Correspondence between the large volcanic eruptions and ENSO events over AD 1525–2000

ENSO is an interannual mode which may be affected by external forcing, such as volcanic eruptions. Based on the reconstructed volcanic eruptions chronology and ENSO sequences, both 195 large volcanic eruptions(VEI≥4) and 398 ENSO(El Ni?o and La Ni?a) events were extracted from 1525 to 2000. An analysis of the correspondence between the large volcanic eruptions and ENSO events was performed by matching the large volcanic eruptions with the types and magnitudes of ENSO events present in the 0–2 years after the eruptions. The results show the following:(1) The percentages of ENSO events within the 3 years after the large eruptions had increased to 68.3% from 31.7% compared with those with no-eruptions in the previous 0–2 years. In addition, the ratio of El Ni?o to La Ni?a events turned from 2:3 to 1:1, and more El Ni?o events occurred in the 0 year after eruptions in the low-latitudes of the Northern Hemisphere and in the tropics but more La Ni?a events occurred in the 0 year after in the high-latitudes of the Northern Hemisphere and the Southern Hemisphere.(2) After the eruptions, the weak(W) El Ni?o events had increased by 8 percentage points and the very strong(VS) El Ni?o events had decreased by 10 percentage points; conversely, there was a decrease by 15 percentage points of the weak La Ni?a events and an increase by 11.4 percentage points of the very strong La Ni?a events. Specifically, the percentages of strong La Ni?a events increased to a peak at 1(+1) year after the eruptions.(3) The percentage of eruptions followed by single-year ENSO was the greatest. The percentage of ENSO events that occurred in the consecutive 2 years following an eruption was approximately equal to the percentage of events that occurred consecutively 3 years following an eruption, and both sets of ENSO magnitudes showed a decreasing trend.     

黄土高原甘肃区降水变化与气候指数关系

基于黄土高原甘肃区34个气象站1961~2010年的逐日降水资料,结合线性趋势法、Mann-Kendall法和反距离加权插值等方法,对黄土高原甘肃区降水量时空变化进行分析,利用Morlet小波、交叉小波变换和小波相干谱分析其周期特征及其与太平洋年代际涛动（PDO）、厄尔尼诺/南方涛动（ENSO）指数相关关系。结果表明：研究区年降水量呈下降趋势,变化倾向率为-15.4 mm/10a,特别是20世纪90年代以来降水量下降趋势明显;就季节变化而言,降水量除冬季呈轻微增加外,其他各季均呈减少趋势,其中以秋季减少最为明显,其次为春、夏季。从空间分布来看,年降水量总体呈减少趋势,其东南地区降水量减少幅度高于西北部。研究区降水量存在2~3 a、4.3~5 a的年际振荡周期特征,呈现了同大尺度气候因子相似的变化特征;降水量与两大气候因子存在着多时间尺度的显著相关性,与PDO和ENSO存在5~5.6 a左右共振周期,位相谱月降水量变化位相比PDO和ENSO提前;低能量区降水量与PDO有3~3.5 a年的显著共振周期且接近同位相变化,与ENSO存在0~3 a和3~6 a呈负位相的共振周期。     

西南地区冬季气候异常的时空变化特征及其影响因子

利用1961-2010 年的多种观测资料,对西南地区冬季气候异常的时空演变特征及其影响因子进行了分析。结果表明：西南地区冬季气温变化主要存在全区一致和东、西部反位相两种模态,这两种模态均存在显著的年代际变化。全区温度的一致变化与东亚冬季风的异常有关,东、西反位相的变化与西太平洋副热带高压和冷空气的异常活动有关。冬季降水异常主要表现为全区一致的变化特征。北半球环状模(NAM,AO) 和ENSO对西南地区气温没有显著的影响。当NAM偏强(弱) 时,西南地区降水偏多(少)。El Niño 年,西南地区降水一致偏多;La Niña 年,西南地区中部降水偏多,东、西部降水偏少。2010 年冬季西南地区的干旱更有可能是由NAM异常引起的,而不是El Niño。     

