Past, Present and future of Typhoon Forecast

Toshiki Iwasaki (Tohoku Univ.)

I had been in charge of development of Numerical Weather Prediction (NWP) Model at Japan Meteorological Agency (JMA) from 1983 to 1998. In this talk, the history of NWP at JMA and its future perspective are briefly described with emphasis on typhoon forecast.

Typhoon is one of the most hazardous meteorological phenomena in Japan. JMA has made a great progress in NWP with the help of advancement of computational power, since the computer of IBM704 was installed in 1959. However, it took time to establish the operational typhoon track forecast based on NWP models, because the simulation of tropical cyclones has some difficulties compared with that of extratropical cyclones. We successfully started 2-day typhoon track forecast using a limited area model in 1988, and 3-day track forecast using a global model in 1996.

Rapid intensification, which sometime causes serious disasters, is very difficult to accurately simulate. Now, we are studying its mechanisms using high resolution cloud-resolving models. The rapid intensification is under strong influences of cloud microphysical processes. Furthermore, we have recognized a fundamental question which is more important for the rapid intensification, the Conditional Instability of Second Kind (CISK) or Wind Induced Sensible Heat Exchange (WISHE). Further studies are required to explore the air-sea interactions.