期刊文献+
共找到24篇文章
< 1 2 >
每页显示 20 50 100
江淮入梅的年际变化及其与北大西洋涛动和海温异常的联系 被引量:85
1
作者 徐海明 何金海 董敏 《气象学报》 CSCD 北大核心 2001年第6期694-706,共13页
文中首先采用简单相关和合成分析的方法研究了江淮入梅的年际变化与前期冬季环流和前期冬、春全球海温的关系。研究结果表明江淮入梅的早晚与前期冬季北半球大型环流存在显著的相关 :入梅早的年份 ,其前期冬季北大西洋涛动强 ,北半球只... 文中首先采用简单相关和合成分析的方法研究了江淮入梅的年际变化与前期冬季环流和前期冬、春全球海温的关系。研究结果表明江淮入梅的早晚与前期冬季北半球大型环流存在显著的相关 :入梅早的年份 ,其前期冬季北大西洋涛动强 ,北半球只有一个强的极涡并位于格陵兰上空 ,东亚大槽弱 ;入梅晚的年份 ,则其前期冬季环流表现为 ,北大西洋涛动弱 ,北半球存在两个极涡 ,其中一个仍然位于格陵兰上空 ,而另一个则位于西伯利亚上空 ,东亚大槽较常年强。江淮入梅的年际变化与前期冬春北大西洋海温的相关分析表明 :入梅早的年份 ,北大西洋海温较常年偏暖 ;入梅晚的年份 ,前期冬春北大西洋海温较常年偏冷。文中还用 CCM3模拟了冬、春季北大西洋海温增暖对后期江淮入梅和梅雨期降水的影响 。 展开更多
关键词 年际变化 北大洋涛动 海温异常 江淮流域 梅雨
下载PDF
Global Climate Internal Variability in a 2000-year Control Simulation with Community Earth System Model(CESM) 被引量:13
2
作者 WANG Zhiyuan LI Yao +1 位作者 LIU Bin LIU Jian 《Chinese Geographical Science》 SCIE CSCD 2015年第3期263-273,共11页
Using the low-resolution (T31, equivalent to 3.75°× 3.75°) version of the Community Earth System Model (CESM) from the National Center for Atmospheric Research (NCAR), a global climate simulation ... Using the low-resolution (T31, equivalent to 3.75°× 3.75°) version of the Community Earth System Model (CESM) from the National Center for Atmospheric Research (NCAR), a global climate simulation was carried out with fixed external forcing factors (1850 Common Era. (C.E.) conditions) for the past 2000 years. Based on the simulated results, spatio-temporal structures of surface air temperature, precipitation and internal variability, such as the E1 Nifio-Southem Oscillation (ENSO), the Atlantic Multi-decadal Oscilla- tion (AMO), the Pacific Decadal Oscillation (PDO), and the North Atlantic Oscillation (NAO), were compared with reanalysis datasets to evaluate the model performance. The results are as follows: 1) CESM showed a good performance in the long-term simulation and no significant climate drift over the past 2000 years; 2) climatological patterns of global and regional climate changes simulated by the CESM were reasonable compared with the reanalysis datasets; and 3) the CESM simulated internal natural variability of the climate system performs very well. The model not only reproduced the periodicity of ENSO, AMO and PDO events but also the 3-8 years vari- ability of the ENSO. The spatial distribution of the CESM-simulated NAO was also similar to the observed. However, because of weaker total irradiation and greenhouse gas concentration forcing in the simulation than the present, the model performances had some differences from the observations. Generally, the CESM showed a good performance in simulating the global climate and internal natu- ral variability of the climate system. This paves the way for other forced climate simulations for the past 2000 years by using the CESM. 展开更多
关键词 Community Earth System Model (CESM) climate simulation past 2000 years climate system intemal variability
下载PDF
Possible Impact of the Summer North Atlantic Oscillation on Extreme Hot Events in China 被引量:10
3
作者 SUN Jian-Qi 《Atmospheric and Oceanic Science Letters》 2012年第3期231-234,共4页
This paper reveals that the summer North Atlantic Oscillation (SNAO) is closely related to the extreme hot event (EHE) variability in China during the period of 1979 2009, with a positive-phase (negative-phase) SNAO c... This paper reveals that the summer North Atlantic Oscillation (SNAO) is closely related to the extreme hot event (EHE) variability in China during the period of 1979 2009, with a positive-phase (negative-phase) SNAO corresponding to less (more) EHEs in northern China. The summer circulation anomalies associated with the SNAO give further confirmation of the above relationship. In a positive-phase (negative-phase) SNAO year, there is an anomalous cyclone (anticyclone) over central East Asia, which can increase (decrease) the total cloud cover over this region. Such changes of the total cloud cover can then decrease (increase) the solar radiation reaching the surface, which is consequently unfavorable (favorable) to the formation of EHEs over northern China. 展开更多
关键词 summer North Atlantic Oscillation extreme hot events total cloud cover solar radiation
下载PDF
Downscaling and Disaggregating NAO-conflict Nexus in Pre-industrial Europe 被引量:5
4
作者 Harry Fung LEE ZHANG David Dian +1 位作者 PEI Qing FEI Jie 《Chinese Geographical Science》 SCIE CSCD 2016年第5期609-622,共14页