黑河莺落峡站径流变化的影响因素分析

以黑河干流出山口径流控制站莺落峡水文站1960-2004年45年的径流序列为基础数据,采用相关分析、交叉谱分析、统计规律分析、降水—径流双累积曲线法等研究了全球变化、太阳黑子活动、ENSO循环和下垫面变化对黑河干流出山径流变化的影响。结果表明：①全球变化对莺落峡站径流变化影响较大;②莺落峡站年径流与太阳黑子相对数两序列在2年和3.3年两个振动周期上存在显著的相关关系,但在这两个存在显著相关关系的振动周期上太阳黑子相对数的周期波动变化都落后于莺落峡站年径流的周期波动变化;③ENSO循环对莺落峡站年径流变化有一定的影响,但是,El Nino事件和La Nina事件对莺落峡站年径流的影响时间持续较短,对事件发生当年的径流变化影响较大,对事件发生次年的径流变化影响较小;④流域下垫面变化对莺落峡站年径流量的变化影响较小。     

1960―2013 年华南沿海海洋站SST 变化及其影响因子

根据 1960―2013 年华南沿海 7 个海洋站的实测海表温度（SST）及全球平均表面温度、太平洋年代际涛动（PDO）、ENSO、南海高压、华南沿海近海面风速等资料,采用线性回归、Yamamoto 突变检验、小波分析、相关分析等方法,研究了近 54 a 华南沿海 SST 时空变化及其影响因子,结果表明：1）近 54 a 华南沿海的年平均 SST呈准同步变化和显著增暖趋势,其气候倾向率为 0.08~0.17℃/10 a,平均为 0.12℃/10 a,以冬季增暖最为显著;2）SST 变化在 1997/1998 年出现突变现象;3）SST 变化有多时空尺度的变化特征,其中最显著的变化周期是 2~4 a的年际变化;4）SST 变化深受 ENSO 事件的影响,约滞后于 MEI 指数 2~4 个月;5）影响 SST 变化趋势的主要因子有全球气候变暖、PDO、南海高压、华南沿海近海面层风速等。     

气候要素及El Niño/La Niña事件对中国陆地NPP变化的影响

植被净初级生产力（NPP）是表征陆地生态系统碳循环的重要指标,也是人类社会赖以生存与发展的物质基础。基于遥感—过程耦合模型（GLOPEM-CEVSA模型）模拟的中国区域NPP数据和气象站点观测资料以及厄尔尼诺/拉尼娜（El Ni?o/La Ni?a）事件信息,利用GIS空间分析技术和数理统计方法研究了中国植被NPP的时空格局、动态变化以及气候要素和El Ni?o/La Ni?a气候事件对其影响。结果表明,1982-2011年,中国植被NPP总体上以5.66 gCm^-2(10a)^-1的趋势增长,空间上,植被NPP在中国西部和东北北部、东部地区增加,而在东北中部、华北平原、内蒙中东部、长三角和珠三角地区减少。中国江淮地区植被NPP的降低与日照时数的减少具有较好的对应关系,在华北地区和新疆北部,NPP的增减取决于降水量的增减。东北地区日照时数的增加和气温的升高则是NPP增加的主要原因。就全国整体而言,在El Ni?o年植被NPP增加的区域略多于减少的区域,在La Ni?a年NPP增加的区域则与减少的区域基本相等,日照时数是造成El Ni?o年与La Ni?a年植被NPP差异的主要气候因子。未来需要更加关注辐射、极端气候事件以及人为空气污染对中国不同地区植被的影响。     

