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The Roswell Report: Fact versus Fiction in the New Mexico Desert was published by Headquarters United States Air Force in 1995. The Black Vault distributes this copy. It reproduces the report by Col. Richard L. Weaver and the synopsis by 1st Lt. James McAndrew, both written after a General Accounting Office inquiry requested by Representative Steven Schiff. The Air Force search found no evidence of an extraterrestrial craft or crew. It concluded that the Roswell debris most likely came from NYU Flight No. 4, a Project MOGUL balloon train.
“Sea”23 pages
The actual atmospheric distribution, however, does not indicate an adiabatic lapse rate for air but rather a lapse rate which varies with altitude. For the troposphere the lapse rate of the atmosphere averages $ - 1.98^{\circ}\mathrm{C} / 1000 $ ft. It may be shown then that in the troposphere a rising balloon will get warm with respect to the air (neglecting ventilation and radiation effects) at a rate of $ 1.98 - .57 = 1.41^{\circ}\mathrm{C} / 1000 $ ft. In the tropopause the lapse rate of the atmosphere is zero. Thus the lifting gas (if helium) will cool relative to the air at a rate of $ .57^{\circ}\mathrm{C} / 1000 $ ft.
Similarly, in the stratosphere, the lifting gas will cool relative to the air at a rate of 2.24 + .57 = 2.81 $ ^{\circ} \mathrm{C} / 1 0 0 0 $ ft. This effect is plotted as Figure 22.
Figure 22. Lapse rate of air and helium.
Here, below point A, the lifting gas will be warmer than the air. Above point A, the lifting gas will be cooler than the air. The effect of this temperature difference on the lift (as shown in the previous section) is approximately $ \Delta L=1\frac{\Delta T}{1} $
$$
\Delta L = L \frac {\Delta T}{T} \frac {1}{(1 - B)}
$$
Thus, as a balloon system passes through point A, it will have less lift than at release. This effect has been observed on several flights, where a balloon system slowed down during ascent through a temperature inversion.
Since the effect of the sun in heating the lifting gas decreases the effect of different lapse rates, the effect is not as noticeable during the day as at night. At night the balloon system may pass through an inversion, lose its lift, and remain at an altitude much below its estimated floating altitude until warmed by the sun's rays at sunrise. Report, cited by the archive. The PDF is mirrored here; the original link is under it. The text was read from the page images by an OCR model; expect the odd misread word. 882 pages are in the text index: search them above, or from the library's search.