 Thank you for inviting me to this wonderful celebration Nimbus of course is very dear to me because I began my professional career here in 1966 with the Nimbus program and a lot of people in the Nimbus program like Bill Nordberg, Harry Press, Bill Bandeen and others were professional fathers to me. I grew up with Nimbus and it was exciting and Nimbus and NASA, especially NASA Goddard as well as my own organization, ESA, which is not an oil company. It was the old NOAA gave me lots of opportunities as a young scientist, so I thank everyone for that. The course of Nimbus program, as has been mentioned earlier, is instrumental in flying the oops, did I do something wrong here? Yeah, instrumental in flying the very first instruments for atmospheric sounding on the Nimbus 3 satellite and that, as you'll see, has turned out to absolutely revolutionize weather forecasting as we know it today. It began with these instruments and this is sort of a chronology of the sounding milestones in the Nimbus program, but I want to point out Nimbus B here, which was the one mentioned earlier that fell into the drink, was a launch failure and what happened remarkably, as a result of that, was that the Nimbus program under Harry Press decided that, hey, this is so important that we can't, we got to get Nimbus B up there as soon as we can, and they vowed to get a Nimbus replacement, Nimbus B2, up there in less than a year from the date it was launched, which was in May of 1968 and sure enough, this is something that couldn't be done today, but 11 months later in April of 1969, Nimbus B2, which became, of course, in orbit, Nimbus 3, was launched successfully and that was the beginning of the satellite sounding program in space and there are a lot of pioneers that I have on this chart here. I'm not going to go into all of them, but of course, for this lecture, most notably were these two guys, David Wark, Dr. David Wark, who was with this organization, ESA, and of course Rudolph Hanno, who flew all these instruments to more planets than anybody else. I also had an instrument on the Nimbus 3 spacecraft. The Wark instrument was a grading spectrometer that measured the radiation at eight optimally defined wavelengths to observe atmospheric temperature profiling and from the window region all the way to the center of a absorption band due to CO2, which allowed you to relate this spectral variation of radiance to the temperature variation in the atmosphere. If I turn that slide sideways, you would see the temperature profile of the atmosphere being warm near the surface, going to a minimum at the tropopause and then increasing again, going higher in the atmosphere and that was the concept. Rudolph Hanno flew this interferometer, which measured many spectral channels, hundreds of spectral channels compared to just those eight. At that time, we didn't realize how valuable that was. Today, we're flying these kinds of instruments on our operational satellites, so I'll show you in a moment. But these two gentlemen, Rudy, who's shown here, he's still with us. He was at the 45th anniversary. I'm sorry, he didn't make it to this one and his iris instrument and oops. David Wark. We passed away some time ago, but with his Sears instrument, which provided the very first atmospheric temperature sounding back in on the launch day of 1960-69 April 14th as compared to a balloon sound. You can see a very close agreement which gave everybody a lot of excitement. Now, here's something that's really quite interesting. Hal Wolf worked for the National Meteorological Center with me. I'm producing the algorithm and the software to process the Sears data. Of course, on launch day, Ralph Shapiro, who's running the ground station, I was pestering him. I think I was in the ground station all the time watching the data come out on the strip recorders and couldn't wait to get my hands on the data, provided us with tapes of the data for the entire day of that first day and Hal Wolf of NMC and I stayed up all night, that very first night, and processed these data and hand-plotted these data, these sounding data on a chart and hand-analyzed them, a contoured analysis. We got very excited about what we saw. The very next morning, about eight o'clock in the morning, right after the director of NMC, the National Meteorological Center, got in his office. We were there waiting for him. That was Fred Schumann and said, we got some exciting results to show you. He was kind of a skeptic that you could sound the atmosphere from space. He said, okay, let me call my deputies. He called Ed Fawcett, his deputy and Harlan Saylor, his director of operations in, to look at these maps that we created. Harlan Saylor was really a skeptic. He used to needle me on, why am I wasting my time on this business? But he says, let me see those charts. He took those charts and took a look at them, you know, and he looked at them and looked, stared at them, and he went right to one position, ran his finger down there, and he goes, oh my God. And I said, oh, what's wrong? He says, well, he says, we've been taking a lot of flak from the airlines getting calls overnight on our bad weather forecasts. We mispositioned the jet stream and the airlines were flying into headwinds and had to stop, you know, midway to refuel and costing them a lot of money. And here I see that you, that Sears, the Nimbus satellite, properly positioned that jet stream. And then he went on to say, he said, when can you make this operational? This is the very first day, the day after the launch. And of course, my and my naivety and youth and so on, said, oh, we can do it in about six weeks. And he says, great. He says, listen, let's do it. And so we are committed to do that. And through Ralph, Ralph Shapiro, who is running the ground station, played a big role in being able to get the digital data to us from Nimbus on a routine basis. And we started with a carrier transporting tapes from the ground station to Suitland on a almost on an orbital basis to make this happen. And that started on May 22nd, less than six weeks after after lunch. And that was in time for the National Meteorological Center to get these data into their final analysis, which was used for weather forecasting. And it was quite an achievement. And this just shows an example of one test of how these data were improving weather forecasts for the US. This is data over