气象研究所)

气象研究所) Report of Visiting Meteorological Research Institute and University of Nagoya in Japan, April 2-7, 2001 Chung-Chieh Wang Assistant Professor, Department of Environmental Management, Jin-Wen Institute of Technology, Hsin-tien, Taipei, Taiwan, ROC 1. Introduction In order to strengthen our collaboration with other countries in meteorological research, a visit by Professor Tai-Jen Chen of the Department of Atmospheric Sciences, National Taiwan University, and myself to Japan was scheduled from April 2 to 7, 2001. Two institutes, the Meteorological Research Institute (MRI, 氣象研究所) of the Japan Meteorological Agency (JMA, 日本氣象廳) at Tsukuba (筑波), Ibaraki (茨城縣) and the Institute for Hydrospheric-Atmospheric Sciences (大氣水圈科學研究所) of the Nagoya University (名古 屋大學), Nagoya, both internationally renowned for their leading research efforts, were included in our visit. The reasons for our visit are three fold: First, to learn about the research focus in mesoscale meteorology at these institutes in Japan; second, to interact with Japanese scientists and to exchange ideas for research; and third, to meet and establish connections with researchers in Japan for possible future collaboration both in research on topics of mutual interest, and in coordinated field experiments that are beneficial to both sides. The arrangement for our stay in Japan is as the following: Travel from Taipei to Tsukuba on April 2, visit MRI for the entire days on April 3 and 4, visit MRI again in the morning and travel from Tsukuba to Nagoya in the afternoon of April 5, visit the Institute for Hydrospheric-Atmospheric Sciences of the Nagoya University on April 6, and finally travel from Nagoya back to Taipei in the morning of April 7. Therefore, a total of three and half days were spent on meeting and interacting with Japanese scientists, while among them two and half days were at MRI and one day was at Nagoya University. At these two locations our presentation was given in the afternoon of April 3 and 6, respectively. Initially we planned to also visit Tsukuba University on April 5, but all the faculty members were out of town for scholarly activities of their own during the spring vacation. Professor Chen then decided to spend another morning at MRI to meet with some more people. 2. Visit the Meteorological Research Institute (MRI) The MRI of the JMA is located inside the Tsukuba Science City (筑波科學城) in Tsukuba, Ibaraki, Japan, and is about 2 hours to the northeast of Tokyo (東京) by bus. During our visit to MRI we met with researchers in the first lab (meso-modeling group, on April 3) and second lab (GPS-meteorology group, on April 4 and 5) of the Forecast Research Department (預報研究部), and those in the Typhoon Research Department (颱風研究部, on April 4). The following is a detailed description of our activities during the visit, arranged by dates. Through these activities we learned about the ongoing research efforts in mesoscale meteorology at JMA, exchanged ideas with JMA scientists, and discussed the possibility of further interactions in the future. April 3 (9:50 am to 5:45 pm) In the morning of April 3, Professor Chen and I met with scientists in the First Lab of the Forecast Research Department at MRI. The head of this lab is Dr. Masanori Yoshizaki (吉崎 正憲) and researchers include Dr. Teruyuki Kato (加藤 輝之), Hisaki Eito (永戶 久喜), Chiashi Muroi (室井), Hirotata Kanehisa (金久 博忠). Their research mainly focuses on mesoscale phenomena occurred near Japan, especially during winter and the Baiu season (the equivalence of Mei-Yu season in Japan). Dr. Yoshizaki introduced the “Winter MCSs Observations over the Japan Sea---2001” field experiment supported by the Japan Science and Technology Corporation---Core Research for Evolutional Science and Technology (JST-CREST) project (10:00 to 10:50 am). The objectives of this experiment are 1) to investigate the Japan polar-airmass convergence zone (JPCZ), polar lows, mesoscale vortex and winter MCSs, and 2) to elucidate the mechanisms for the formation and development of winter MCSs through the use of numerical model. Through the use of 7 Doppler radars, 4 boundary layer radars, and 5 soundings near the Noto Peninsula of the Chugoku (本州) area, as well as 3 ships and several airplanes over the Japan Sea, data were collected in December 2000 and January 2001, including two intensive observing periods (IOPs) in January 12-19 and 24 January-1 