Introduction

     My name is Michael Duda and I am a student at the University of Colorado at Boulder, where I study computer science. My primary academic interest is in graph algorithms, though I am also interested in mathematical optimization. However, I work at the National Center for Atmospheric Research (NCAR) as a student software engineer, where the primary project that I am involved in deals with numerical weather prediction over the Antarctic. Traditional types of upper-air observations are quite sparse over Antarctica, and consequently, my group has an interest in using GPS radio occultation soundings, like the type that will be available from COSMIC, to improve our forecasts. Because of the potential benefits that radio occultation soundings will bring to our forecasts, I became interested in participating in this field trip when it was first brought to my attention by Dr. Bill Kuo, COSMIC Director. Of course, I quickly found further reasons for wanting to participate in the trip.

     In the three years that I have worked at NCAR, I have gained an appreciation for the field of meteorology, which has observable and physical qualities that are absent in computer science; in particular, numerical weather prediction has caught my attention. Besides the primary project in which I am involved, I have done some work for a cooperative project between NCAR and the Civil Aeronautics Administration of Taiwan, with the partial goal of producing a weather forecasting system to be used by Taiwan's aviation community. Through this project, I was able to learn a small amount about the weather in Taiwan, and in particular, about the importance of typhoon forecasting for many industries in Taiwan. When I learned that part of the field trip would take us to Taiwan, I thought that it would be a great opportunity to see first-hand the research and facilities that are used to do forecasting and to further our collective knowledge in atmospheric science.

     Additionally, it is my belief that a first-hand experience of other cultures can benefit one's opinions and thinking in international matters. My experience has taught me that those people who are well-read are generally more articulate and have well-formulated ideas, and I think that, to some extent, a similar benefit can come from having a broad base of cultural experiences. The mixture of tradition and modern technology in East Asia is very different from the culture that I was raised in, and so further interest in participating in the field trip came from my desire to gain a great international experience.

Scientific Experience

     Having just attended a summer colloquium at NCAR on the topic of atmospheric remote sensing using the global positioning system (GPS), our visits to the institutes and facilities in Japan and Taiwan were very rewarding. Our first visits were in Tsukuba, Japan, where we toured the Geographical Survey Institute (GSI) and the Meteorological Research Institute (MRI). GSI is the institute charged with overseeing the GPS Earth Observation Network (GEONET), which consists of about 1,224 GPS ground stations. Originally, this dense network of stations was conceived as a way to monitor deformation of the earth's crust in Japan for the prediction of seismic events. Now, though, the stations are also used by researchers to do ground-based atmospheric remote sensing. Because of the density of the stations, averaging about 25 km apart, it is possible to do water vapor tomography, which allows researchers to get a three-dimensional image of the water vapor content of the atmosphere.

     Water vapor tomography, as we learned while at MRI on July 5, is just one of many areas of research using the GPS. One of the more interesting applications, at least to me, is the application of precipitable water vapor measurements, derived using the GPS and GEONET, to numerical weather prediction. As described by Dr. Yoshinori Shoji of MRI, water vapor estimates using the GPS can be assimilated into numerical weather models using variational data assimilation techniques. Potentially, this additional data can improve the resulting numerical weather simulations, and, in return, the model output can be used to derive better estimates of water vapor from the original GPS data. This type of feedback I find to be very interesting, and in my mind, it is reminiscent of the approach that can be taken to solve certain classes of problems in computer science and mathematics that have what is known as a dual problem. Additionally, the optimization aspect of variational data assimilation techniques piqued my interest in the assimilation of GPS-derived precipitable water vapor measurements.

     At the Japan Meteorological Agency (JMA) in Tokyo, we learned more about the assimilation of GPS data into one of Japan's weather models, and had the opportunity to observe Japanese meteorologists at work. To my recollection, we learned while at JMA that model simulations conducted in Japan using a three-dimensional variational data assimilation system to ingest GPS observations did not show significant improvements in forecast accuracy; in fact, some statistics presented while we were at MRI showed an overall neutral impact. This was quite surprising to me, as what I had learned during the colloquium would seem to indicate that a more positive impact on forecasts could be obtained. The greater number of observations that will be made available in polar regions by COSMIC/ROCSAT-3 satellites may improve this situation for Japan's global spectral models, and hopefully for our regional models over the Antarctic. Still, it was interesting for me to learn more about the actual influence of GPS data on operational forecasts.

