Scientific Study of Unidentified Flying Objects (the Condon Report, complete, three volumes)

duct between C33 and 1,007 m. with a gradient of -297 km-l~ a 3.2 0
elevated inversion is r~ported through this layer. A strong inversion
layer evidently formed during the nigl't and was "1 ifted" to the 8:)3 m.
level by solar heating after sunrise at abol1t 0500 LST.
The Bisr.'arck profilE- for 2100 L:=';' :; hugust (Fig, 4 shows a
I, zoe temperature inversion between the surface ,ill;! the IO';) m, level,
the resulting layer forming a radio ~uct with a refractivity gradient
of -182 km- 1 . It j'5 noteworthy that the Bism8TcK sig'ltings show more
evidence of optical i~veTsion-layer effects than the Rapid Cit) sightings.
In summary, the Rapid Ci ty_· Bismarck sightings arpear to have been
cal~sed by ~. combination of (1) stals seen through an inversion layer,
(2) at least one meteor, (3) AP eewes on a Gel radar, and (!oJ pos-
sible ghost echoes on the Gel radar and malfunction of an airborne
radar gUllsight (althcmgh the commanding officer of the Rapid City de-
tachment I\'as Jater skep':ical that t!'Cl'C had il) fact ever l)cen even a ghost
echo present on the Gel radar).
Case 5*. Louisiana-Texas (l:t. Wo!"~.h) area, 19 September 1957,
sometime between midnight: and 0300 LST.
·I1H.~ weather I-HiS clear. The radio refr, ":U vo index pro"i les for H. Worth,
for 1730 and 0530 LST, 18-19 September 1957, are shown ;.n Figs. 7 and 8.
'~e aircraft was flying at an altitude letween 30,000 rnd 35,000 ft. as
recalled 10 years later by the witnesses involved. l~erc was a slight
temperature inversion at an altitude of 34,()()(l ft., which may have bf!en
associated with a jet stream to the nortl1.
There is a possibility that a very thin, illtcn~c te.nperature
inversion was I)l'csent that: night over certain local ized areas ~H ,1n
altitude of about j4.000 ft .• n layer capable of giving :~trung reflections
at both radar and opti cal frequenc i es. There arc many ,,',;w\.:ts of the
visllal appearance of the UFO that arc ~trrmgly suggcstivl;> of optir.nl
phenomena: the bright, \.;hite light without apparent su"~;t(fnce. the
"'Casp.s refer't'eu to thusly are found in Scctlo:1 IV.
?O 3
duct between 833 and 1,007 m. with a gradient of -297 km-I, 3 3.2"
elevated inversion is l''''ported through this l<lycr. A strong inversion
layer evidently formed during the nigl~t and was "1 if ted" to the S:):) m.
level by solar heating after sunrise at al)()'lt 0500 LST.
The Bisf.·(Jrck profi 1t for 2100 L:=';' :, l\ugu5t (fig. 4 shows a
1, zoe temperature inversion between the surface ,lid the 109 m. level,
the resulting layer forming a radio ('uct with a refractivity gradiont
of -182 km- 1 . It i-; noteworthy that the BismncK sig:ltings show more
evidence of optical i~vcrsion-layer effects than the Rapid Cit} sightings.
In summary, the Rapid City-,Bismarck sightings appear to have been
cal~sed by (" combination of (1) stals secn through an inversion layer,
(2) at least one meteor, (3) AP eewes on a Gel radar, and (1;) pos-
sible ghost echoes on the Gel radar and malfunction of an airborne
rada1' gunsight lalth~)ugh tl1e commanding officer of the Rapid City de-
tachment was Jater sLep':ical thot tl'cre had i'l fact ever I,)cen even a ghost
echo present on the GCI radar).
Case 5*. Louisian,l-Tcxas (I:t. 11'01':.1\) arL!i1, I ~J September 1957,
sometime between midnigh~ 8m! 0300 lSI'.
I1w weather \,a5 clear. 111e radio refr. ','tivc index prc,'iles for l't. Worth,
for li30 and 0530 LST, 18-19 September 1957, are sh()wfJ I,ll l.igs. 7 and S.
The aircraft was flying at an altitude letween 30,000 ,'nd 35,000 ft. as
recalled 10 years later by the witnesses involved. 'J1wro was a slight
ten~erature inversion at nn altitude of 34,000 ft., ~lich may have h~en
associated with fi jet stream to the north.
There is a possibj Ii ty that a very thin, illten~c te,nperature
inversion was present that: night over cortain local ized dreas :n 1'n
altitude of about 3,I,OO{) ft., fl layer capable of glvill~: !~trong reflections
at bOLh radar and optical frequ<.:!nci<.:!s. Tl.erc are J1l:l11Y ,,'';Wi:ts of t\1c'
visllal (lpp('arcmc~' of the UFO that arc "'trrmgly 5ugg(~5t:iv'" oj" opti\",Oll
phenomena: thr.l hr,igJlt, \;111t(, light wi thout apparent Su"'.tilllce, tile
·CIlSP.S refeneu to thusly are found in Sectll);1 JV.