Atmospheric Predictability

Abstract

The histories of numerical weather prediction and atmospheric predictability research are briefly reviewed in this article in celebration of the 125-year anniversary of the foundation of the Japan Meteorological Society. The development of numerical weather prediction in the 20th century has been intimately related to the progress of dynamic meteorology as stated in Section 1, including the development of the quasi-geostrophic system that is a basic tool to describe large-scale balanced flow approximately and the discovery of chaos that is the key concept of atmospheric predictability. In the 1990s, the rapid advancement of computer technology brought a regime shift in the predictability research from fundamental theoretical works with simple nonlinear dynamical systems (Section 2) to practical applied works with operational numerical weather prediction models (Section 3). Ensemble forecasts became in operations in major forecast centers at the end of the 20th century. Some current challenges in the atmospheric predictability research under THORPEX (THe Observing system Research and Predictability EXperiment) program are summarized in Section 4, such as targeted observations, new data-assimilation techniques, and interactive grand global ensemble forecasts.