Based on the National Basic Key Research Program (973)“Ocean-Atmosphere Interaction over the Joining Area of Asia and Indian-Pacific Ocean (AIPO) and Its Impact on the Short-term Climate Variation in China”, this paper introduces the definition of the “Joining Area of Asia and Indian-Pacific Ocean (AIPO)”; highlights the scientific significances for investigating the air-sea interactions in AIPO area from the view point of multi-level interactions in the climate system; and stresses why AIPO is a key area for the short-term climate variation and prediction in China.
    This program is also an important subject that meets the urgent needs of the national economy. Several key scientific issues are then emphasized. Finally the basic scientific objectives of this program are listed, which are: to reveal the characteristics of air-sea interaction in the AIPO joining area on seasonal to inter-annual time scales; to propose a theoretical framework about the impacts of these processes on the short-term climate variation in this area; and to provide theories and methods for improving the East Asian climate prediction on seasonal to inter-annual scales.