Recently, the desiccation effect of the North Atlantic Oscillation(NAO) is found to be positively correlated with violent conflict in pre-industrial Europe, with agricultural shrinkage and its subsequent economic shoc... Recently, the desiccation effect of the North Atlantic Oscillation(NAO) is found to be positively correlated with violent conflict in pre-industrial Europe, with agricultural shrinkage and its subsequent economic shocks to be their causal link. However, it remains unexplored whether the correlation persists if the study period is extended backward in time, a different definition of violent conflict is applied, or the relationship is examined at lower geographic levels. In this study, we based on 835 internal disturbance incidents in Europe during 1049–1800 to conduct long-temporal and multi-scalar examination on the NAO-conflict nexus. ′Time-series′ and ′panel data′ disaggregation approaches, together with Granger Causality, Multiple Regression, and Survival Analyses were applied to verify the nexus quantitatively. Results show that the positive NAO-conflict correlation was significant at the continent and physiographic zone levels. During the positive NAO phases, the annual probability of internal disturbance outbreak increased by 70.0% in the southern Europe and the Mediterranean, a zone most affected by the NAO-induced desiccation effect. Yet, the NAO-conflict correlation was rather inconsistent when it was downscaled to the sub-regional level. Moreover, the NAO-conflict correlation was inflated under the time-series approach, while the panel data approach demonstrated the region-specific nature of the NAO forcing more clearly. The associated implications in examining climate-conflict nexus are discussed. Our findings may be crucial in examining violent conflict in the northwestern Africa, a highly agricultural region affected by the NAO. 展开更多
关键词 climate change North Atlantic Oscillation (NAO) violent conflict internal disturbance EUROPE
下载PDF
Impacts of Climatic Change on River Runoff in Northern Xinjiang of China over Last Fifty Years 被引量:6
5
作者 YANG Yuhui CHEN Yaning +2 位作者 LI Weihong WANG Minzhong SUN Guili 《Chinese Geographical Science》 SCIE CSCD 2010年第3期193-201,共9页
The characteristics of climatic change and fiver runoff, as well as the response of fiver runoff to climatic change in the northern Xinjiang are analyzed on the basis of the hydrological and meteorological data over t... The characteristics of climatic change and fiver runoff, as well as the response of fiver runoff to climatic change in the northern Xinjiang are analyzed on the basis of the hydrological and meteorological data over the last 50 years by the methods of Mann-Kendall nonparametric test and the nonlinear regression model. The results show that: 1) The temperature and the precipitation increased significantly in the whole northern Xinjiang, but the precipitation displayed no obvious change, or even a decreasing trend in the northern mountainous area of the northern Xinjiang. 2) River runoff varied in different regions in the northern Xinjiang. It significantly increased in the northern slope of the Tianshan Mountains and the north of the northern Xinjiang (p = 0.05), while slightly ificreased in the west of the northern Xinjiang. 3) North Atlantic Oscillation (NAO) affects fiver runoff by influencing temperature and precipitation. The NAO and precipitation had apparent significant correlations with the fiver runoff, but the temperature did not in the northern Xinjiang. Since the mid-1990s fiver runoff increase was mainly caused by the increasing temperature in the northern slope of the Tianshan Mountains and the north of the northern Xinjiang. Increased precipitation resulted in increased fiver runoff in the west of the northern Xinjiang. 展开更多
关键词 climatic change river runoff Mann-Kendall test nonlinear regression model NAO northern Xinjiang
下载PDF
Impact of Preceding Summer North Atlantic Oscillation on Early Autumn Precipitation over Central China 被引量:3
6
作者 XU Han-Lie FENG Juan SUN Cheng 《Atmospheric and Oceanic Science Letters》 CSCD 2013年第6期417-422,共6页
