Project Jet Stream

Abstract

The importance of "jet streams'' and other near-tropopause phenomena to aircraft operations led to the establishment by the Air Force of a project for probing these regions. Two specially instrumented aircraft, a B-47 jet bomber and a B-29, are the data gathering vehicles. Their instrumentation is discussed and examples of the data gathered thus far are given. These data show that significant maxima and minima of wind speed can occur between reporting stations and indicate that at jet stream levels, the gradient wind is a much better approximation to observed space-averaged winds than the geostrophic.t Entered as second class matter September 24, 1945, at the Post Office at Lancaster, Pennsylvania, under the Act of August 24, 1912. Acceptance for mailing at special rate of postage provided for in paragraph (d-2), section 34.40, P. L. and R. of 1948of , authorized September 24, 1945 Address all business communications, purchase orders and inquiries regarding the Society to the Executive Secretary, 3 Joy Street, Boston 8, Mass. See inside back cover for complete information regarding publications, officers and activities of the Society.143 Downloaded from http://journals.ametsoc.org/

Analysis of Some “Project Jet Stream” Data

“…All three of these small maxima were evident in the data at both the 400 and 300 mb levels, therefore their existence cannot be denied. In the "Project Jet Stream" article [1], their FIGURES 3 and 10, this same sort of thing appears in the wind data gathered by the Project's B-47.…”

“…T HE lead article in the April 1954 issue of the Bulletin of the A. M. S., entitled "Project Jet Stream" [1], dealt principally with data obtained by a B-47 jet bomber based at MacDill AFB, Tampa, Fla. The present study deals exclusively with data obtained by the Project's B-29 based at Patrick AFB, Cocoa, Fla.…”

Meteorological Satellites and Weather Reconnaissance Aircraft—Complementary Observing Systems1

“…Ways of deducing wind velocity from a satellite are practically non-existent. 10 The aircraft can, on the other hand, make excellent wind measurements at its flight altitude, using Doppler radar or other techniques 8 (Endlich et al, 1954;Endlich and Rados, 1959;Rados, 1960) ; in spite of extensive development efforts, no satisfactory system for obtaining accurate wind data below the aircraft is yet available.…”

“…15 shows the cloud data available for wind field deductions from a TIROS picture of a cold front, jet stream case over the North Atlantic on 4 April 1960 (from Widger, 1960b). The charts in the figure illustrate the detailed wind data obtained from a perhaps similar jet stream by the Project Jet Stream aircraft (Endlich et al, 1954). In Fig.…”

“…At flight level, aircraft are able to make relatively precise turbulence measurements (Endlich et al, 1954;Rados, 1960 have, of course, no way to make direct measurements of this parameter and even the deductions from cloud type data are severely limited by considerations of resolution.…”