兰州大学机构库 >大气科学学院
华北雨季的年际和年代际气候特征及其影响因子研究
Alternative TitleInterannual and Interdecadal Variabilities in the Rainy Season Characteristics over North China and their Influence Factors
于晓澄
Thesis Advisor封国林
2019-05-15
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Degree Discipline气象学
Keyword华北雨季 年际特征 年代际特征 雨季开始早晚 雨季雨量 大气环流 海温
Abstract利用国家气候中心的1961~2017年华北雨季监测资料、美国国家环境预报中心/大气研究中心(NCEP/NCAR)的大气再分析资料、NOAA海温资料,以及国家气候中心130项气候指数等资料,从华北雨季开始时间和雨季雨量两个方面研究了华北雨季的年际和年代际气候特征,及其各自的影响因子。1961~2017年期间,华北雨季开始最早在7月6日,最晚在8月10日,平均日期是7月18日,华北雨季开始时间具有显著的年际变化,但雨季开始早晚的长期变化趋势不太明显。根据57a华北雨季开始时间数据,筛选出异常偏早年(12年)和异常偏晚年(8年),对偏早年和偏晚年不同高度层次的合成环流场进行研究,发现华北雨季开始早晚与西太平洋副热带高压(副高)、东亚副热带西风急流(高空急流)、东亚夏季风等环流系统的活动关系密切,当对流层高层急流建立偏早偏强,中层副高第二次北跳偏早,低层东亚夏季风北进提前时,华北雨季开始偏早,反之华北雨季开始偏晚。同时利用相关分析方法,研究发现华北雨季开始早晚与春、夏季热带印度洋、赤道中东太平洋海温关系显著且稳定,并进一步利用回归方法分析可能的影响机制,结果表明当Niño3.4指数和热带印度洋海温全区一致模态(IOBW)为正值时,贝加尔湖大陆高压偏强,副高偏强偏南,东亚夏季风偏弱,导致华北雨季开始偏晚;当两个海温指数为负值时,则华北雨季开始偏早。利用华北雨季监测资料和全国160台站降水月平均资料,研究了华北地区夏季降水、盛夏降水以及雨季降水三者的关系和气候特征。发现华北雨季雨量约占华北盛夏降水量的60%,雨季雨量存在4年的年际振荡周期,进一步通过滑动t检验方法寻找华北雨季雨量的年代际转折,发现在1996年华北雨季雨量存在一个减少的突变,前后相差约40 mm。在华北雨季雨量转变的同时,对应的与降水有关的影响因子也发生了变化。通过计算华北雨季雨量与国家气候中心130项气候指数的滑动相关系数发现:前冬海温变化对华北雨季雨量的影响十分微弱,其中较为显著的热带南大西洋海温与华北雨季雨量的关系,也在1975年后逐渐减弱到无法通过显著性检验;在春季,北半球极涡面积指数、NINO A区海温指数与华北雨季雨量的关系发生了年代际增强,副热带南印度洋偶极子指数与华北雨季雨量的关系在20世纪90年代后一直保持显著的负相关;在雨季持续的7、8月,NINO 3、NINO 3.4两个区域的海温一直与雨季雨量有显著的负相关关系,而NINO A区海温与华北雨季降水的关系发生了年代际增强。7、8月西太平洋副热带高压西伸脊点在1976年后,与华北雨季雨量的关系发生年代际增强,呈显著负相关,西太副高的面积与强度并不是影响华北雨季雨量的关键因子。使用SPSS软件建立春季北半球极涡面积指数、夏季西太副高西伸脊点指数、夏季NINO 3.4区海温指数、夏季NINO 3区海温指数、NINO A区海温指数与华北雨季雨量的回归模型,所建方程为Y(华北雨季雨量)=-490.709-28.763×1(NINO 3区海温指数)+9.363×2(春季北半球极涡面积指数)。
Other AbstractUsing the National Climate Center's monitoring data of the rainy season in North China from 1961 to 2017, atmospheric reanalysis data from the National Center for Environmental Prediction/Atmospheric Research (NCEP/NCAR), NOAA Sea Surface Temperature(SST) data, and 130 climate indices from the National Climate Center, the interannual and interdecadal variabilities in the rainy season characteristics over North China and the influence factors are analyzed from the onset date and the precipitation of the Rainy season in North China. During the period from 1961 to 2017, the rainy season in North China began as early as July 6th, and at the latest on August 10th, the average date is July 18th. The onset date of the Rainy season in North China (OSDRS_NC) has significant interannual variations, but the long-term trend of the OSDRS_NC is not obvious. According to the OSDRS_NC from 1961-2017, the abnormal early years (12 years) and abnormal late years (8 years) were screened, and the synthetic circulation fields of the low, middle and high layers in the early and late years were studied. It is found that the OSDRS_NC is closely related to the activities of the western Pacific subtropical high (WPSH), the East Asian subtropical westerly jet stream (EAWJS), and the East Asian summer monsoon (EASM). When the establishment of the EAWJS, the second northward jump of the WPSH and the northward movement of the EASM are earlier than normal, the OSDRS_NC is earlier than normal, and vice versa. At the same time, using relevant analysis methods, it is found that the relationship between the OSDRS_NC and the SST over the Tropical Indian Ocean and the equatorial central and eastern Pacific is significant and stable in the spring and summer. Furthermore, the