean temperature ofeach stratum by laying 
a transparent straight edge over the temperature curve on the adiabatic 
chart. The straight edge should be kept parallel to the vertical tempera- 
ture lines and moved from left to right until the edge intersecting the 
temperature curve produces equal areas to the left and right of it. These 
areas will be bounded by the straight edge, segments of the temperature 
curve, and the isobaric surfaces bounding the stratum. When the straight 
edge has been adjusted to provide for equalareas, draw a 1/4 inch ver- 
tical dash along the side of the straight edge and near the middle of the 
stratum. The mean temperature of missing portions of the record will 
be estimated by assuming that the temperature lapse rate is represented 
by the dashed straight line between the two known temperature values 
bounding the missing portion. 
In a stratum having a uniform lapse rate, the mean temperature would 
be indicated slightly above the midpoint of the stratum; that is, slightly 
above the middle pressure of the stratum. For example, uniform between 
500 and 400 mb., the mean temperature would be at the point where the 
temperature curve crosses 447 mb. 
aS) FMH#3 