黄土高原北部丘陵沟壑区近160年土壤侵蚀量演变及其对ENSO事件的响应

对形成于1851~1861年的靖边（JB）聚湫内22.75 m沉积序列进行完整钻探,并基于XRF Core Scanning的元素分布划分旋回和年际冻融层,在高精度定年的基础上计算旋回及年际产沙量和产沙模数。结果表明：JB聚湫沉积序列由126个旋回叠加而成,且形成于1855~2014年的78 个年份中。JB聚湫内旋回产沙量和产沙模数变化范围分别为0.27×10 ⁴~22.44×10 ⁴t和0.09×10 ⁴~7.82×10 ⁴t/km ²;年际产沙量和产沙模数范围分别为0.27×10 ⁴~90.73×10 ⁴t/a和0.09×10 ⁴~23.40×10 ⁴t/(km ²·a)。 ENSO事件显著影响JB流域强降水作用下的侵蚀产沙,且在El Ni?o次年和La Ni?a年份发生侵蚀产沙的频率较高,可能是这些年份中东亚季风增强后带来更多强降水事件的结果。研究结果有效延长了黄土高原北部丘陵沟壑区小流域土壤侵蚀演变历史,充分理解ENSO事件驱动下该地区侵蚀产沙的响应,为黄土高原北部坝库建设、水土流失治理和防洪减灾等提供理论依据。     

黑河流域气象要素与全球性大气环流特征量的多尺度遥相关分析北大核心CSCD

黑河流域生态-水文过程集成研究是我国近年来干旱半干旱地区的研究热点,气候变化条件下流域生态-水文过程的响应机制是其中一个重要科学问题。基于1956-2015年黑河流域气温、湿度、降水观测数据及多个大气环流特征量监测资料,采用小波分析方法研究了流域气象要素与大气环流特征量的周期性及遥相关。结果表明:(1)流域气温与大气环流特征量的遥相关关系最为明显,湿度、降水次之。(2)气温与Ni?o3.4 SSTA、SOI的显著遥相关共同周期为12~16 a,与NAO、AO为9~11 a,与WP遥相关周期为5~9 a,与PDO为8~15 a。(3)湿度与NAO遥相关周期为4~5 a,与POL为3~6 a,与WP为9~15 a,与PNA为2~8 a。(4)降水与Ni?o3.4 SSTA遥相关周期为9~15 a,与NAO为2~4 a,与AO为3~7 a,与POL为11~19 a,与WP为9~14 a。(5)上述各遥相关周期的地域分布、显著时段与时滞特征各有差异。本文研究有助于加深流域气象要素对环流特征量响应机制的认识,为我国干旱半干旱地区内陆河流域严峻的水-生态问题的解决及水资源管理提供依据。     

1957—2011年中国中部不同气候带气候变化及其与ENSO的关系

依据湖北、河南与山西三省的气象资料,以湖北中部、河南中部、晋东南豫北和晋西北作为典型区域,研究1957—2011年中国中部亚热带湿润、温带半湿润、温带半干旱3个气候带气候变化特征及其与ENSO事件的关系。研究结果显示:研究区气候差异显著,自南向北降水集中程度增强、集中期明显缩短。湖北中部、河南中部降水年际波动大且无明显变化趋势,晋东南豫北地区、晋西北降水呈波动减少趋势。自20世纪80年代以来升温趋势显著,在90年代出现升温突变并呈持续上升趋势,且南北增温快,河南中部增温慢。暖事件(El Nio)具有使中部地区各气候带不同程度的降水减少和气温升高作用,冷事件(La Nia)则相反。暖事件使半干旱区和湿润区降水减少较多,使半湿润区减少幅度较小;冷事件使半湿润区的河南中部降水增加较多,使湿润区和半干旱区增幅较小。暖事件使半干旱区升温幅度最大,半湿润区的河南中部升温幅度最小;冷事件使气温下降幅度均较小,且不存在明显区域差异。     

西北太平洋海区年际至十年际海面变化尺度耦合与波动转型

利用多通道奇异谱分析(MSSA)等多尺度分析方法,对西北太平洋海区14个站位验潮序列的年际到十年际尺度海面波动的时空特征进行探讨.结果表明:2.5a周期和4.5a周期在振幅与相位上表现出与ENSO指数波动的尺度耦合,并存在显著的由低纬向高纬的振幅、能量递减的纬向传递特征.4.5a周期和8a周期与PDO变化同样表现出一定的尺度耦合波动,高纬各站位海面波动也表现出一定的自东向西的径向传递.在空间维上,PDO作用下的传播型波动的响应范围明显小于ENSO事件,反映了二者驱动机制的差异.该海区约在1973年和1998年左右发生过两次明显的海面波动转型,并与太平洋年代际涛动(PDO)存在一定关联.     

