PROJECT BLUE BOOK

tyre UFOB INDEX CARD AISS-UFOB=372-55

1. DATE 2. LOCATION i 112. CONCLUSIONS eS
7? O Wes Balloon
2% October 1955 Minneapolis, Minnesota GO Probably Balloon
| 3. DATE-TIME GROUP 4. TYPE OF OBSERVATION O Possibly Balloon
| Local O Ground- Vi sual EX Ground-Roder = Prcbolls Aiceralé
£
cut 21 /02002 ani 22 /ounes B airVisuol PF Ainiietorcees Rader |O Possibly Aircroft
5. PHOTOS 6. SOURCE Q Was Astronomical
0 Yes ; , QO Probably Astronomical
OXNo ete Military O Possibly Astronomical |
7. LENGTH OF OBSERVATION: -. 8. NUMBER OF OBJECTS | 9 COURSE. - Other Le Phat Vb
f Hlectronic«15 te 20 seconds One (possible aa ete pireniecsgee— ppatiie re mci Hd
: Visuale 2 seconds . medion edie Erratis etek
10. BRIEF See OP SIGHTING aE i sit ek Vt. COMMENTS.
Bes eae “aes 8

jireddssosaiossOuliaes, enaiie® then pea,
estimated to be at 7 milee distence. In 15
20 seconds it appeared te be at 15 miles.

Qound-electronic==Object estinated to be going}
Be oe Oe nee

rx -

rT

>
=

. ei ems omen ime
AISOP Form 5 (15 Oct 54)

53 EXPLANATION
43.0 ISOBARS are straight, horizontal brown lines, The heights in feet of the
e 52 pressure surfaces in the U.S. Standard atmosphere are in parenthesis () below
the pressure values on the left.
51 ISOTHERMS (°C) are the straight, equidistant brown lines running diago-
15.5 1 nally upward from left to right.

ORY ADIABATS are the slightly curved brown lines that intersect the 1000 mb.

e a isobar at intervals of 2°C, and run diagonally upward from right to left.
; The Dry Adiabats tor the folded portion of the pressure range are labeled
= 49. with two (2) values. (See below).

SATURATED ADIABATS are the curved green lines that intersect the 1000

48 mb. isobar at intervals of 2°C, diverging upward and tending to become par-
allel to the dry adiabats.

14.5-.
f | Lay SATURATION MIXING RATIO (in gm, per kg.) is represented by dashed green
; ! ! lines. Their values appear at the bottom of diagram.
Ny THICKNESS (in hundreds of geopotential feet) of the layers between the
14.0-,-46 levels 1000, 700, 500, 300, 200, 150 and 100 mb. is represented by num-
sj bers and a graduation along the middle of each layer. The thicknesses are
4s obtained from the virtual temperature curve by the equal-area method, using
g i any straight line as a dividing line.
13.5— “4 HEIGHT in geopotential feet above mean sea level, or station level, of the
Ae 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
ta3 (°F) through the point po (mean sea level or station pressure) on the
; 13.0, pressure scale, and reading the height on the height scale.
i U.S. STANDARD ATMOSPHERE SOUNDING is indicated by a thick brown
" “2 line.
&
7 The saturated adiabats and isopleths of saturation mixing ratio are com-
ioe ioe puted sy use of vapor pressure over a plane water surface at all temperatures.
+ Extension of chart to 50 mb has_been accomplished _by overlap with
’ +40 pressure indicated in brackets, [200] at 400 mb, and [50] at 100 mb.
a ad Dry adiabats for the overlap are labeled in parentheses ( ).
7 T39 APPROXIMATE VIRTUAL TEMPERATURE may be obtained from the formula
G } im =T+ | where, Ty’ is, virtual temperature in °C, T is free air temperature
i-38 in °C, and w is mixing’ ratio in grams/kilogram. For purposes of thickness
| 11.5-4 computation, use the mean temperature of the layer for T and use the
ra 4 mean mixing ratio of the layer for w.
P| | 5 +37 Sounding data will be entered on-two (2) sets of charts. One chart will
Ln include 0300Z and 1500Z soundings; the other 0900Z and 2100Z soundings.
oan 11.0--36 To provide .tweive (12) hour continuity the preceding i500Z or the 21002 |
ail soundings, whichever the case may be, will be entered as a trace of the tem- '
| 7) perature curve without the reproduction of data or circling of any point.
’ w & ads (See AWSM-105-22). yas Pa: ' st
| Rost wo Black dots © along wind scale lines indicate the levels for which wind J
r= 34% data is reported and plotted. The open circles © indicate the mandatory’ :
ui aR 5 pressure leveis at which wind data is giso entered.
~ yo
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