Knowledge Resource Center for Ecological Environment in Arid Area
| 全球及区域陆地降水的多时间尺度变化特征及其与海温的联系 | |
| 其他题名 | Multi-timescale Variation Characteristics of Global and Regional Precipitation and Their Relationships with Sea Surface Temperatures |
| 徐保梁 | |
| 出版年 | 2016 |
| 学位类型 | 博士 |
| 导师 | 马柱国 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 已有研究表明，全球及区域尺度的降水发生了显著的变化，北非上个世纪发生的严重干旱、中国北方的干旱化及我国西北西部的暖湿化都是这些变化的具体表现。然而，现有研究在研究区域和时间尺度上相对单一，缺乏对区域间的比较和多时间尺度变化的整体认识。该论文采用近100年来的气候数据，利用时间尺度分离方法对降水时间序列进行尺度分离，提取不同时间尺度降水变化的特征信息，用分离后的多时间尺度降水序列研究全球和区域降水的多时间尺度特征，并在此基础上分析不同时间尺度降水变化与海温变化的关联性。最后，以我国东部南涝北旱的时空格局为典型个例，揭示太平洋海温的年代际变化对我国南涝北旱形成的调制作用。论文主要结论如下：（1） 系统地分析了全球陆地降水的多时间尺度特征。不论从全球陆地平均还是不同区域的降水上看，其年和季节降水均有较强的2~7年的年际变率，这很可能与ENSO2~7年的周期变化密切相关。但从长期趋势上看，1951–2010年全球年降水的变化趋势具有明显的区域性差异：半球尺度上，东半球以变干为主，西半球以变湿为主；大陆尺度上，非洲和欧亚大陆降水以减少趋势为主，其中非洲大陆最为剧烈，而北美、南美和澳洲大陆降水趋势均以增加为主。从年代尺度上看，1901–2010年间全球陆地平均年降水的变化以20年左右的年代际振荡为主，且区域性差异明显：欧亚大陆和北非降水的年代际振荡特征相似，但变化趋势相反；北美和南美降水均呈增加趋势，但北美在20世纪上半叶年代际振荡较强，下半叶振荡较弱，南美则相反；澳洲大陆降水的年代际振荡特征与南美接近，这与两者同处南半球有关。（2） 全球降水多时间尺度特征与不同时间尺度海温变化具有密切关系。降水与海温的关联性在不同的时间尺度下存在明显差异。在年际尺度上，全球陆地（南极除外）超过1/3地区的降水受热带海温异常影响；在年代际和多年代际时间尺度下，近乎全球的陆地（南极除外）降水均受到北太平洋与大西洋海温异常的影响。（3） 太平洋年代际振荡（Pacific Decadal Oscillation, PDO）和大西洋多年代际振荡（Atlantic Multi-decadal Oscillation, AMO）主导了全球典型干旱半干旱区降水的年代际变化。在空间结构上，全球陆地降水与El Ni?o和PDO的相关性近似，但均与AMO的相关性相反。全球陆地（南极除外）约3/4地区的降水对海温异常的响应敏感，但在不同的地区主导其降水变化的海温信号存在差异：在我国华北和美国中西部地区，PDO是其降水年代际变化的主导因素；在北非，AMO和PDO对其降水年代际变化的贡献相当；在澳大利亚东部和南美洲北部，El Ni?o对其降水变化的影响为主。（4） PDO对中国东部降水年代际旱涝格局的月分布具有调制作用。中国东部年降水的南北偶极子型在时间上不同步，这与PDO对月降水异常的调制作用有关，其在不同的月份呈现出不同的经向分布特征。当PDO处于冷（暖）位相时，1–4月降水异常结构与年降水类似，呈现“南旱北涝”（“南涝北旱”）型分布，但是其旱涝的位置明显偏南，且从1月到4月南北旱涝的分界线逐渐南移；而5–6月降水异常结构与年降水相反，呈现出“南涝北旱”（“南旱北涝”）的结构，且从5月到6月南北旱涝的分界线由33°N（淮河流域）南移至27°N附近；7–8月降水异常与年降水类似，呈现“南旱北涝”（“南涝北旱”）的结构，旱涝的中心位置分别位于长江中下游流域与华北；9–12月降水异常整体以偏多（少）为主，其中9–11月淮河流域降水为弱的负（正）异常，呈现出“＋－＋”（“－＋－”）的“三极子”型。此外，PDO对中国南方和华北地区年降水的贡献率不同，分别为7.6%和1.9%；而对于月降水，PDO对华北降水的贡献率在3.1%（7月）~18.6%（4月）间浮动，对南方地区降水的贡献率在2.3%（5月）~11.2%（12月）间浮动。 关键词：陆地降水，多时间尺度，海温变化，区域差异 |
| 英文摘要 | The global and regional land precipitation have changed significantly according to previous studies. The severe drought occurred over North Africa during the last century, the acidification over North China and the warm and wet tendency over the western part of Northwest China are all the evidences. However, the previous researches are focus on a relatively single areas and timescale, with no comprehensive knowledgement concerning the comparisons between regions and the changes on different timescales. In this thesis, precipitation data over the recent 100 years are used, and the advanced mode decomposition method is applied to separate the signals of time series and to extract information of precipitation changes on different timescales. After that, the multi-timescales characteristics of global and regional precipitation are studied. Based on those facts, the relationship between Sea Surface Temperatures (SSTs) and precipitation changes on different timescales are investigated. In the last part, a typical case, the “South flood North drought” dipole over eastern China, is studied to reveal the modulation of Pacific Decadal Oscillation (PDO) on this precipitation anomaly pattern.The main conclusions of this thesis are as follows:(1) Systematically investigated the observational facts of multi-timescale characteristics of global precipitation. Whether from the global land average or different regions precipitation, the annual and seasonal precipitation have a strong 2~7 years inter-annual variability, which is likely to be closely related to the 2~7 years cycle of ENSO. But regarding the long-term trends, trends of global precipitation from 1951 to 2010 have obvious differences among different regions: on hemispheric scale, the eastern hemisphere is drying, and the western hemisphere is wetting; on the continental scale, African and Eurasian Continental experiences decreasing trends on precipitation of which the African continent is the severest one, North America, South America and Australia also show decreasing trend. From the point of view of decadal timescale, 20 years decadal oscillation take the most part of global land average annual precipitation changes between 1901–2010, and regional differences are significant: decadal oscillation characteristics in Eurasia and North Africa are similar, but the trends are contrary; precipitation in North and South America both show increasing trend, but the inter-decadal oscillation in North America is relatively stronger in the first half of 20th century, and more weaker in the second half and South America experience an opposite change; the Australian continent has similar decadal oscillation characteristics with the South American continent, which may due to they both locate in the Southern Hemisphere.