60年来黄河流域径流量时空变化(英文)

Water discharge data of the Yellow River over the past 60 years was analyzed using the continuous wavelet transform (CWT) and Mann-Kendall (MK) test methods to identify spatial and temporal variation patterns. Potential connections between water discharge in the Yellow River Basin and El Ni o/Southern Oscillation (ENSO) were also examined by the cross wavelet and wavelet coherence methods. CWT results show that the periodic oscillations in water discharges had occurred at the temporal scales of 1-, 2to 4-, 6to 8and 10to 22-year. It was also found that at the annual timescale (1-year) the phase relations between water discharge and ENSO were indistinct probably due to the strong influence by human disturbances. However, over the longer time scales, the phase relation becomes much clearer with an anti-phase relation being found mainly at inter-annual scale (2to 8-year) and in-phase relation at decadal scale (16to 22-year). According to the MK test results water discharge at most stations except Tangnaihai have decreased significantly and the abrupt change occurred in the mid-1980s or the early 1990s. The changes in water discharge were found to be influenced by both climate changes and human activities. Before 1970 the change in water discharge was positively related to precipitation variations in the river basin, but after 1970 the decrease in water discharge has been largely caused by various human activities including constructions of reservoirs, water abstraction and water-soil conservation with water abstraction being the main cause.     

我国汛期降水与ENSO不同位相的联系

利用本世纪以来较长年代的降水资源，分析了ＥＮＳＯ与我国各地汛期降水间的联系。结果表，不仅ＥＮＳＯ暖位相与冷位相我国汛期降水距平百分率的分布存在明显差异，而且ＥｌＮｉｎｏ年与其次年、ＬａＮｉｎｏ年与其次年降水距平面分率的分布均存在显差异。     

ENSO对韶关市1951~2013年降雨侵蚀力影响研究

选取1951~2013年韶关市分月降雨量数据,采用月降雨侵蚀力模型计算降雨侵蚀力,分析ENSO（厄尔尼诺-南方涛动）对韶关市降雨侵蚀力的影响。研究表明：① 韶关市降雨侵蚀力年际变化和年内变化较大,总体呈现波动上升趋势;② 降雨侵蚀力与赤道太平洋SST距平值呈现极显著相关,降雨侵蚀力随SST距平值增加呈现先增加后递减的趋势。ENSO冷暖事件发生时降雨侵蚀力较小,在其它土壤侵蚀因素不变的条件下,此时期的土壤侵蚀相对较轻;③ 降雨侵蚀力与SOI存在显著相关,降雨侵蚀力随着SOI增加而减小;④ 降雨侵蚀力与MEI呈现极显著的正相关关系。     

The influence of ENSO and PDO on tropical Andean glaciers and their impact on the hydrology of the Amazon Basin

Recent decades, particularly since the late 1970s, have witnessed a rapid retreat of glaciers in the tropical Andes. We compiled the changes in glacier surfaces along the eastern cordilleras of the tropical Andes of Peru and Bolivia since the early 1980s from the literature. Water levels from two Brazilian river basins in the Amazon basin (one (Madeira River) glacially fed by meltwater from the Andes and the other (Envira River) non‐glacially fed), were analysed for a 30‐year period between 1985?2014. Furthermore, precipitation data near these two basins were also analysed in order to understand the differential contributions of glacier melting and rainfall. Variations in the water levels from the glacially fed Madeira River showed that some years were associated with higher water levels even when the precipitation remained low during the corresponding season (May‐October). This observation was common when El Niño events occurred during the positive phase of Pacific Decadal Oscillation (PDO). Water levels in glacier‐fed Madeira River were slightly higher during the periods where El Niño and warm PDO co‐occurred. On the other hand, water levels in the Envira River were precipitation dependent; water levels were higher when the rainfall was high.     

