One fateful, sunny day in 1974 or 1975, while walking by "Lake Ludicke" in front of Bldg. 183, I ran into Jim Johnston, who had a proposition for me. Jim managed the section containing the Ground-Based Microwave Applications Group (GBMA), which provided engineering support for Division 32's Radio Astronomy Group (RAG) to which I belonged (I had recently handed over leadership of the group to Sam Gulkis).  Jim asked if I would direct an effort to find useful applications for an engineering model of the Nimbus 6 satellite instrument called SCAMS (SCAnning Microwave Spectrometer), which was built in his Section.  Whereas JPL was in charge of unmanned exploration of the solar system, Goddard Space Flight Center (GSFC) was in charge of Earth-orbiting, downward-looking satellites.  GSFC had contracted with JPL to build SCAMS, and apparently they forgot that the SCAMS engineering model existed, and was at JPL.  I suspect that JPL didn't ask GSFC if they wanted SCAMS turned over to them as provided by the contractual agreement.

The SCAMS was a combination water vapor radiometer (WVR) and microwave temperature profiler (MTP), designed for the down-looking geometry of a satellite.  Joe Waters, who was in Johnston's section, had started field observations with SCAMS, but was too busy with other tasks.  I consented, provided it didn't interfere with my moon studies and preparations for using the Table Mountain Radio Astronomy Observatory (TMRAO).  When I met with Joe Waters (April, 1975) I stipulated that I would work with the SCAMS only for as long as that work was either benign or beneficial to mankind - spoken with the bravado of a young idealist who was confident of employment.  After all, this was still like the 60's, and for scientists and engineers in the space biz, all trends were upward.  In just a few transition weeks I was in charge of the ground-based SCAMS applications.

Ever so slowly I became interested in using the SCAMS for new meteorology research and practical applications, and I secured funding for doing this. The GBMA provided field support, and made hardware modifications.  As my SCAMS work grew to about half time, Mous Chahine, my Section 325 manager [who later became JPL's Chief Scientist], was concerned that I was allowing my radio astronomy activity to be crowded out by the ground-based meteorology work, and he suggested I decide which career path to emphasize.  The GBMA's group supervisor (GS), Nob Yamane, suggested I move to his group where I would be welcome to continue my moon work.  We both could see the advantage in this arrangement since I could be closer to the people doing hardware construction and field operations, and by being in the GBMA I would have a greater interest in strenghtening the group's viability by creating new work for the group. I switched to the GBMA group in 1978, and began spending ~2/3 of my time with ground-based microwave radiometers for atmospheric studies.

The idea for the Microwave Temperature Profiler, MTP, occurred to me during a July, 1977 flight to Mexico City.  I recall looking at the cirrus clouds outside the airplane window and wondering what the vertical gradient of temperature was within them. Those thoughts were a small extrapolation of the ground-based work I had been doing with marine stratus clouds.  I remember sitting in my brother-in-law's living room sketching how an airborne version of the ground-based temperature sounder instrument might work. By coincidence, at about this same time JPL middle level management assigned Gary Reisdorf to full-time marketing of ideas by members of the JPL Division I was in.  When he contacted me in December, 1977 to ask if I had any ideas that could be marketed, I described my airborne version of the ground-based temperature profiler. Reisdorf and I flew to Washington, DC on a marketing trip, and on January 26, 1978 we met with a FAA aviation safety program manager for discussions of using an airborne temperature profiler to warn of Clear Air Turbulence, CAT. On February 16, 1978, FAA funding for 2 years was verbally approved.  Planning for a CV-990 instrument based on the existing SCAMS was begun before the FAA funds formally arrived (~July) because we had a short schedule for installing in the CV-990 at the end of the year. This was the beginning of a funded MTP.

During my marketing of the MTP, or Temperature Structure Radiometer (TSR) as I called it at that time, I believed that warnings of CAT should be given when lapse rate was close to adiabatic.  I mistakenly thought that the closer to adiabatic the more likely was CAT.  Only after data was in hand, when CAT was associated with inversion layers, where static stability was large, did I realize that in fact CAT should not be generated where the air was adiabatic, since such a layer could not store much vertical wind shear. Indeed, it would be the inversion layers, I eventually reasoned, that should provide the wind contrast energy source for CAT.  This just illustrates that sometimes a good idea can be persuasive for the wrong reasons.  Intuitively, however, I was correct in thinking that the wind field was somehow related to the temperature field, and therefore measuring the temperature field should have CAT predictive value.

I will take credit for intuitively knowing that the temperature field was relevant to CAT generation, and that being able to measure features of the temperature field that had never been measured before was likely to help solve the CAT forecast problem.  As it turned out, it was irrelvant that I had the CAT generation theory backwards when I successfully marketed the idea for building an airborne temperature profiler.  As soon as the data was in, showing that CAT was associated with inversion layers and the tropopause, the airborne instrument was as useful as I had promised in my marketing.  If there's a lesson here, I think it would be that details are less important than an intuitive appreciation of relevant aspects of a problem.  Through a process of successive approximations using experimental results the details will get "sorted out."  The early stages of a new endeavor should stay focused only on the big picture.  Thankfully for MTP, nobody interfered with the marketing of the idea by pointing out that "Gary was 180 degrees backwards in the details of what he was proposing."

For a good article in a popular magazine on the origins of MTP and its early contributions to the "ozone hole" investigations, go to Spacefilght Article on MTP.

This site opened:  October 29, 2003.  Last Update:  October 29, 2003