This study examined the impact of the preceding boreal summer(June–August) North Atlantic Oscillation(NAO) on early autumn(September) rainfall over Central China(RCC). The results show that a significant positive cor... This study examined the impact of the preceding boreal summer(June–August) North Atlantic Oscillation(NAO) on early autumn(September) rainfall over Central China(RCC). The results show that a significant positive correlation exists between the preceding summer NAO and the early autumn RCC on the interannual timescale. In order to understand the physical mechanism between them, the role of ocean was investigated. It was found that the strong summer NAO can induce a tripole sea surface temperature anomaly(SSTA) in the North Atlantic; this SSTA pattern can persist until early autumn. The diagnostic analysis showed that the tripole SSTA pattern excites a downstream Atlantic-Eurasian(AEA) teleconnection, which contributes to an increase in RCC. The circulation anomalies related to SSTA caused by the weak NAO are opposite, so the RCC is less than normal. The results imply that the preceding summer NAO may be regarded as a forecast factor for the early autumn RCC. 展开更多
关键词 North Atlantic Oscillation early autumn rainfall tripole sea surface temperature anomaly Atlantic-Eurasian teleconnection atmospheric-oceanic coupled bridge
下载PDF
Weakening of Winter North Atlantic Oscillation Signal in Spring Precipitation over Southern China 被引量:3
7
作者 ZHOU Bo-Tao 《Atmospheric and Oceanic Science Letters》 CSCD 2013年第5期248-252,共5页
In this study,the relationship between the North Atlantic Oscillation (NAO) in winter (DecemberFebruary) and the precipitation over southem China (SCP) in the following spring (March-May) was investigated.Resu... In this study,the relationship between the North Atlantic Oscillation (NAO) in winter (DecemberFebruary) and the precipitation over southem China (SCP) in the following spring (March-May) was investigated.Results showed an interdecadal change,from strong to weak connection,in their connection.Before the early 1980s,they were highly correlated,with a strong (weak) winter NAO followed by an increased (decreased) spring SCP.However,after the early 1980s,their relationship was weakened significantly.This unstable relationship may be linked to the climatological change of East Asian jet.Before the early 1980s,the wave train along the Asian jet propagated the NAO signal eastward to East Asia and affected local upper-tropospheric atmospheric circulation.A strong NAO in winter led to an anomalous anticyclonic circulation at the south side of 30°N in East Asia in spring,resulting in an increase of SCP.In contrast,after the early 1980s,the wave train pattern along the Asian jet extended eastward due to strengthening of the climatological East Asian jet.Correspondingly,the NAO-related East Asian atmospheric circulations in the upper troposphere shifted eastward,thereby weakening the linkage between the spring SCP and the winter NAO. 展开更多
关键词 North Atlantic Oscillation precipitation over southern China interdecadal change
下载PDF
Relationships between the Oxygen Isotopes in East Asian Stalagmites and Large-Scale Atmospheric and Oceanic Modes 被引量:2
8
作者 JING Yuan-Yuan LI Shuanglin +1 位作者 WAN Jiang-Hua LUO Fei-Fei 《Atmospheric and Oceanic Science Letters》 CSCD 2014年第6期540-545,共6页
The stalagmite δ18O record is known to be associated with the climate, but the specifics of the relationship remain unclear. It may not represent variation in air temperature or precipitation, but instead reflect int... The stalagmite δ18O record is known to be associated with the climate, but the specifics of the relationship remain unclear. It may not represent variation in air temperature or precipitation, but instead reflect integral changes of monsoon circulation, especially water vapor sources(the so-called "circulation effect"). Since large-scale atmospheric-oceanic modes such as the Atlantic Multidecadal Oscillation(AMO), Pacific Decadal Oscillation(PDO), and North Atlantic Oscillation(NAO) exert significant effects on Asian monsoon, in this paper the authors investigate the relationships of the East Asian stalagmite δ18O record with these modes. The last three centuries form the focus of our study, for which the authors use reconstructed as well as instrumental data. Considering the impacts of human activity, our analysis is conducted with respect to two periods—the pre- and post-industrial periods. The results show significant lead-lag connections: a positive correlation peaks when the PDO leads East Asian stalagmite δ18O by 3 years, which is persistent over the past 300 years; while the relationships of the AMO and NAO with the East Asian stalagmite δ18O record show significant differences in the post-industrial relative to the pre-industrial period. This implies that the East Asian stalagmite δ18O record may primarily reflect the PDO signal. 展开更多
