兰州大学机构库 >大气科学学院
中国季节划分及其对夏季降水的预测研究
Alternative TitleStudy on the Seasonal Division of China and its Prediction of Summer Precipitation
王正
Thesis Advisor丑纪范 ; 封国林
2019-09-05
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Degree Discipline气候学
Keyword多要素大气状态相似法 季节划分 年代际变化 夏季降水预测
Abstract自然天气季节的划分研究对天气预报和气候预测,尤其对中长期天气预报和短期气候预测具有十分重要的意义。综合考虑多种气象要素开展季节更替的客观化识别和划分,是气候监测、诊断分析和预测领域的一个重要课题,相关研究的开展将有助于更好地理解季节转变在气候增暖背景下的新特征。多要素大气状态相似季节划分法是近年来新发展的一种客观化季节划分方法,已被广泛应用于气候变化研究、气候监测和短期气候预测等科研和业务之中。该方法的关键之处在于多要素的融合和典型场的选取,其中典型场是指多要素大气状态相似法中所选取的能代表冬季和夏季平均气候特征的大气状态距平场。本论文基于NCEP/NCAR再分析资料、GPCP再分析降水数据和中国台站逐月降水资料,在改进多要素大气状态相似季节划分法的基础上,运用多要素大气状态相似季节划分法和统计诊断等方法,探讨了中国地区季节转换特征,前冬季节来临时间与夏季降水的联系及降水预测的机制问题。论文创新之处在于将季节变化研究与短期气候预测联系在一起,并将季节变化的研究成果转化到短期气候预测研究中。主要的研究内容和结论如下:(1)多要素大气状态相似季节划分方法研究   典型场作为多要素大气状态相似季节划分法的划分基准,其准确度对季节划分的研究结果至关重要。本文首先以1998年和2013年华中地区为例进行了分析研究,发现基于单年大气状态计算典型场能有效地减弱气候变化及季节转变阶段对季节划分结果的误差影响。基于新典型场得到的季节划分结果能准确地反映区域大气状态和大气环流的季节变化情况。研究还发现,基于单年大气状态计算的典型场与基于多年平均大气状态计算的典型场之间存在年代际变化的差异,且在气候变化转折阶段的差异尤为显著。
(2)南海地区季节转换特征分析   将多要素大气状态相似季节划分方法推广应用于南海地区的季节转换研究。结果表明,南海地区850hPa季节划分结果与各气象要素组成的大气整体状态的季节变化时间较吻合,各气象要素均有明显的季节变化特征,且大气环流和地表向上长波辐射也均随季节的变化而发生明显转变,这进一步验证了多要素大气状态相似季节划分方法对副热带地区的季节划分也是有效的。在南海地区,季节转变时各气象要素呈现不同的变化特征,由冬季向夏季转变时是以热力要素的变化为主导,而由夏季向冬季转变时则以动力要素的变化为主导。南海地区850hPa夏冬两季开始和结束时间的空间分布也能较为准确地反映大气环流和大气状态的季节变化空间演变特征。南海地区夏季在南海西北最先开始,在南海东南开始最晚,在南海西北地区先结束,最后在南海西南地区结束;南海冬季最早在西南部开始并逐渐向东北扩展,结束时却从西部和南部向中部和东北部地区收缩。
(3)中国季节转换特征研究     从中国季节的年代际演变特征角度分析发现,不同季节的持续时间与其主要影响因子之间的关联呈现明显的经纬向差异,并存在显著的此消(持续时间缩短)彼长(持续时间增长)式的互补关系。春夏、秋冬和冷暖季季节长度之间存在互补关系,其中春夏季节长度互补关系最好,互补区域也很广泛,而秋冬季节长度互补区域主要集中在西部地区。冷暖季节长度互补分布虽广泛,但其互补关系整体偏弱。对比1980年前后两个阶段发现,各季节的持续时间均表现出东西差异的年代际变化特征,其中春夏季的年代际变化集中在北部和西部地区,而秋冬季节则集中在西部地区。进一步分析影响季节变化的关键因子发现,季节持续时间年代际变化的显著区域与其关键因子年代际变化的显著区域一致,均集中在中国的北部和西部地区。(4)前冬季节特征对夏季降水的预测研究     探讨了中国东部前冬季节来临早晚(即冬季开始时间)与夏季降水之间的关系,建立了二者的统计关系和物理概念模型,并据此对夏季降水情况进行预测。前冬起始时间与东亚冬季风强度、东亚夏季风强度均呈现弱的正相关关系,前冬起始时间偏早,冬季风偏弱,而前冬起始时间偏晚,冬季风强。前冬季节起始偏早的年份,我国次年夏季表现为“﹣﹢﹣”降水分布特征,主雨带位于淮河流域,即出现Ⅱ类雨型的降水特点;而前冬季节起始偏晚的年份,我国次年夏季降水总体表现出Ⅰ类(主雨带位于黄河流域及其以北地区)和Ⅲ类雨型(主雨带位于长江中下游及其以南地区)的特点。对2012~2018年的中国夏季降水进行了回报预测和检验,发现本文所建立的统计模型预测技巧较高,且预测结果稳定。本文的研究表明,季节划分结果不再仅是一个时间的节点,它可将气候变化研究与短期气候监测、气候诊断和气候预测联系在一起,是研究气候变化与气候预测的一个很好的切入点。
Other AbstractThe division of natural weather seasons is very important for weather forecast and climate prediction, especially for medium and long-term weather forecast and short-term climate prediction. It is an important topic in the field of climate monitoring, diagnosis, analysis and prediction to identify and classify the seasonal change by comprehensively considering various meteorological elements. The development of relevant research will help to better understand the new characteristics of seasonal change in the context of global warming. In recent years, the multi-element atmospheric condition similarity season division method is a newly developed objective season division method, which has been widely used in climate change research, climate monitoring, short-term climate prediction and other scientific research and business. The key of this method lies in the fusion of multi-element and the selection of typical field, which refers to the atmospheric condition anomaly field selected in the multi-element atmospheric condition similarity method that can represent the average climate characteristics in winter and summer. Based on NCEP / NCAR reanalysis data, GPCP reanalysis precipitation data and monthly precipitation data of China stations, on the basis of improving the multi-element atmospheric condition similarity season division method, using the multi-element atmospheric condition similarity season division method and statistical diagnosis methods, this paper discusses the characteristics of season transition in China, the relationship between the starting time of the pre-winter and summer precipitation, and the mechanism of precipitation prediction. The innovation of this paper is to link the research of seasonal change with short-term climate prediction, and to translate the research results of seasonal change into the research of short-term climate prediction.The main research contents and conclusions are as follows:    (1) Study on the seasonal division method of multi-element atmospheric condition similarity      The accuracy of typical field is very important to the research results of season division. In this paper, we first take 1998 and 2013 in Central China as an example, and find that the calculation of typical field based on single year atmospheric condition can effectively reduce the error effect of climate change and seasonal change stage on seasonal division results. The results of seasonal division based on the new typical field can accurately reflect the regional atmospheric condition and the seasonal variation of atmospheric circulation. It is also found that there are interdecadal differences between the typical fields based on the single-year atmospheric condition and the typical fields based on the multi-year average atmospheric condition, especially in the transition stage of climate change.                 (2) Study on the characteristics of seasonal change in the South China Sea       The seasonal division method of multi-element atmospheric condition similarity is extended to the study of seasonal transition in the South China Sea. The results show that the 850hPa seasonal division results in the South China Sea are in good agreement with the seasonal change time of the overall atmospheric condition composed of meteorological elements. All meteorological elements have obvious seasonal change characteristics, and the atmospheric circulation and the surface upwardly long wave radiation also change significantly with the seasonal change, which further verifies the effectiveness of multi-element atmospheric condition similarity method in the subtropical zone. In the South China Sea, each meteorological element presents different changing characteristics during the seasonal change. The change from winter to summer is dominated by the change of thermal elements, while the change from summer to winter is dominated by the change of dynamic elements. The spatial distribution of the beginning and ending time of 850hPa summer and winter in the South China Sea can also accurately reflect the spatial evolution characteristics of the seasonal changes of atmospheric circulation and atmospheric condition. Summer in the South China Sea began first in the northwest of the South China Sea and the latest in the southeast of the South China Sea; summer ended first in the northwest of the South China Sea and finally in the southwest of the South China Sea. Winter began in the southwest and gradually expanded to the northeast, and its ending time contracted from the West and south to the central and northeastern regions.                                                                  (3) Study on the characteristics of seasonal change in China    From the perspective of the interdecadal evolution characteristics of Chinese seasons, it is found that the relationship between the duration of different seasons and its main influencing factors is obviously different in longitude and latitude, and there is a significant complementary relationship between this elimination (shortened duration) and that of the long (increased duration). There is a complementary relationship among the length of seasons in spring- summer, autumn-winter, and cold-warm season. The complementary relationship between the length of spring and summer season is better, and the complementary regions are widespread. The complementary regions of the length of autumn and winter season are mainly concentrated in the western region. The complementary relationship of length in cold and warm seasons is widely distributed, but the whole complementary relationship is weak. Compared with the two stages before and after 1980, the interdecadal variation of seasonal duration shows the difference between East and west. The interdecadal variation in spring and summer is concentrated in the north and West regions, while that in autumn and winter is concentrated in the West regions. Further analysis of the key factors affecting the seasonal change shows that the significant regions of the interdecadal change of the seasonal duration are consistent with the significant regions of the interdecadal change of the key factors, which are concentrated in the northern and western regions of China.                                    (4) Study on the prediction of summer precipitation by the characteristics of the pre-winter    The relationship between the onset time of the pre-winter season (i.e. the beginning time of last winter) and the precipitation in summer in eastern China is discussed. The statistical relationship and physical conceptual model of the onset time and the precipitation are established, and the prediction results of the precipitation in summer are provided accordingly. There is a weak positive correlation between the onset time of pre-winter and the intensity of East Asian winter monsoon and East Asian summer monsoon. The onset time of pre-winter is earlier, the onset time of pre-winter is weaker, and the onset time of pre-winter is later, and the intensity of winter monsoon is stronger. In the early beginning of the pre-winter season, the precipitation distribution in summer of the following year in China is characterized by - + -. The main rain belt is located in the Huaihe River Basin, i.e. the precipitation characteristics of type II rain pattern appear. In the years of late onset of the pre-winter season, the characteristics of type I (the main rain belt is located in the Yellow River Basin and its North region) and type III (the main rain belt is located in the middle and lower reaches of the Yangtze River and its south region) are generally shown. The return forecast and test of summer precipitation in China from 2012 to 2018 are carried out. It is found that the statistical model established in this paper has high prediction skills and stable prediction results.  The research of this paper shows that the result of season division is not only a time node, but also a good starting point for the study of climate change and climate prediction.
Pages131
URL查看原文
Language中文
Document Type学位论文
Identifierhttp://ir.lzu.edu.cn/handle/262010/338275
Collection大气科学学院
Affiliation大气科学学院
Recommended Citation
GB/T 7714
王正. 中国季节划分及其对夏季降水的预测研究[D]. 兰州. 兰州大学,2019.
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