| 华北夏季降水异常的客观分区及时间变化特征 |
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| 引用本文： | 赵翠光,李泽椿.华北夏季降水异常的客观分区及时间变化特征[J].应用气象学报,2012,23(6):641-649. |
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| 作者姓名： | 赵翠光 李泽椿 |
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| 作者单位： | 1.南京信息工程大学，南京 210044 |
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| 基金项目： | 公益性行业（气象）科研专项（GYHY20110610），中国气象局气象关键技术集成与应用重点项目（GMAGJ2012Z08） |
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| 摘 要： | 应用1981—2007年华北地区703个站逐日加密站降水资料，运用旋转经验正交函数分解方法，对华北地区夏季降水进行了客观分区研究，并在此基础上应用Mann-Kendall和统计t检验方法分析了华北夏季降水不同区域的时间变化特征。结果表明:华北地区夏季降水区域性较强，华北地区夏季降水可分为7个典型天气区，7个典型天气区集中降水的起止时间不同，各分区的降水季节有别于自然季节，其中华北中部汛期开始迟，南、北部汛期开始早；华北东南部汛期结束最早，京津、河北东北部结束最晚。所分区域和所确定的各区域降水集中时间可应用到建立客观降水预报区域模型中，改善实际业务中客观降水的预报效果。
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| 关 键 词： | 华北地区 夏季降水量 客观分区 时间变化 |
| 收稿时间： | 2012-04-13 |
The Regionalization and Temporal Characteristic of Rainfall Anomalies in North China During Summer |
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| Zhao Cuiguang and Li Zechun.The Regionalization and Temporal Characteristic of Rainfall Anomalies in North China During Summer[J].Quarterly Journal of Applied Meteorology,2012,23(6):641-649. |
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| Authors: | Zhao Cuiguang and Li Zechun |
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| Affiliation: | 1.Nanjing University of Information Science and Technology, Nanjing 2100442.National Meteorological Center, Beijing 100081 |
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| Abstract: | North China is one of the three rainfall areas in eastern China. Precipitation over North China shows the characteristics of burstiness and locality. According to the statistics, 80%—90% precipitation occurs from June to August. Sometimes daily precipitation of a rainstorm can be up to 50% precipitation amount of that month. So it is important to forecast precipitation correctly especially to forecast larger magnitude precipitation correctly.Objective precipitation forecast is a difficult problem in NWP products interpretation at present in which models are always established station by station. Precipitation especially larger magnitude precipitation is small probability event for individual station, so establishing an effective forecast equation is difficult. Precipitation intensity, spatial and temporal distribution over North China has its own particularity. Due to the regionality characteristic, it is difficult to summarize in one weather mode. Objective partitioning can be used in establishment of precipitation forecast mode. Similar samples in the weather region are combined together. Regional forecast mode is more stable than single-station forecast mode, because the number of large-class precipitation samples is increased. In addition, sample data time selection is important for objective precipitation forecast modeling process.Based on the data of daily precipitation at 703 weather stations over North China from 1981 to 2007, which covers the domain of 32°—42°N, 110°—124°E, the temporal and spatial distribution characteristics are analyzed with Rotated Empirical Orthogonal Function (REOF) method. REOF analysis manifests that precipitation fields may be divided into 7 divisions. Mann-Kendall test and running t-test are used to analyze about the temporal change characteristics of different regions over North China during summer, in order to investigate the beginning and ending dates of rainy season specifically. The 7 divisions are different in precipitation beginning and ending dates. The initial date and final date of rainy season over North China are set up, and their dates are further identified, showing obvious regional features. Rainy season begins the earliest and ends the latest in the mountainous areas of the northeast of North China. It begins the latest in the central part of North China, and it ends the earliest in the southeast of North China. The concentration of precipitation time is different from the natural seasons. The long-term variation trend of precipitation anomalies in various regions and their stage are studied. |
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| Keywords: | North China precipitation during summer objective region time evolution |
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