the Pacific, the mid-Pacific, where the Nimbus data showed a cutoff low. You see this low up here and then another low to the south. This is cut off from the one to the north, whereas the analysis without the satellite data didn't show that at all. It's just a diffuse trough. And that made a huge difference. Oops, lost a slide there. That made a huge difference for the forecast for the Western United States three days later. This is a three-day forecast and you see that this is the verifying analysis. And you can see that with the Nimbus data correctly forecast the shortwave ridge over the Western United States, which was not forecast without the Nimbus data. And in fact the errors were more than twice as great without the data than with the data in the forecast errors. Of course that leads to precipitation forecast errors and everything else. But the satellite data wasn't perfect by any means. These instruments, Sears and Iris, had large fields of use. So a lot of cloud contamination and the cloudy soundings quite frankly were pretty poor compared to the clear air soundings. So that problem had to be dealt with. So on Nimbus 5 and Nimbus 6, we flew different kind of instruments. They were multi-spectral radiometers rather than these grading and interferometer spectrometers. But they had the characteristic of being very high spatial resolution, 20 kilometers compared to 150 kilometers. And that pretty much solved the cloud problem in the infrared. We were able to look through breaks in the clouds and see lots of clear, clear sky. And so the yield and the accuracy of the soundings got much much better with these instruments. And then we also flew microwave instruments on Nimbus 5 and 6, which were able to go through clouds. The other thing that happened was in 1998, we flew an advanced microwave sounding unit, which added a lot of spectral channels of temperature and water vapor in the microwave. And this really advanced sounding accuracy quite a bit as well. And so we see here where the temperature accuracy is getting down in the one and a half degree level here from two and a half to three degrees before that. And the problem though with these soundings, with the early Nimbus soundings and even these soundings with the advanced microwave system, is the lack of vertical resolution. Because the energy comes from such a deep layer of the atmosphere, the soundings from the satellite were very smooth compared to the detailed structure that exists due to fronts and the tropopause and so on, that's measured by a balloon. So something had to be done to alleviate this vertical resolution deficiency. So that began in the mid-1980s, supported by the EOS program, and I'll give Shelby Telford a lot of credit for supporting our work in this area. We developed a methodology of hyperspectral sounding. Instead of having just a couple dozen of channels for sounding the atmosphere, we observed the whole spectrum with high resolution, very high resolution, like shown here. Thousands of spectral channels, which together with the large number of channels together with the details of the spectrum that are measured here, led to a big increase improvement in vertical resolving power. It wasn't that the weighting functions or the resolution of a single measurement was all that much better than the older instruments. The fact that you had thousands of these channels, that when you put it into the retrieval system, you had very high signal-to-noise ratio for this deconvolution process of transforming radiance in the atmospheric profiles. And this led to a factor of three to four improvement in the vertical resolution of these soundings. In fact, the hyperspectral sounding information content as was shown from real data once we started flying these instruments, like on the the Ares instrument, on the Aqua satellite, and the IAASI instrument, on the MEDOP satellite, and now the Chris instrument on the SMPP satellite, showed this much greater improvement, three to four times higher information content than these old multi-spectral instruments, and almost as much information as the radio sound. And so this has led to a dramatic improvement in weather forecasting, as shown here by ECMWF, which is the European Center for Medium Range Weather Prediction, where they show that the satellite sounding systems, the microwave and the hyperspectral infrared, are the biggest contributors to the weather forecast now, much greater than, say, the radio sound. In other words, the forecast accuracy degrades the most if you exclude these these instruments from it. And to go on further, that when you look at single instruments, individual microwave and hyperspectral instruments, the hyperspectral infrared instruments are way beyond the capability of the other data sources for improving the weather forecast. In fact, the single most important instrument in today's operation is the MEDOP IAASI, which has almost 9,000 spectral channels to it. And a practical example of this was the Superstorm Hurricane Sandy prediction. You remember that, October of 2012, which landfalled in New Jersey and just devastated the northeast coast. And this was a five-day forecast by the European Center using all the data, including all the hyperspectral sounding data, and of course every other observation that goes into the Global Observing System. And that forecast was spot-on at five days out with what actually occurred, which is this verifying analysis. When they took out the satellite sounding data, this was the forecast. It never even made landfall. And so you can see that the satellite data is playing a very dramatic role for improving not only weather prediction, but the severe storm prediction, such as the Syracan forecast. And the next observing system with the WML caused the space component for 2025. It's going to have at least nine of these hyperspectral sounders in orbit. It's going to have six of them, at least six, on geostationary satellites around the globe. And we're going to have at least three of these in orbits and complementary orbital planes on the polar system. And so thank you for your attention and bearing through the problem with the PowerPoint slides. But I hope the presentation gave you a sense that the Nimbus Satellite Program really did initiate the revolutionary advances achieved in weather forecasting that we enjoy today. Thank you very much for your attention.