关键词 STALAGMITE oxygen isotope large-scale circulation lead-lag correlation East Asian climate
下载PDF
Two Opposite Extreme Events in Seasonal Mean Winter Rainfall over East China during the Past Three Decades 被引量:2
9
作者 GUAN Zhao-Yong JIN Da-Chao 《Atmospheric and Oceanic Science Letters》 CSCD 2013年第5期240-247,共8页
In this study,the extremes of winter seasonal mean precipitation have been investigated by using daily precipitation data from 91 stations in East China,the National Centers for Environmental Prediction/the National C... In this study,the extremes of winter seasonal mean precipitation have been investigated by using daily precipitation data from 91 stations in East China,the National Centers for Environmental Prediction/the National Center for Atmospheric Research (NCEP/NCAR) monthly reanalysis,and sea surface temperature data from the Hadley Centre for 1979-2007.The largest anomalous rainfall amount was observed in regions south of the Yangtze River.In the most recent three decades,extreme events in the seasonal mean winter precipitation occurred in 1985 and 1997.Because it was influenced mainly by a La Ni(n)a event,the precipitation in 1985 showed a deficit following a stronger winter monsoon.The rainfall amount in 1997 was influenced by E1 Ni(n)o and was significantly larger than normal with a weaker winter monsoon.Both the circulation anomalies and wave energy dispersions during the winters of 1985 and 1997 differed significantly.In 1985,the North Atlantic Oscillation anomalously excited the Eurasian-Pacific teleconnection and circumglobal teleconnection phenomena.Consequently,Rossby wave energy propagated along the north and south branches of the westerlies,strengthening the East Asian trough along with a stronger winter monsoon,which facilitated the wintertime dry extreme in East China.In 1997,however,Rossby wave energy propagated from low latitudes northeastward into the southern part of China,resulting in a weaker winter monsoon and the wettest winter.The results of this study will be helpful for future monitoring and prediction of extreme winter rainfall events in East China. 展开更多
关键词 extreme seasonal mean rainfall winter monsoon ENSO event Rossby waves East China
下载PDF
Intensity of the Trough over the Bay of Bengal and Its Impact on the Southern China Precipitation in Winter 被引量:2
10
作者 ZONG Hai-Feng BUEH Cholaw +1 位作者 WEI Jie CHEN Lie-Ting 《Atmospheric and Oceanic Science Letters》 2012年第3期246-251,共6页
In this study, the intensity of the trough over the Bay of Bengal (BBT) and its association with the southern China precipitation, the Madden-Julian Oscillation (MJO) and the Rossby wave propagation along the African-... In this study, the intensity of the trough over the Bay of Bengal (BBT) and its association with the southern China precipitation, the Madden-Julian Oscillation (MJO) and the Rossby wave propagation along the African-Asian subtropical Jet stream (AASJ) are investigated on the intraseasonal time scale. The results show that the intensity of the BBT affects the southern China precipitation more directly and to a greater degree than the MJO. The peak amplitude of the BBT tended to occur in phase-3 of the MJO. The strong BBT was substantially modulated by the Rossby wave propagation along the AASJ, which was triggered by the anomalous upstream circulation similar to the pattern of the North Atlantic Oscillation (NAO). Therefore, from the perspective of medium- and extended-range weather forecasts, the NAO- like pattern may be regarded as a precursory signal for the strong BBT and thus the southern China precipitation. 展开更多
关键词 the trough over the Bay of Bengal MJO PRECIPITATION NAO Rossby wave
下载PDF
Spatial and Temporal Variability of Water Vapor Content during 1961-2011 in Tianshan Mountains,China 被引量:2
11
作者 HU Wen-feng YAO Jun-qiang +1 位作者 HE Qing YANG Qing 《Journal of Mountain Science》 SCIE CSCD 2015年第3期571-581,共11页