February of 2001. Similar field campaigns were also carried out during the cold season and Baiu season (X-BAIU) in 1998, 1999 and 2000. An experiment is currently being planned for the Baiu season this year with two IOPs scheduled tentatively from 11 to 18 June and from 24 June to 1 July to collect data west of the Kyushu Island over the East China Sea. Dr. Kato (10:50 to 11:45 am) presented results of numerical simulations using the MRI non-hydrostatic model (NHM) on the JPCZ and the development of a mesoscale vortex over the Japan Sea observed on 14 and 15 January this year, during IOP-1 of “Winter MCSs Observations over the Japan Sea---2001” just introduced by Dr. Yoshizaki. The MRI NHM is a primitive equation (PE) based non-hydrostatic model, and was mainly developed by Dr. Kazuo Saito (齊藤 和雄) who is currently at JMA. The simulation was performed at horizontal and vertical resolutions of 5 km (300 ， 300 grid-points over an area of 1500 ， 1500 2km) and 38 layers, while the initial fields were outputs of the JMA Global Spectral Model (GSM, T213/L40) and Regional Spectral Model (RSM, at 20 km resolution and 36 layers). The model realistically captured the northerly cold air outbreak, cloud street development over the Japan Sea, and the precipitation over coastal regions of Japan, and the result was in very good agreement with the observations. We exchanged opinions on the mechanisms for the development of mesoscale vortices along the JPCZ. Dr. Kato also slowed results of MRI NHM simulations of another vortex case occurred on January 20, 2000 under similar synoptic conditions at 1 km resolution. After the discussion, Professor Chen expressed interests in visiting MRI again to join the weather briefing discussion and experience the operation during the IOP periods of the winter MCSs observation experiment in 2002, scheduled to be between 15 January and 2 February. After lunch with Dr. Yoshizaki, the colloquium of our invited presentations was held from 2:00 to 4:30. Professor Chen first gave a talk entitled “Case Study of a Summertime Hailstorm Occurred in the Taipei Basin,” and drew discussion on several aspects such as the reason for individual convection cells to form as a squall line, and formation mechanism of the mesovortex, etc. Then, I spoke with the topic “Case Study of the Leeside Mesolow and Mesocyclone in TAMEX,” and issues discussed included formation mechanisms of cyclones at the leeside of mountains of different size, and possible mechanisms for the formation of mesoscale vortex observed, etc. After the colloquium, we met with Dr. Tom Zhu (祝從文) of the Typhoon Research Department from Mainland China, and we talked about the current status of meteorological research in China, and the potential problems with the QuikSCAT satellite derived ocean wind data (4:30 to 5:00 pm). Mr. Eito also showed us his recent work on the simulation of cloud streets to the southwest of the Kyushu Island (九州) during an event of cold air outbreak (5:00 to 5:45 pm). The MRI NHM simulation was quite realistic, and sensitivity tests revealed that the lowered surface latent and sensible heat fluxes from the Kami-koshiki Islands was the main factor in determining the distance between cloud streets. We had a very enjoyable dinner with Dr. Yoshizaki’s group. April 4 (9:35 am to 5:45 pm) In the morning on April 4, we talked to Dr. Yoshizaki again (9:35 to 10:00 am) regarding the X-BAIU experiment (the “X” resembles the pronunciation of ECS, the abbreviation of East China Sea) in Japan and the Green Island Mesoscale Experiment (GIMEX) to be held this May and June in Taiwan, and possible future collaboration on field experiments with similar scientific objectives between the two sides. Dr. Fumiaki Fujibe (藤部 文昭), senior researcher of the Second Lab of the Forecast Research Department at MRI, talked about his numerical study on the diurnal variation of low-level wind in the lee of a two-dimensional mountain, while his research interests are on heavy rainfall, local wind systems, and urban effects (10:00 to 10:45 am). While most of the work was preformed when Dr. Fujibe was in New Zealand, the study is closely related to my recent work on leeside mesolow and mesovortex of Taiwan. Dr. Isao Takano (高野 功) presented results of his numerical simulations of a mesoscale cloud system induced by topography and subsequent cyclogenesis off the south coast of Japan (10:45 