江门市前汛期大暴雨的500hPa信号场分析  

AN ANALYSIS OF 500 HPA SIGNAL FIELD OF RAINSTORMS IN JIANGMEN DURING ANNUALLY FIRST FLOOD SEASON

作　　者：梁敏妍[1] 黄嘉佑[2] 徐碧裕 林国生 林卓宏 

机构地区：[1]江门市气象局,广东江门529030 [2]北京大学物理学院大气与海洋科学系,北京100871 [3]新会区气象局,广东江门529030

出　　处：《热带气象学报》2016年第3期425-432,共8页Journal of Tropical Meteorology

基　　金：广东省气象局课题;江门市气象局资金资助(2012C06)共同资助

摘　　要：使用广东省江门市1961-2010年的逐日降雨资料和NCEP再分析资料，对前汛期大暴雨过程的500hPa高度场进行信号场分析。研究结果表明：江门市前汛期的大暴雨500hPa信号场具有强信号和弱信号两种类型，强信号型出现频率为81％。在强信号类型中，根据信号场显著出现的地域分布可分为4种类型，第一类强信号中心在90～115°E，10—30°N区域；第二类在85～100°E，45—55°N区域；第三类在120—140°E，25～40°N区域；第四类在128～140°E，15～25°N区域。在综合信号场中，有“负-正-负”波列特征，表明在500hPa高度场中，由高纬引导南下东移的短波槽、北部湾低压和西南季风是形成江门地区大暴雨的主要天气形势。在信号场的异常面积和强度中，负异常表现突出，说明500hPa高度场的低值系统是形成大暴雨的主要系统。随着国内外数值预报产品对500hPa高度环流场的形势预报趋于成熟，在实际应用中可以应用数值模式提前预报信号场，从而对可能出现的大暴雨做出提前预报；此方法在研究中除了考虑单个样本的特征外，还综合对比气候长序列特征，从而可为更精准预测大暴雨提供科学决策依据。Using daily rainfall data and NCEP reanalysis data of Jiangmen during 1961-2010, we analyzed a signal field at the height Of 500 hPa in the torrential rain processes during the annually first flood season. The results are shown as follows. The season contains two types of 500 hPa signal field for rainstorms, which are respectively strong and weak. The frequency of strong signal is 81%. In the strong signal type, it can be subdivided into four types according to geographical distribution of a significant signal. The center of the first kind of strong signal was in the area of 90 to 115°E, 10 to 30 °N, the second category was in the area of 85 to 100 °E, 45 to 55 °N, the third kind was in the area of 120 to 140 °E, 25 to 40 °N and the fourth class was in the area of 128 to 140 °E, 15 to 25 °N. In＇the integrated signal field, it had ＂negative-positive-negative＂ wave charac- teristics, showing that in the 500 hPa height field, a shortwave trough guided southward from the high latitudes, a low pressure in the Beibu Gulf and the Southwest Monsoon are the main weather patterns for moderate to heavy storm weather in Jiangmen. In the anomaly area and intensity of the signal field, negative anomaly is dominant, suggesting low-value systems of the 500 hPa geopotential height field are mainly responsible for the rainstorms. With the numerical forecast products for prediction of 500 hPa height field circulation tending to be more and more reliable at home and abroad, the signal field could be predicted earlier in practical application of numeri- cal models, thereby making it possible to predict torrential rain in advance. The method introduced in this study considers not only the characteristics of a single sample but also makes comprehensive comparison of long climatological sequence characteristics, providing basis for scientific decision in predicting torrential rains more accurately.

关 键 词：天气学 前汛期 大暴雨 500hPa信号场 江门市 

分 类 号：P426.61[天文地球—大气科学及气象学]