Based on the climate factors data and surface vapor pressure (SVP) data of 44 weather stations in Tianshan Mountains during the years 1961-2011, this paper establishes a water vapor content (WVC) estimation model ... Based on the climate factors data and surface vapor pressure (SVP) data of 44 weather stations in Tianshan Mountains during the years 1961-2011, this paper establishes a water vapor content (WVC) estimation model according to the relationship between monthly WVC of radiosonde and corresponding SVP and analyzes the spatial and temporal variability of WVC and their causes. The results show that the WVC is linearly and negatively related to the elevation and longitude (Vertical zonality and Longitude zonality), while it was not linearly related to the latitude. The westerly wind, geographical situation and sea level elevation composed complex surface conditions to influence the spatial distribution of WVC in the Tianshan Mountains. The Mann-Kendall (M-K) statistical test shows a significant increasing trend in the mean annual WVC in Tianshan Mountains during 1961- 2011(P 〈 0.001), with a rate of 0.23 mm/decade, and indicates an abrupt turning point in 1985 (P.〈0.001). Correlation analysis shows that the WVC are significantly correlated to the temperature, especially during the winter, but the summer WVC are significantly correlated to the precipitation. In addition, the North Atlantic Oscillation Index (NAOI) and the Arctic Oscillation Index (AOI) are significantly correlated to the winter WVC in the Tianshan Mountains. As a new Microwave radiometric profilers (MWRPs) instrument, the MP- 3000A provides continuous, real-time and high temporal resolution atmospheric profiles up to 10 km. In order to monitor water vapor and atmosphere profiles in Tianshan Mountains, an MP-3000A was established in Urumqi (43.8°N, 87.58°N) in May 2008. The results indicated that the MP-3oooA was applicable to this area, and the evolutionary process of water vapor and the WVC peak values of MP- 3000A were a strong signal for rainstorm and flood forecasts for Urumqi and the Tianshan Mountains. 展开更多
关键词 Water vapor content Spatial variability Temporal variability Microwave radiometers Tianshan Mountains
下载PDF
Greenland Ice Sheet Elevation Change in Winter and Influence of Atmospheric Teleconnections in the Northern Hemisphere 被引量:1
12
作者 CHEN Lin-Ling Ola M. JOHANNESSEN +1 位作者 Kirill KHVOROSTOVSKY WANG Hui-Jun 《Atmospheric and Oceanic Science Letters》 2009年第6期376-380,共5页
The relationship between the variability of the surface elevation of the Greenland Ice Sheet (GIS) in winter and sea level pressure is identified through analysis of data from satellite-borne radar altimeters, togethe... The relationship between the variability of the surface elevation of the Greenland Ice Sheet (GIS) in winter and sea level pressure is identified through analysis of data from satellite-borne radar altimeters, together with meteorological data fields during 1993 2005. We found that both the North Pacific Oscillation (NPO) and the North Atlantic Oscillation (NAO), the two major teleconnection patterns of the atmospheric surface pressure fields in the Northern Hemisphere, significantly influence the GIS winter elevation change. Further, it is suggested that the NPO may affect the GIS accumulation by influencing the NAO, particularly by changing the intensity and location of the Icelandic Low. 展开更多
关键词 Greenland ice sheet North Pacific Oscillation North Atlantic Oscillation atmospheric teleconnection patterns
下载PDF
Relationship between the Late Spring NAO and Summer Extreme Precipitation Frequency in the Middle and Lower Reaches of the Yangtze River 被引量:9
13
作者 TTIAN Bao-Qiang FAN Ke 《Atmospheric and Oceanic Science Letters》 2012年第6期455-460,共6页
The relationship between the late spring North Atlantic Oscillation (NAO) and the summer extreme precipitation frequency (EPF) in the middle and lower reaches of the Yangtze River Valley (MLYRV) is examined using an N... The relationship between the late spring North Atlantic Oscillation (NAO) and the summer extreme precipitation frequency (EPF) in the middle and lower reaches of the Yangtze River Valley (MLYRV) is examined using an NECP/NCAR reanalysis dataset and daily precipitation data from 74 stations in the MLYRV. The results show a significant negative correlation between the May NAO index and the EPF over the MLYRV in the subsequent summer. In positive EPF index years, the East Asian westerly jet shifts farther southward, and two blocking high positive