to 11:30 am). He showed that under prevailing northwesterly flow, airflow was channeled into three stronger branches by the terrain of Chugoku Island. Airflow then converges at the leeside, forming convective clouds and a pair of cyclonic and anti-cyclonic vortices. With the aid of condensational heating, the cyclonic vortex than developed into a lee cyclone. Dr. Yoshizaki and his group members took us to a park inside the Agricultural and Fishery Research Institute (農業水產研究所), which is about 15 minutes from MRI by car. The park is perhaps the best place to view cherry blossom (sakura in Japanese) in Tsukuba City, and we had a very nice picnic under a large blooming cherry tree. During the spring, many tourists come from Taiwan to Japan to view the cherry blossom, and we also had the chance to enjoy the famous sights during our visit. Thanks to Dr. Yoshizaki and his colleagues. In the afternoon, we met with Dr. Tetsuo Nakazawa (中澤 哲夫) of the Second Lab of Typhoon Research Department (2:00 to 3:15 pm). He talked about his involvement in the field experiment to observe re-curving typhoon near Japan utilizing a total of 5 aerosondes, the strategy that they plan to use and evaluate for the typhoon ensemble forecast, as well as the current status of the funding available to support similar field campaigns in Japan. The experiment last season (summer of 2000) recorded a total of 58 hours of data in seven flight missions, while this year the experiment is scheduled to be held between 25 July and 18 August. After a short coffee break, we acquired the GEWEX Asian Monsoon Experiment (GAME) IOP reanalysis data version 1.1 from MRI, for the period from April to October of 1998, at resolution of 2.5, 1.25, and 0.5 latitude-longitude degrees. Dr. Mitsuru Ueno (上野 充) of the First Lab of Typhoon Forecast Department has interests on theoretical and modeling studies on tropical cyclones, and is currently working with the four remaining members in their lab on a five-year project to development the next-generation typhoon model, hopefully to be adopted by the JMA in 2006 (3:45 to 4:15 pm). The focuses of the model include 1) higher resolution with nested grid, 2) tropical cyclone initiation using bogusing and/or 4-D variational method, 3) cumulus parameterization, and 4) interaction between tropical cyclone and the underlying ocean. Mr. Akihiko Murata (村 田 昭彥) discussed effects of different cumulus parameterization schemes on the intensity forecast of Typhoon Flo occurred in 1990 (4:15 to 5:00 pm). Inside a convective rain-band, the melting of graupel and the collision-coalescence process contribute about equally to precipitable water, while a decrease in horizontal resolution to below 10 km does not necessarily increase the rainfall. Mr. Wataru Mashiko (5:00 to 5:45 pm) is working on the development of a two-way nested grid with movable mesh based on the MRI NHM, and he showed us his simulation of Typhoon Mirelle. We had dinner with Drs. Nakazawa and Zhu. April 5 (9:45 am to 12:15 pm) After talking to Dr. Yoshizaki again about the X-BAIU experiment, in particular their design of dual Doppler network (9:45 to 10:00 am), we met with Dr. Yoshinori Shoji (小司 禎教) of the Global Positioning System (GPS) group (10:00 to 10:45 am). Dr. Shoji introduced the GPS/MET Japan Dense Net Campaign 2000 in Tsukuba City to study the 2fine-scale distribution and evolution of precipitable water field. Over a 20 ， 20 km area in Tsukuba, a total of 75 antenna were installed to receive GPS signals, and the characteristics of data and preliminary results were presented. A similar field experiment has been planned for the summer of this year, from June 16 to September 9. Dr. Hiromu Seko (瀨古 弘) showed his study on the mechanism for maintenance and related problems of different types of mid-latitude meso-, scale line convection-precipitation systems (10:45 to 11:30 am). The types of line convection studied include the squall line type, the back-building type, and the back- and side-building type. The major conclusion was that the different types are largely determined by the vertical wind shear in the environment. We also met with Dr. Kenji Akaeda (赤板 健治) of the Doppler Radar Group and he talked about the ongoing plan to replace the conventional radars by Doppler radars in Japan. In Japan, all radars are operated by JMA, and five airport sites will have their radars upgraded to Doppler