【作者】 吕军；

【导师】 江志红；

【作者基本信息】 南京信息工程大学 ， 气候系统与全球变化， 2012， 博士

【摘要】 本论文利用华东地区278站1961-2009年夏季逐日降水资料,同期美国NCEP/NCAR的逐日大气环流再分析资料和海温场资料以及国家气候中心提供的74项大气环流指数。采用环流合成分析、线性趋势分析、突变检验、小波分析、EOF和REOF等多种统计方法以及拉格朗日轨迹模式(HYSPLIT)等方法。揭示了淮北雨季相对于江淮梅雨和华北雨季独立存在的事实,制定了新的淮北雨季指标,综合分析了淮北雨季的时空演变特征以及影响淮北雨季的海洋大气环流特征以及水汽输送特征。主要结论如下：(1)通过对华东地区夏季各纬度降水的时空分布特征分析,揭示了淮北雨季是相对于江淮梅雨和华北雨季独立存在的雨季,在每年的6月后期,即江淮梅雨开始之后至华北雨季开始之前的这段时间里,在我国华东淮河以北的地区会有一个显著的连续降水时段发生,可以称之为淮北雨季,其范围大致为33°N-37°N,发生时段在6月后半段至7月大部分时期内。(2)利用500hPa副高脊线位置及逐日降水量对淮北雨季进行了划定,该定义使用要素相对较少,在实际分析过程中有利于起止日期的判断,并且适用区域更加广泛合理,能够区分出二段雨季,更加适用于天气和气候业务应用。(3)系统地分析了淮北雨季的气候特征,淮北雨季平均开始日为6月25日,平均结束日为7月16日,发生时期主要在6月后期和7月,平均降水量为182mm,具有比较明显的年代际变化特征,年际变化波动比较大。淮北雨季与江淮梅雨之间有一定的关系,江淮梅雨的开始对淮北雨季的监测和预报有一定的指示意义。(4)研究了淮北雨季平均及异常降水年水汽输送特征,发现影响淮北雨季降水的不同水汽通道的强度和变率各不相同,其中孟加拉湾、南海和东亚槽通道的影响相对显著。利用HYSPLIT4.9水汽轨迹模式,通过空气块追踪法对轨迹路径模拟分析可定量得出淮北雨季不同水汽源地区域的水汽贡献率,其中源自于印度洋的水汽输送对淮北雨季的贡献最大,其次是欧亚大陆和孟湾南海。(5)影响淮北雨季开始日早晚、降水量多少以及降水落区的因子主要有：南亚高压、副高、东亚槽、乌拉尔山阻高和鄂霍次克海阻高的位置和强度以及东亚夏季风的强弱等,通过研究这些因子的前期特征,确定淮北雨季主要的短期气候预测因子。此外,淮北雨季与太平洋海温以及ENSO事件等也有密切关系。更多还原

【Abstract】 In this paper, the data used are as follows:the summer daily rainfall data from 1961 to 2009 based on 278 meteorological observations in East China. The NCEP/NCAR daily means reanalysis data and SST data are applied in atmospheric circulation analysis. The 74 atmospheric circulation index offered from National Climate Center are also employed in this article. Common statistic functions such as circulation composite analysis, liner trend analysis, abrupt change testing, Wavelet analysis, SVD, EOF, REOF as well as HYSPLIT Model, etc. are applied in this article. A new definition for North Huaihe River Rainy Season(NHRS) is presented in this article. By synthetically analyzing the spatial-time distribution characteristics of NHRS and ocean-atmosphere circulation characteristics influencing NHRS, main conclusions are obtained as followings:1) The rainfalls in East China present clearly regional distributions characteristics. Compared comprehensively, in the later June every year, after the beginning of Jianghuai Meiyu(JHMY), and before the beginning the North China Rainy Season, a distinguishing continuous rainfall occurs in the northern areas of Huaihe Region in East China can be called as NHRS with its normal location from 33°N to 37°N, and its duration between later June and most July.2) The subtropical high ridge axis on 500hPa and daily precipitation are applied in defining the NHRS. The new definition refers less meteorological elements, and is profitably to estimate the beginning and ending dates in the practical operation. The new definition can be used on more extensive areas. Furthermore, two periods of NHRS can be easily classified by the new definition so as to be used to synoptic and climate practical operation.3) The average date of beginning day in NHRS is June 25th, and the ending day is July 16th. The mean precipitation of NHRS is 182mm, and shows obvious inter-annual and decadal variation. The spatial distribution of average precipitation presents more in the south than in the north, and the difference is obvious. Moreover, JHMY shows certain relationship with NHRS, characterized by the beginning of JHMY can monitor and forecast NHRS to some extent.4) As the strength and variation of various vapor passage are totally different, they play different role in precipitation of NHRS, among which the influence of vapors from the Bangladesh Bay, the South China Sea and the West Pacific are distinguishing. By analyzing the 264hr vapor passage grid of NHRS with HYSPLIT4.9 Model, different characters of the vapor transportation from the Bangladesh Bay, the South China Sea and Indian Ocean revealed the causations for the positive and negative years.5) The impact factors for NHRS includes:the location and strength of South Asian high; the location and strength of the blocking high, and trough exists in East Asia, the activity of East Asian Summer monsoon, etc. Besides, by studing the characteristics of impact factors above, one climatic forecasting model of the beginning date and precipitation for NHRS is established. Moreover, The Pacific SST and ENSO have close relationship with NHRS.更多还原