     Near the end of our time in Japan, we had the opportunity to see the Middle and Upper Atmosphere (MU) Radar in Shigaraki, near Kyoto. Quite interestingly, there is only one full-time scientist working at the radar, Dr. Mamoru Yamamoto, who gave us a tour of the facilities. The MU Radar consists of 475 individual antennas that are controlled from a single control center. Rather than employing a single, large radar dish, the array of active antenna elements is more cost effective, and to my mind, is operated in a more clever way: Aiming of the pulsed radar signals that are emitted by the array is accomplished by adjusting the timing and phase of the individual signals leaving each of the array elements. The effect is a large radar pulse that propagates in a chosen direction, which can be up to 30 degrees from the zenith direction. Not knowing much about radar technology, and having only envisioned radar dishes when imagining a radar system, this approach seemed very elegant.

     During the second half of our trip, while we were in Taiwan, we had the pleasure of visiting the Central Weather Bureau, the National Space Program Office, the National Science Council, the National Center for High-Performance Computing, the Space and Remote Sensing Institute, and facilities at the National Central University. After visiting these institutes and the institutes in Japan, my initial impression was that the Japanese and Taiwanese seem to focus on two different approaches to remote sensing using the GPS. While much of the Japanese research is focused on the uses of ground-based GPS, the Taiwanese research makes more utilization of space-based techniques. Perhaps not surprisingly, it is Taiwan that will be launching the ROCSAT-3 satellites, also known as COSMIC, in the States.

     During the colloquium, we learned about the density of observations that will be provided by COSMIC/ROCSAT-3 satellites, and at the integration facility at the National Space Program Office, we had the opportunity to see two of the satellites being built. To see "in person" the satellites that will be providing data that will most likely be assimilated into the models that my group at NCAR runs on a daily basis was fascinating. At the integration facility, we were also shown some of the testing equipment that is used on models of satellites and on the satellites themselves. This equipment checked the ability of the hardware to withstand everything from vibration to temperature changes to depressurization. Although I know almost nothing about satellites or aerospace engineering in general, our visit to the National Space Program Office did help me to understand better the commitment Taiwan has to building its reputation in science.

     Being much closer to my area of knowledge, our visit to the National Center for High-Performance Computing (NCHC) was very educational, and it made clear to me that Taiwan is indeed willing to commit to building the technological infrastructure necessary for the advancement of science in the country. While at the NCHC, we learned about the Taiwan Advanced Research and Education Network (TWAREN), a plan to create a high-speed network connecting about eleven research centers throughout Taiwan. The goal of the project is to promote collaborative research throughout Taiwan, and internationally as well, by reducing the cost of communication and sharing of data between institutions, and to push Taiwan towards the role of being an Internet gateway for East Asia. For me, the specifications of this network were impressive, and I wondered how much benefit a similar network with global coverage could provide to researchers, particularly those who commonly work with large data sets or who could benefit from sharing of computational resources.

     Our visits to the NCHC and other institutes in Japan and Taiwan were very rewarding. Of particular value to me, though, were our visits to the Geographical Survey Institute in Tsukuba, Japan and the National Central University in Taiwan. During these visits, we had the opportunity to hear presentations ranging from several minutes to nearly an hour by scientists and other students regarding their research and studies. These presentations, to me, were valuable in that they gave me a broader look at the applications of GPS remote sensing. During the colloquium, our lectures focused on developing the background and details of retrieving GSP radio occultation soundings, for example. This was informative, but hearing from scientists about how they use GPS data to track things like traveling ionospheric disturbances gave me a more complete idea of the importance of all of the science that we learned about in the colloquium.

     One of the goals of this field trip was to instill in us the desire to collaborate internationally with researchers in East Asia. Whether I eventually find myself doing research in GPS remote sensing or in theoretical computer science, I hope to find collaborators in East Asia as great as those we met throughout this trip. The scientists and students whose work we learned about displayed such excellence that I truly hope I can find such wonderful international collaborators in the future.