Sediment and Water Discharge Assessment on Santiago and Pánuco Rivers (Central Mexico): The Importance of Topographic and Climatic Factors

This study explores the main factors controlling sediment and water discharge in the Santiago and Pánuco Rivers, the two largest rivers of central Mexico. Both Santiago and Pánuco Rivers are sourced in the Central Plateau of Mexico and flow in an opposite direction. Santiago River flows over a tectonically active margin draining to the Pacific Ocean, and Pánuco River flows into the passive margin of the Gulf of Mexico. Mean annual and monthly values of suspended sediment load and water discharge spanning around 50 years were used to evaluate sediment load and water discharge in these two rivers. Our findings indicated that Santiago River delivers to the ocean around 45% more sediment than Pánuco River. However, we found that Santiago River has about half the water discharge of Pánuco River. The high river gradient along Santiago River is likely to enhance the net erosion and sediment transport capacity. Water discharge at Pánuco Basin is higher than in Santiago Basin because the annual rainfall is higher for the former. The difference in sediment and water discharge for both rivers are also related to El Niño Southern Oscillation events. Our results indicated that water discharge in Santiago River increases during El Niño and La Niña events. In contrast, Pánuco River is mostly affected by La Niña events.     

Seasonal Response of Mean Monthly Streamflow to El Niño/Southern Oscillation in North Central Florida

The southeastern United States, including Florida, has been identified as a region of homogeneous response to the El Niño/Southern Oscillation (ENSO) climatic anomaly, in which mean monthly precipitation and discharge during winter is above or below normal following the onset of the warm (El Niño) or cold (La Niña) phase of ENSO, respectively. However, this understanding of the response is expanded through a study of the effects of the ENSO phenomenon on the probability distributions of mean monthly streamflows of the Santa Fe river. The Santa Fe river basin is situated between one region, which experiences the greatest proportion of annual streamflow during winter, and another where the largest percentage of annual flow occurs during late summer. The basin experiences both winter and summer peaks in precipitation and (subsequent) streamflow and may therefore display responses to ENSO during each season. A two-parameter lognormal distribution is employed to model these streamflows during warm and cold phases of ENSO. Increases in both the mean and the variance detected during warm phase winters are compatible with previous observations. Increases in variance apparent during cold phase summers have not been previously identified. These results, which have considerable bearing upon predictions of high and low flow probabilities during the year, suggest that the response in streamflow is not spatially homogeneous across the state.     

Aeolian Destabilization Along the Mojave River,Mojave Desert,California: Linkages Among Fluvial,Groundwater, and Aeolian Systems

It has been suggested by some that warm El Niño Southern Oscillation (ENSO) events have become stronger and more frequent as a result of global warming. This study aims to investigate whether there is any evidence for changes in the behavior of the ENSO phenomenon that may be attributed to global warming. Cluster analysis is carried out to group warm and cold events by various characteristics using the U.K. Climatic Research Unit air-temperature anomaly data set for the period 1856-1999. Analysis of the resulting groups of events and their relation to global temperature changes gives rise to various conclusions. First, the cold (La Niña) phase of the ENSO phenomenon has been more stable in the period of study than the warm (El Niño) one. Second, average strength warm events seem to be more frequent immediately preceding and during periods of steep global temperature rise, supporting the idea (Hunt, 1999) that more frequent El Niños are a short-term response in ocean-atmosphere coupling to rising global temperature.     

