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EXPLANATION
‘$SOBARS are straight, horizontal brown fines. The heights tn feet of the
pressure surfaces in the U.S. Standard atmosphere are in parenthesis () below
the pressure values on the ieft.
ISOTHERMS (°C) are the straight, equidistant brown Nines running diagomalty upward from teft to right.
.
DRY ADIABATS are the slightly curved brown lines that intersect the 1000 mb.
leober at intervals of 2°C, and run diagonally upward from right to left.
The Dry Adiabats fer the feided portion of the pressure range are labeled
with two (2) values. (See below).
SATURATED ADIABATS are the curved green Hnes that intersect the 1000
mb. isobar at intervals of 2°C, diverging upward and tending to become perallel to the dry ediebets.
SATURATION MIXING RATIO (in gm. per kg.) is represented by dashed green
fines. Their values appear at the bottom of diagram.
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THICKNESS (in hundreds of geopotential feet) of the layers between the
levels 1000, 700, 500, 300, 200, 150 and 100 mb. is represented by numbers and a graduation along the middle of sach layer. The thicknesses are
obtained from the virtuel temperature curve by the equal-area method, using
any straight line as 2 dividing line.
HEIGHT In geopotential feet above mean sea level, or station level, of the
1000 mb. surface is obtained from the nomogram in the upper left-hand
corner by drawing a straight line from the point on the temperature scale
(°F) through the point pp (mean sea level or-station pressure) on the
pressure scale, and reading the height on the height scale.
U.S. STANDARD ATMOSPHERE SOUNDING is indicated by a thick brown
line.
The saturated adiabats and isopleths of saturation mixing ratic are computed by use of vapor pressure over # plane water surface at all temperatures.
Extension of chart to 50 mb _has_been accomplished _by overiap with
pressure indicated in brackets, [200] at 400 mb, and [50] at 100 mb.
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APPROXIMATE VIRTUAL TEMPERATURE may be obtained from the formula
Ty =T+% where T, is virtual temperature in °C, T is free air temperature
in *C, and w is mixing ratio in grams/kilogram. For purposes of thickness
computation, use the mean temperature of the layer for T and use the
mean mixing ratio of the layer for w.
Sounding date will be entered on two (2) sets of charts. One chart will
include 0300Z and 1500Z soundings; the other 0900Z and 2100Z soundings.
To provide twelve (12) hour continuity the preceding 1500Z or the 2100Z
soundings, whichever the case may be, will be entered as 9 trace of the temperature curve without the reproduction of data or circling of any point.
{See AWSM-105-22).
°
1
TT
w
te
NDS
Black dots @ slong wind scale lines indicate the levels for which wind
data is reported and plotted. The open circles © indicate the mandatory
pressure levels at which wind data is also entered.
3
US STANDARD ATMOSPHERE ALTITUDE
THOUSANDS OF METERS
Dry adiabats for the overlap are labeled in parentheses
WIND SCALE
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