Cultural Experience and Personal Interaction

     This field trip represented my first excursion overseas, and although our schedule was quite busy, I am very glad to have been able to gain some impressions of Japanese and Taiwanese culture. What I have seen of East Asian culture, I realize, is only a glimpse, and further travel to Japan and Taiwan would help to provide a more full picture of the cultures in these countries. Still, I have truly enjoyed experiencing the captivating blend of tradition and modern technology that exists in the two countries.

     The strongest impression that I have of the culture in Japan and Taiwan regards the generosity and patience of the people. Since I speak only English, I relied completely upon the ability of our hosts to communicate with me in my native language. Having studied only a small amount of Spanish, I understand that it can be tiresome to force ones' self to speak in another language for any extended period of time. Nonetheless, our hosts patiently gave explanation to us in English, and their willingness to answer our many questions never ceased. This was particularly apparent in Taiwan, where we were guided by eight students from the National Central University. These students accompanied us everywhere we went, and, although they sometimes thought otherwise, I was very impressed with how well they spoke English. Very often, if I helped them to formulate their thoughts in English, they would thank me; the whole time, I thought to myself that it was I who should be thanking them.

     A large part of my experience, too, came through the food that we ate. In Japan, the great majority of the food that we ate, especially at dinners, was sushi. Although I frequently enjoy sushi here in the U. S., I was very pleased to note the exquisite presentation and attention to appearance that was given to the meals in Japan. As I heard one of the other U. S. students say in Japan, our meals were so neatly arranged as to be like works of art. Of course, each of our meals was delicious as well, and in Taiwan in particular, we were able to eat well for what I thought to be very modest prices.

     As a more general observation, it seemed to me that the Taiwanese are more open to outside influence. While we were in Taipei, we were given the opportunity to visit traditional teahouses, old market streets, and temples. But not far from any of these places, we were able to find modern buildings and department stores, many of which looked not too different from those found in Western cities. One particular example of this came while we were in Taipei. Yang Kuo-Feng and Huang Cheng-Yung, two students at National Central University, suggested that we get some coffee. Expecting to visit a small coffee shop where I would need help in ordering, I was surprised to find that we went to a Starbucks. At first, I thought that perhaps this was a sort of courtesy meant to show me something familiar, but after talking with the students amidst sips of coffee, I gained the impression that it was not at all uncommon for students to frequent such places.

     Generally, I was surprised by the openness and acceptance of outside influence that I encountered in Taiwan. Japan differed somewhat from Taiwan in this respect (though I must add that we were fortunate enough to see some of the amazing tradition that exists in Taiwan), and on account of this, I found the Japanese culture to be generally fascinating. Although our time in Japan was packed with visits, we did have the opportunity to see some of the strong tradition that exists in Japan, particularly while in Kyoto, the old capital city. There, we stayed in a traditional Japanese inn, and we had the opportunity to visit the Kinkaku-ji Temple and the Ryoanji Temple, all of which illustrated the traditional Japanese architecture and design that I had always imagined.

Concluding Remarks

     I can, without any qualification, say that this trip was an excellent and memorable experience for me. I was able to see the many applications of GPS remote sensing that extend beyond my initial interest in the technique. In our visits to the many institutes that devote large resources to the further study of GPS atmospheric remote sensing, I find it incredible that the GPS, which was initially intended for positioning and navigation, has been cleverly extended to be of use in sensing properties of the atmosphere. The idea that a whole field of research is based upon an extension of the properties of the GPS is fascinating to me. Better still, while learning about the research that scientists and students are pursuing in this field in East Asia, I had the opportunity to experience a small part of the interesting and unique culture of Japan and Taiwan.

     Of course, this trip would not have been possible without the sponsorship of NSF International Programs and the extensive planning and assistance of many people. I would like to express my gratitute to Bill Kuo, Kim Prinzi-Kimbro and Scott Briggs for making this trip happen, and to Tetsuya Iwabuchi, Annabel Liu, the eight students from National Central University, and the other U. S. participants for making the experience as great as it was.