大气低频振荡在延伸期预报中的应用进展
Advances in the Application of Atmospheric Low-Frequency Oscillation on Extended Range Forecast
中文摘要：
延伸期预报是当前的服务重点，又是预报技术难点。近年来，根据大气低频振荡的特征，我国延伸期预报的研究和应用取得了一定的成果。为此，介绍了大气低频振荡与延伸期预报的一些进展。主要内容包括：（1）大气低频振荡与延伸期预报的可行性分析；（2）大气低频环流场的延伸期预报；（3）大气低频振荡的延伸期降水趋势预报；（4）大气低频振荡的延伸期天气过程预报。最后阐述了未来大气低频振荡研究前景的展望，并提出了低频天气学和低频动力学问题。为了能从大气低频振荡角度研究延伸期降水过程预报问题，特别介绍了一种新的预报方法——低频天气图，及低频天气图的技术要点和技术方法。在低频天气图上，低频天气系统（低频气旋和低频反气旋）以及它们的活动特征可以被用来定性地确定低频偏南（暖空气）和低频偏北（冷空气）气流的汇合，引起降水过程。2008，2009和2010年夏季上海地区延伸期降水过程预报表明，强降水过程预报效果较好，且预报时效为15～45d，可以在延伸期业务预报中应用。
中文关键词：
大气低频振荡，低频天气图，延伸期预报，天气过程
KeyWords：
atmospheric low-frequency oscillation, low-frequency synoptic chart, extended range forecast, precipitation process
Abstract：
The extended range forecast is now a key point of meteorological service and is also a difficult point of predictable techniques. According to the characteristics of atmospheric low-frequency oscillation, some results are obtained on research appliance of extended range forecast in China. Therefore it is introduced to some research advances for extended range forecast. The main contents contain that (1) the analysis of feasibility on atmospheric low-frequency oscillation and extended range forecast, (2)the extended range forecast of the low-frequency circulation fields, (3) the precipitation trends forecast of extended range of atmospheric low-frequency oscillation and (4) the synoptic processes forecast of extended range of atmospheric low-frequency oscillation. Finally, the prospects in atmospheric low-frequency oscillation are expounded. In addition, the problems about low-frequency synoptic meteorology and low-frequency are also proposed. Especially, to study extended range forecast from the viewpoint of atmospheric low-frequency, a new approach using the forecasting method of low-frequency synoptic chart (LFSC) is introduced recently in this paper. The low-frequency synoptic systems (low-frequency cyclones and anti-cyclones ) on LFSC and their action characteristics can be used to determine qualitatively the confluence between the south and north air current (warm and cool air ), and cause precipitation processes. Using LFSC method, it shows that the forecast results are good in Shanghai areas from 2008 to 2010 and its forecast validity period is 15~45 days. So the LFSC method can be applied in extended range forecast.