(2) The close relationships between global precipitation and SSTs on different timescales. The relationships between precipitation and sea surface temperature vary on different time scales. At the inter-annual timescale, over more than 1 / 3 of the global land (except Antarctica), the precipitation are affected by SSTA; at the decadal and multi-decadal timescales, almost all the global land’s (Antarctic except) precipitation are influenced by SST anomalies over the North Pacific and the Atlantic Ocean. (3) The PDO and Atlantic Multi-decadal Oscillation (AMO) predominant the decadal change of precipitation over the typical arid and semi-arid areas. Regarding the spatial structure, similar correlation exists between global land precipitation and El Ni?o and PDO, but contrary to that with AMO. Precipitation over more than 3 / 4 of the Global land (except Antarctica) area response sensitively to SSTA signals, but the dominant sea surface temperature (SST) signals are region-dependent: in North China and the Midwest region of the United States, PDO is the dominant factor on the inter-decadal variability of precipitation; in North Africa, the AMO and PDO contribute the most on the inter-decadal variability of precipitation.; in eastern Australia and Northern South America, El Ni?o has a predominant influence on precipitation variations.(4) The modulation of PDO on monthly precipitation anomaly patterns at inter-decadal timescale over the eastern China. The North-South dipole over eastern China varies in months, which is related to the month-dependent modulation of PDO on precipitation anomalies and its different meridional distribution in different months. During the PDO’s cold (warm) phase, the spatial structure of precipitation anomalies on Jan-Apr are similar to the annual precipitation, showing a "South drought North floods”("South floods North drought ") dipole, but its position is relatively more southerly and the dividing line of the dipole gradually move southerly from Jan to Apr. For May and June precipitation, there are “South flood –North drought” (“South drought–North flood”) patterns, which are opposite to annual precipitation anomalies, and the division between positive and negative anomalies moves southward gradually from around 30°N in May to about 27°N in June; the monthly precipitation anomaly structure in Jul to Aug is similar to annual precipitation, showing "South drought North floods”("South floods North drought ") pattern, the center of the drought area locates in the middle and lower reaches of the Yangtze River Basin and North China; for Sep to Dec precipitation, there are more (less) precipitation in general, of which the Sep to Nov precipitation over Huaihe River basin show weak negative (positive) anomalies, presenting a "+ – +"("– + –") triple pattern. In addition, PDO contribution to South China and North China precipitation are different, which are 7.6% and 1.9% respectively; and for monthly precipitation, it fluctuates between 3.1% (July) to 18.6% (April) for North China, and 2.3% (May) to 11.2% (December) for South China. Key Words: Land precipitation, multi-timescale, Sea Surface Temperatures, regional differences |
| 中文关键词 | 陆地降水 ; 多时间尺度 ; 海温变化 ; 区域差异 |
| 英文关键词 | Land precipitation multi-timescale Sea Surface Temperatures regional differences |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 气象学 |
| 来源机构 | 中国科学院大气物理研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287642 |
| 推荐引用方式 GB/T 7714 | 徐保梁. 全球及区域陆地降水的多时间尺度变化特征及其与海温的联系[D]. 中国科学院大学,2016. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [徐保梁]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [徐保梁]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [徐保梁]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
