【作者】 谢月玉；

【导师】 王式功；

【作者基本信息】 兰州大学 ， 气象学， 2007， 硕士

【摘要】 澳洲冷空气活动通过加强西南气流，继而影响西太平洋副热带高压(副高)系统。副高的准确预报对我国天气特别是汛期降水预报有决定性作用。因此分析澳洲冷空气活动对副高影响有重要的现实意义。本文采用1948年～2003年NCEP再分析的格点资料及1971年～2000年长江中下游降水资料，利用相，分析及谱分析等统计方法，分析了澳洲冷空气活动与滞后副高指数变动关系，同时也进一步分析了澳洲冷空气活动与长江中下游降水的遥相关，得出了一些有新意的研究结果，主要结论如下：(1) 1月份，澳洲大陆为热低压控制，副高东退入海，赤道附近有明显的从北向南的越赤道气流；7月份澳洲大陆处冷高压控制中，副高北抬西伸影响亚洲大陆，赤道附近有强的由南向北越赤道气流。(2)澳洲冷空气活动具有10～15天的相对长周期和7.5～8.6天的相对短周期。副高强度指数逐日变化值与副高脊线指数逐日变化值都具有7.5～8.6天的主周期，这正好与澳洲冷空气活动7.5～8.6天的短周期相对应。(3) 6月份，澳洲变温与滞后5天的脊线位置变化呈显著负相关，与滞后10天的强度指数呈显著正相关；7月份，澳洲变温与滞后8天的脊线指数变化及面积指数变化呈显著负相关，与滞后10天的强度指数变化及滞后11天的西伸脊点变化呈显著负相关；8月份，澳洲变温与滞后5天的面积指数变化呈显著负相关，与滞后10天的西伸脊点变化呈显著正相关。滞后的副高指数变化值与澳洲变温存在较好线性相关。(4)当澳洲有较强冷空气活动后，加强了越赤道气流，继而导致副高有明显的北抬过程，副高北抬过程滞后澳洲冷空气活动的时间约为一周。(5)澳洲变温与涝年长江中下游降水存在着7.7天的遥相关。在7.7天周期时澳洲变温与涝年长江中下游降水呈现同位相振荡，当澳洲有冷空气活动时经7.3天后影响长江中下游降水。影响过程为：澳洲有较强冷空气活动时，副高北移，长江中下游受副高控制，晴天少雨；澳洲较弱冷空气活动时，副高南退，长江中下游地区处于副高边缘控制，呈现多降水天气。更多还原

【Abstract】 Activities of Australian cold air affect the West Pacific Subtropical High(WPSH) through intensifying west-south airflow. The accuracy of WPSH forcasting is crucial to weather forecast of China, specially important to the rainfall predicting during flood seasons. Therefore, it is significant and practical to analyze the influences of the activity of Australian cold air on WPSH. The relationship between Australian cold air activities and change of lagging WPSH index is studied by using statistical methods of correlation and spectrum based on the re-analysis data of grid point of NCEP during 1948-2003 and the data of precipitation in the middle-lower reaches of Yangtze River. Meantime, remote correlation between Australian cold air activity and rainfall of the middle-lower reaches of Yangtze River is discussed. Some new research results have been obtained from this thesis. The main conclusions are summed up as follows:(1) In January, Australian mainland is under the control of warm and low pressure. WPSH moves back to sea. There is airflow obviously crossing the equator from north hemisphere to south hemisphere. In July, Australian mainland is controlled by cold high. Moving of WPSH towards north and west affects Asia mainland. There is strong crossing-equator airflow from south hemisphere to north hemisphere.(2) Australian cold air activities relatively have long periods of 10-15 days and short periods 7.5-8.6 days . There are primary periods of 7.5-8.6 days in both daily changes of WPSH intensity index and WPSH ridge line, which is coincident with the 7.5-8.6 days short periods of Australian cold air activities.(3) In June, there is a significantly negative correlation at lag=5 between the change of Australian temperature and WPSH ridge line, and positive correlation at lag=10 between change of Australian temperature and WPSH intensity index. In July, there is significantly negative correlation between the change of Australian temperature and 8-day lagging WPSH ridge to west, and 8-day lagging WPSH acreage index change, and 10-day lagging WPSH intensity index change, and 11-day lagging WPSH ridge to west change. In August, Australian temperature change has significantly negative correlation with the change of 5-day lagging WPSH acreage index, and positive correlation with the change of 10-day lagging WPSH ridge to west. The change of lagging WPSH index has linear correlation with Australian temperature.(4) When there is stronger cold air activities in Australian, crossing-equator airflow is intensifyed, which results in WPSH moving towards north consequently. Lagging time of WPSH moving northward to Australian cold air activities is about seven days.(5) There is a remote correlation of 7.7 days between the change of Australian temperature and rainfall of the middle-lower reaches of Yangtze River in waterlogging year and they have in-phase surging in the 7.7-day periods. Australian cold air activities affect rainfall of the middle-lower reaches of Yangtze River after spending 7.3 days . The affecting processes are: when Australian cold air activity is stronger, WPSH moves northward and the middle-lower reaches of Yangtze River is sunny and controlled by WPSH; when Australian cold air activity weakens, WPSH moves southward and the middle-lower reaches of Yangtze River locate on the edge of WPSH with rainy days.更多还原