长江中下游流域旱涝急转事件特征分析及其与ENSO的关系（英文）

During recent decades,more frequent flood-drought alternations have been seen in China as a result of global climate change and intensive human activities,which have significant implications on water and food security.To better identify the characteristics of flood-drought alternations,we proposed a modified dry-wet abrupt alternation index(DWAAI)and applied the new method in the middle and lower reaches of the Yangtze River Basin(YRB-ML)to analyze the long-term spatio-temporal characteristics of dry-wet abrupt alternation(DWAA)events based on the daily precipitation observations at 75 rainfall stations in summer from 1960 to 2015.We found that the DWAA events have been spreading in the study area with higher frequency and intensity since 1960.In particular,the DWAA events mainly occurred in May and June in the northwest of the YRB-ML,including Hanjiang River Basin,the middle reaches of the YRB,north of Dongting Lake and northwest of Poyang Lake.In addition,we also analyzed the impact of El Ni?o Southern Oscillation(ENSO)on DWAA events in the YRB-ML.The results showed that around 41.04%of DWAA events occurred during the declining stages of La Ni?a or within the subsequent 8 months after La Ni?a,which implies that La Ni?a events could be predictive signals of DWAA events.Besides,significant negative correlations have been found between the modified DWAAI values of all the rainfall stations and the sea surface temperature anomalies in the Nino3.4 region within the 6 months prior to the DWAA events,particularly for the Poyang Lake watershed and the middle reaches of the YRB.This study has significant implications on the flood and drought control and water resources management in the YRB-ML under the challenge of future climate change.     

珠江流域多尺度极端降水时空特征及影响因子研究

基于珠江流域74个气象站点1952~2013年逐日降水和气温数据,采用POT抽样、Mann-Kendall（MK）趋势检验、泊松回归等方法,从降水量级、降水频率及发生时间等方面系统分析了珠江流域年、雨季及旱季3个时间尺度上的极端降水特征,并从降水对温度变化响应及ENSO影响等角度,探讨了极端降水变化特征的机理。研究表明：① 珠江流域极端降水年内分布不均,多发于4~9月,其中6月份发生频率最高;② 珠江流域极端降水频率在雨季及年际间分布较为均匀。但在旱季,珠三角地区极端降水在不同年份差异性较大;③ 在雨季及年际尺度上,极端降水年序列趋势性并不显著;而相对干旱季节,极端降雨量级、发生频次均随年份增加呈显著上升趋势,且发生时间提前。珠江流域农业以水稻(Oryzasativa)种植为主,旱季极端降水增加易导致冬汛及其引起的作物倒伏与农田渍涝等灾害,同时对秋冬防洪提出新的挑战,需要引起人们的关注;④ 温度升高和ENSO事件对珠江流域极端降水过程有显著影响。从ENSO影响的角度讲,在厄尔尼诺年,珠江流域西部极端降水量级和频率增加,而流域东部沿海区域极端降水量级减少,时间延后。     

Seasonal Response of Mean Monthly Streamflow to El Niño/Southern Oscillation in North Central Florida

The southeastern United States, including Florida, has been identified as a region of homogeneous response to the El Niño/Southern Oscillation (ENSO) climatic anomaly, in which mean monthly precipitation and discharge during winter is above or below normal following the onset of the warm (El Niño) or cold (La Niña) phase of ENSO, respectively. However, this understanding of the response is expanded through a study of the effects of the ENSO phenomenon on the probability distributions of mean monthly streamflows of the Santa Fe river. The Santa Fe river basin is situated between one region, which experiences the greatest proportion of annual streamflow during winter, and another where the largest percentage of annual flow occurs during late summer. The basin experiences both winter and summer peaks in precipitation and (subsequent) streamflow and may therefore display responses to ENSO during each season. A two-parameter lognormal distribution is employed to model these streamflows during warm and cold phases of ENSO. Increases in both the mean and the variance detected during warm phase winters are compatible with previous observations. Increases in variance apparent during cold phase summers have not been previously identified. These results, which have considerable bearing upon predictions of high and low flow probabilities during the year, suggest that the response in streamflow is not spatially homogeneous across the state.