[Doc Ewen looks into the horn antenna, 1950]
Image courtesy of Doc Ewen


Harvard Cyclotron: 1948-1951

Detection of HI Line: 1951

Harvard 24ft and 60ft and NRAO founding: 1952-1956

1950s and 1960s: Two Roads that Crossed

Microwave & Millimeter Wave Applications in the 1970s and 1980s

Mm Wave Radiometry in the 1990s

May 2001 visit to NRAO Green Bank



[Doc Ewen and horn antenna, 2001]
Image courtesy of Doc Ewen

Doc Ewen: The Horn, HI, and Other Events in US Radio Astronomy

by Doc Ewen, © 2003

Microwave and Millimeter Applications in the 1970s and 1980s

Buzzards Bay Bridge - Cape Cod Canal (BC)3

A Personal Perspective

Cal Swift
Department of Electrical and Computer Science, University of Massachusetts
© 2005

The (BC)3 work was published in July 1974, "Microwave radiometer measurements of the Cape Cod Canal" by C.T. Swift, Radio Science, vol 9, pp 641-653. I gave you a reprint a few years ago. This paper reported on (a) the surface roughness / wind speed effect on the ocean emissivity; (b) the bistatic scattering of sun radiation as a function of frequency, surface roughness, and polarization (see also vol 3 of Microwave Remote Sensing by Ulaby, Moore, and Fung, Artech House 1986); (c ) emission from foam must be associated with breaking waves, and not foam streaks; (d) shadowing by the platform can significantly influence the brightness temperature.

The data were highlighted in a review paper, "Passive microwave remote sensing of the ocean-a review", C.T. Swift, Boundary Layer Meteorology, vol 18, (1980) pp. 25-54.

The data were used to help justify post-SeaSat/NIMBUS earth viewing radiometer systems, "Applications review panel report: High resolution passive microwave satellite MIT/RLE", Edited by D.H. Staelin and P.W. Rosenkranz, 14 April 1978 (In Chapter 4: Monitoring the Ocean and Other Aquatories by C.T. Swift and F.Y. Sorrell). Jules Lehman was the NASA headquarters sponsor of the report, and Per Gloerson of NASA Goddard was the contract monitor. Incidentally, Jules Lehman was the headquarters contact for the Buzzard’s Bay bridge project.

After the bridge experiments ended, the Langley activity was continued by proposing that NASA headquarters fund the rebuilding of the Ewen Knight L-Band system as a means to remotely measure ocean salinity from an aircraft. This was successfully achieved in 1976, with the 2-D mapping of the lower Chesapeake Bay. Several more demonstrations using different L-Band instruments were made over the years to finally justify the Aquarius mission which is under development to globally measure salinity from space to an accuracy of .1 - .2 parts per thousand.

Display about the Ewen Knight L-band radiometer that flew on the NASA C-54 in 1976. Photo courtesy of C.T. Swift. (Click thumbnail for larger image)
Cal Swift (right, closest to camera) as a student on a NASA Wallops aircraft. Photo courtesy of C.T. Swift. (Click thumbnail for larger image)

Modified on Monday, 18-Jul-2005 12:38:53 EDT by Ellen Bouton