ones in the near future (11:30 am to 12:15 pm). Dr. Akaeda also guided us for a tour inside the radar room, and on top of the roof for their equipments. After a quick lunch with Dr. Yoshizaki, we took a bus from Tsukuba to Narita (成田) Airport, and then caught a flight to Nagoya to conclude our three-day visit to MRI. 3. Visit the Institute of Hydrospheric-Atmospheric Sciences, Nagoya University We arrived at Nagoya airport in the evening of April 5, where two colleagues of Dr. Tsuboki had been waiting for our arrival. After dinner we stayed at the Symposion of the Nagoya University (名古屋大學會館). The following is a description on our activities on April 6, when Professor Chen and myself visited the Institute of Hydrospheric-Atmospheric Sciences of the Nagoya University. April 6 (10:45 am to 12:15 pm) In the morning of April 6, at Nagoya University we met with the research group of Professors Hiroshi Uyeda and Kazuhisa Tsuboki (坪木 和久), whose focus is also in mesoscale meteorology. Because Professor Uyeda went to Shanghai, China while Dr. Tsuboki caught a severe cold in the previous day and was not able to meet us, we first talked to other colleagues and students in his group. The group has 15 members and is the largest in the institute, while some group members are Dr. Taro Shinoda (篠原 太郎, assistant professor), Dr. Sachie Kanada (金田 幸惠, post-doctoral research associate), Ph.D. student Mr. Qoosaku Moteki (茂木 耕作), and M.S. students Mr. Akira Kawabata (川火田 玲), Mr. Tetsuya Sano (佐野 哲也), Ms. Yukari Shusse, and Mr. Shingo Shimizu (清水 慎吾). Their research interests lie in all aspects of deep convections and precipitation systems, and their interactions with topography. Shortly after our lunch with the students, the colloquium started at 1:30 pm. Before our presentations, Dr. Tsuboki arrived at the institute although still not feeling well. We talked briefly about the current status of their research group as well as the source of funding for their research. In the colloquium, Professor Chen spoke first from 1:30 to 3:00 pm, and I spoke from 3:00 to about 4:15 pm on the same topics as at MRI. Our presentations again generated a great deal of discussion, which provides new insight for further research. Professor Tsuboki showed us their department (4:30 to 5:15 pm) and introduced the newly developed model called Cloud-Resolved Storm Simulator (CReSS). Still under development for new features, the CReSS model can be used to simulate a variety of mesoscale weather phenomena. After this, the students prepared bar-bi-que for dinner outside the institute, and we had a very good time. 4. Some Thoughts from the Visit This time Professor Tai-Jen Chen of the Department of Atmospheric Sciences and myself went visit the MRI and Nagoya University during the spring vacation, and met with many Japanese scientists, had a lot of interactions with them, and discussed the possibilities of more collaboration in both research and in field experiments in the future. In many aspects the atmospheric sciences in Japan are more advanced than even the western world, and those are certainly what we can learn from. For example, the mesoscale models developed at MRI and Nagoya University are capable of producing highly realistic results from simulations of a variety of mesoscale phenomena, including fine-scale ones. The fact that nearly all Japanese researchers and students employ numerical models in their research also clearly suggests that numerical simulation is the trend to do research today. It is also very valuable to travel overseas and discuss with, or present our research results to, foreign scientists because they may look at the same problem in different ways, and these new ideas will widen our view about issues at hand. The paper reprints that we collected during our visit, about 40 in total, also help us better understand the current research focus in mesoscale meteorology in Japan, and are valuable for our own work as well. In general, I think that Japanese people are hard workers, and their studies were carefully done with a lot of attention paid to even small details. Streets there are very clean, while people there are polite and well educated, and are enjoying their high quality of life. Of course not everything from Japan is necessarily good for us, but I think that we may also learn from our neighboring country about many other things besides atmospheric sciences.