2013年梅雨监测及近50年江西梅雨气候特征

利用1959—2013年江西梅雨监测区37站降水量、气温资料和500 hPa西太平洋副热带高压脊线日平均位置资料,根据《梅雨监测业务规定》的相关指标,对2013年江西梅雨进行监测,并采用EOF等方法分析江西梅雨气候特征。结果表明:1)江西于2013年5月25日正式入梅,于6月29日结束,梅雨期总雨量为420.9 mm,梅雨强度为0.58。2)江西梅雨的时空变化特征是北部地区梅雨量的全区一致型分布占总方差的77.8%,将江西北部地区作为一个整体来分析其梅雨量的时空变化特征是合理的。3)江西气候平均入梅日为6月8日,出梅日为7月1日,梅雨季长度为23 d,梅雨量为352.7 mm,梅雨强度为-0.18。入梅日期、出梅日期、梅雨季长度和梅雨强度与梅雨量特征量之间存在显著的相关关系,入梅越早,出梅越晚,梅雨期长度越长,梅雨强度越强,梅雨量就越大。4)梅雨各特征量存在显著的年际和年代际变化特征,5个梅雨特征量具有相同的2—3 a周期变化,另外还主要存在6—8 a、13—15 a和21—23 a周期变化,但各参数在1959—2013年的不同时段具有不同的显著性。

Meiyu Monitoring Feature in 2013 and Climatological Characteristics of Meiyu in Jiangxi

According to the relevant indexes of ＂Meiyu monitoring service＂, the monitoring of Meiyu was executed in Jiangxi. The monitoring results show that in 2013 the onset date of Meiyu was l~ay 25, and the end date was June 29. By using the EOF method to study the temporal and spatial distribution of Meiyu, it found that Meiyu distribution of the same type accounts for 77.8% of the total variance. In addition, the 55-year Meiyu characteristic variable data of 37 stations were analyzed. According the climate average results, it shows that the onset date of Meiyu is June 8, the end date of Meiyu is July 1, the length of rainy season is 23 days, the rainfall and strength are 352.7 mm and 0.18, respectively. There are obvious correlations among these Meiyu characteristic variable data. The Meiyu precipitation is greater clue to its earlier onset, later end and longer duration. Also there is a prominent interannual and interdecadal variation of Meiyu characteristic variable data. According to the Morlet wavelet analysis method, the Meiyu characteristics present 2-3 year, 6-8 year, 13-15 year and 21-23 year periodic variations.