regression mechanism is used to analyze the possible influence mechanism. The results show that when the Niño3.4 index and the Indian Ocean Basin-wide Warming (IOBW) display positive (negative) anomalies, the WPSH enhances (weakens) and shifts to the south, the Lake Baikal high enhances (weakens) and the EASM weakens (enhance). These anomalies lead to late (early) onset of the rainy season in North China.Based on the monitoring data of the rainy season in North China and the average monthly precipitation data of 160 stations in China, the relationship and the climate characteristics of the precipitation in summer, in rainy season and in July, August was compared. It is found that 60% of the precipitation in July and August in North China comes from precipitation in the rainy season. There is a four-year interannual oscillation period in the precipitation of rainy season. Further, the precipitation in the rainy season in North China was found a reduced mutation in 1996 with a difference of 40 mm by the sliding t-test method. At the same time as the precipitation change in the rainy season in North China, the corresponding impact factors related to precipitation have also changed. By calculating the sliding correlation coefficient between the precipitation in the rainy season in North China and the 130 climate indices from the National Climate Center, it is found that the influence of the previous winter sea surface temperature on the rainy season in North China is very weak, and the relationship between the tropical South Atlantic SST and the rainy season is also gradually weakened after 1975 to pass the significance test; In the spring, the relationship between the Northern Hemisphere Polar Vortex Area Index, the NINO A SSTA Index and the precipitation in North China Rainy Season has increased interdecadal, the relationship between the South Indian Ocean Dipole Index and the precipitation in North China Rainy Season has remained significantly negative correlated since the 1990s; In July and August, the sea surface temperature in NINO 3 and NINO 3.4 had a significant negative correlation with the rainy season rainfall, while the relationship between the NINO A SSTA Index had an interdecadal enhancement. In July and August, the Western Pacific Sub Tropical High Westward Ridge Point Index showed a significant negative correlation with the rainy season rainfall in North China after 1976. At the same time, the area and intensity of the West Pacific subtropical high are not the key factors affecting the rainy season in North China. Using SPSS software to establish the regression model of spring northern hemisphere polar vortex area index, summer West Pacific subtropical high west extension ridge point index, summer NINO3.4 sea temperature index, summer NINO3 sea temperature index, NINOA sea temperature index and North China rainy season rainfall. The equation is Y (North China rainy season rainfall) = -490.709-28.763 × 1 (NINO 3 area sea temperature index) +9.363 × 2 (spring northern hemisphere polar vortex area index).
Pages56
URL查看原文
Language中文
Document Type学位论文
Identifierhttp://ir.lzu.edu.cn/handle/262010/338325
Collection大气科学学院
Affiliation大气科学学院
First Author AffilicationCollege of Atmospheric Sciences
Recommended Citation
GB/T 7714
于晓澄. 华北雨季的年际和年代际气候特征及其影响因子研究[D]. 兰州. 兰州大学,2019.
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