anomalies appear over the Sea of Okhotsk and the Ural Mountains. These anomalies are favorable to the cold air from the mid-high latitudes invading the Yangtze River Valley (YRV). The moisture convergence and the ascending motion dominate the MLYRV. The above patterns are reversed in negative EPF index years. A wave train pattern that originates from the North Atlantic extends eastward to the Mediterranean and then moves to the Tibetan Plateau and from there to the YRV, which is an important link in the May NAO and the summer extreme precipitation in the MLYRV. The wave train may be aroused by the tripole pattern of the SST, which can explain why the May NAO affects the summer EPF in the MLYRV. 展开更多
关键词 North Atlantic Oscillation summer extreme precipitation frequency the middle and lower reaches of the Yangtze River Valley East Asian westerly jet
下载PDF
An enhanced influence of sea surface temperature in the tropical northern Atlantic on the following winter ENSO since the early 1980s 被引量:3
14
作者 CHEN Shang-Feng WU Renguang 《Atmospheric and Oceanic Science Letters》 CSCD 2017年第2期175-182,共8页
Previous studies have revealed a connection between springtime sea surface temperature (SST) in the tropical northern Atlantic (TNA) and the succeeding wintertime El Nino-Southern Oscillation (ENSO). The present... Previous studies have revealed a connection between springtime sea surface temperature (SST) in the tropical northern Atlantic (TNA) and the succeeding wintertime El Nino-Southern Oscillation (ENSO). The present analysis demonstrates that the linkage between springtime TNA SST and the following ENSO experiences an obvious interdecadal change around the early 1980s, with the connection being weak before but significant after. After the early 1980s, springtime positive TNA SST anomalies induce an anomalous cyclone over the northeastern subtropical Pacific and an anomalous Walker circulation with a descending branch over the tropical central-eastern Pacific. This leads to anomalous cold SST in the northeastern Pacific and an anomalous anticyclone over the western-central tropical Pacific, with anomalous easterlies to the equatorward side. As such, springtime TNA SST anomalies are followed by wintertime ENSO after the early 1980s. In contrast, before the early 1980s, anomalous cold SST in the northeastern Pacific and related anomalous easterlies over the western-central tropical Pacific are weak, corresponding to springtime positive TNA SST anomalies and resulting in a weak linkage between springtimeTNA SST and the succeeding wintertime ENSO. Further investigation implies that the change in the TNA SST-ENSO relationship is probably due to a change in springtime mean precipitation over the tropical Atlantic and South America. 展开更多
关键词 Tropical northern Atlantic ENSO interdecadal change mean precipitation
下载PDF
Dominant patterns of winter surface air temperature over Central Asia and their connection with atmospheric circulation
15
作者 Haishan Li Ke Fan 《Atmospheric and Oceanic Science Letters》 CSCD 2022年第6期1-8,共8页
The dominant patterns of the winter(December-February)surface air temperature anomalies(SATAs)over Central Asia(CA)are investigated in this study.The first two leading modes revealed by empirical orthogonal function(E... The dominant patterns of the winter(December-February)surface air temperature anomalies(SATAs)over Central Asia(CA)are investigated in this study.The first two leading modes revealed by empirical orthogonal function(EOF)analysis represent the patterns by explaining 74%of the total variance.The positive phase of EOF1 is characterized by a monopole pattern,corresponding to cold SATAs over CA,while the positive phase of EOF2 shows a meridional dipole pattern with warm and cold SATAs over northern and southern CA.EOF1 is mainly modulated by the negative phase of the Arctic Oscillation(AO)in the troposphere,and the negative AO phase may be caused by the downward propagation of the precursory anomalies of the stratospheric polar vortex.EOF2 is mainly influenced by the Ural blocking pattern and the winter North Atlantic Oscillation(NAO).The SATAs associated with EOF2 can be attributed to a dipole-like pattern of geopotential height anomalies over CA.The dipole-like pattern is mainly caused by the Ural blocking pattern,and the NAO can also contribute to the northern part of the dipole. 展开更多
关键词 Central asia Surface air temperature anomaly Arctic oscillation North atlantic oscillation Ural blocking
下载PDF
Sea surface temperature anomaly in the tropical North Atlantic during El Nino decaying years
16
作者 Xinyu Duan Feng Xue Fei Zheng 《Atmospheric and Oceanic Science Letters》 CSCD 2021年第6期14-19,共6页
Based on reanalysis data from 1979 to 2016,this study focuses on the sea surface temperature(SST)anomaly of the tropical North Atlantic(TNA)in El Nino decaying years.The TNA SST exhibits a clear warm trend during this... Based on reanalysis data from 1979 to 2016,this study focuses on the sea surface temperature(SST)anomaly of the tropical North Atlantic(TNA)in El Nino decaying years.The TNA SST exhibits a clear warm trend during this period.The composite result for 10 El Nino events shows that the TNA SST anomaly reaches its maximum in spring after the peak of an El Nino event and persists until summer.In general,the anomaly is associated with three factors-namely,El Nino,the North Atlantic Oscillation(NAO),and a long-term trend,leading to an increase in local SST up to 0.4℃,0.3℃,and 0.35℃,respectively.A comparison between 1983 and 2005 indicates that the TNA SST in spring is affected by El Niño,as well as the local SST in the preceding winter,which may involve a long-term trend signal.In addition,the lead-lag correlation shows that the NAO leads the TNA SST by 2-3 months.By comparing two years with an opposite phase of the NAO in winter(i.e.,1992 and 2010),the authors further demonstrate that the NAO is another important factor in regulating the TNA SST anomaly.A negative phase of the NAO in winter will reinforce the El Nino forcing substantially,and vise versa.In other words,the TNA SST anomaly in the decaying years is more evident if the NAO is negative with El Nino.Therefore,the combined effects of El Nino and the NAO must be considered in order to fully understand the TNA SST variability along with a long-term trend. 展开更多
关键词 Tropical North Atlantic Sea surface temperature anomaly North Atlantic Oscillation El Nino
下载PDF
Physical Mechanism of the Impacts of the Tropical Atlantic Sea Surface Temperature on the Decadal Change of the Summer North Atlantic Oscillation
17
作者 SUN Jian-Qi 《Atmospheric and Oceanic Science Letters》 CSCD 2013年第5期365-368,共4页
In this study,physical mechanism of the impacts of the tropical Atlantic sea surface temperature(SST)on decadal change of the summer North Atlantic Oscillation(SNAO)was explored using an atmospheric general circulatio... In this study,physical mechanism of the impacts of the tropical Atlantic sea surface temperature(SST)on decadal change of the summer North Atlantic Oscillation(SNAO)was explored using an atmospheric general circulation model(AGCM)developed at the International Centre for Theoretical Physics(ICTP).The simulation results indicate that the decadal warming of the SST over the tropical Atlantic after the late 1970s could have significantly enhanced the convection over the region.This enhanced convection would have strengthened the local meridional circulation over the Eastern Atlantic-North Africa-Western Europe region,exciting a meridional teleconnection.This teleconnection might have brought the signal of the tropical Atlantic SST to the Extratropics,consequently activating the variability of the eastern part of the SNAO southern center,which led to an eastward shift of the SNAO southern center around the late 1970s.Such physical processes are highly consistent with the previous observations. 展开更多
关键词 summer North Atlantic Oscillation tropical Atlantic sea surface temperature TELECONNECTION decadal change SIMULATION
下载PDF
Introducing driving-force information increases the predictability of the North Atlantic Oscillation
18
作者 PAN Xinnong WANG Geli YANG Peicai 《Atmospheric and Oceanic Science Letters》 CSCD 2019年第5期329-336,共8页
The North Atlantic Oscillation(NAO)is the most prominent mode of atmospheric variability in the Northern Hemisphere.Because of the close relationship between the NAO and regional climate in Eurasia,North Atlantic,and ... The North Atlantic Oscillation(NAO)is the most prominent mode of atmospheric variability in the Northern Hemisphere.Because of the close relationship between the NAO and regional climate in Eurasia,North Atlantic,and North America,improving the prediction skill for the NAO has attracted much attention.Previous studies that focused on the predictability of the NAO were often based upon simulations by climate models.In this study,the authors took advantage of Slow Feature Analysis to extract information on the driving forces from daily NAO index and introduced it into phase-space reconstruction.By computing the largest Lyapunov exponent,the authors found that the predictability of daily NAO index shows a significant increase when its driving force signal is considered.Furthermore,the authors conducted a short-term prediction for the NAO by using a global prediction model for chaotic time series that incorporated the driving-force information.Results showed that the prediction skill for the NAO can be largely increased.In addition,results from wavelet analysis suggested that the driving-force signal of the NAO is associated with three basic drivers:the annual cycle(1.02 yr),the quasi-biennial oscillation(QBO)(2.44 yr);and the solar cycle(11.6 yr),which indicates the critical roles of the QBO and solar activities in the predictability of the NAO. 展开更多
关键词 North Atlantic Oscillation slow feature analysis driving force characteristics time series prediction
下载PDF
Ensemble Simulations of a Nonlinear Barotropic Model for the North Atlantic Oscillation
19
作者 ZHANG Dong-Bin JIN Fei-Fei +1 位作者 LI Jian-Ping DING Rui-Qiang 《Atmospheric and Oceanic Science Letters》 2010年第5期277-282,共6页
A numerical ensemble-mean approach was employed to solve a nonlinear barotropic model with chastic basic flows to analyze the nonlinear effects in the formation of the North Atlantic Oscillation (NAO). The nonlinear... A numerical ensemble-mean approach was employed to solve a nonlinear barotropic model with chastic basic flows to analyze the nonlinear effects in the formation of the North Atlantic Oscillation (NAO). The nonlinear response to external forcing was more similar to the NAO mode than the linear response was, indicating the importance of nonlinearity. With increasing external forcing and enhanced low-frequency anomalies, the effect of nonlinearity increased. Therefore, for strong NAO events, nonlinearity should be considered. 展开更多
关键词 ensemble-mean NAO NONLINEARITY
下载PDF
The Interrelation between the NAO (North Atlantic Oscillation) and Regulated River Discharges at the Baltic Sea Drainage Basin
20
作者 Ali Bassal Mahmood 《Journal of Earth Science and Engineering》 2014年第6期331-351,共21页
Both winter DJF (December, January, February) months and DJF season means long-term data series of 50 regulated rivers discharges rates and the NAO indices were analyzed for different spans. This study is dictated ... Both winter DJF (December, January, February) months and DJF season means long-term data series of 50 regulated rivers discharges rates and the NAO indices were analyzed for different spans. This study is dictated for: (1) detecting the exclusive impacts of the positive phases of NAO indices on rivers discharges rates by estimating the Linear Correlation Coefficient; (2) modeling the interrelations between the discharges rates and NAO indices by estimating the Linear Regression Models, both for manifesting the impact of the positive phase of NAO index; (3) estimating the Linear Trend Coefficient in the discharge series, for manifesting the contribution of the positive phase of NAO index. Discharge rates are mainly influenced by the two mechanisms: the positive phase of NAO index and the environmental conditions in specific catchments, that is where, the positive phase of the NAO index manifest its impact on the related rivers discharges and its contribution in the related configured trends. The discharges fluctuations patterns show some increase in the discharges values have been occurred in regions around the Northern Baltic Proper as well as in Southern Finland and Sweden. The rivers such as Lagan, Nissan, Helgean, Venta, Pamu, Porvoonjoki, Lapuanjoki, Oulujoki, Kyronjoki, Wisla, Eurajoki, Odra, Lielupe, Gota alv, Motala strom, Nykopingsan, Vuoksi, Kalajoki and Simojoki haven not linear discharges changes registered depending on the specificity of the environmental conditions at the catchments areas for those rivers. The positive phase of NAO index has a linear relation with impacted river discharge. 展开更多
关键词 River discharge NAO statistical analysis climate.
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部