Correlation between El Niño–Southern Oscillation (ENSO) and precipitation in South‐east Asia and the Pacific region     

Z. X. Xu  K. Takeuchi  H. Ishidaira 《水文研究》2004,18(1):107-123

The relationship between El Niño–Southern Oscillation (ENSO) events versus precipitation anomalies, and the response of seasonal precipitation to El Niño and La Niña events were investigated for 30 basins that represent a range of climatic types throughout South‐east Asia and the Pacific region. The teleconnection between ENSO and the hydroclimate is tested using both parametric and non‐parametric approaches, and the lag correlations between precipitation anomalies versus the Southern Oscillation Index (SOI) several months earlier, as well as the coherence between SOI and precipitation anomalies are estimated. The analysis shows that dry conditions tend to be associated with El Niño in the southern zone, and part of the middle zone in the study area. The link between precipitation anomalies and ENSO is statistically significant in the southern zone and part of the middle zone of the study area, but significant correlation was not observed in the northern zone. Patterns of precipitation response may differ widely among basins, and even the response of a given river basin to individual ENSO events also may be changeable. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Long‐term trend of precipitation in China and its association with the El Niño–southern oscillation     

Z. X. Xu  J. Y. Li  K. Takeuchi  H. Ishidaira 《水文研究》2007,21(1):61-71

The plausible long‐term trend of precipitation in China and its association with El Niño–southern oscillation (ENSO) are investigated by using non‐parametric techniques. It is concluded that a greater number of decreasing trends are observed than are expected to occur by chance. Geographically, the decreasing trend was concentrated in most parts of China, including the Songliao River, Hai River, Huai River, Yellow River, Zhujiang River, and southern part of the Yangtze River basins, whereas an increasing trend appeared primarily in the western and middle parts of China, mainly including the Inland River basin, and the northern part of the Yangtze River basins. Monthly mean precipitation for the summer and early autumn months generally decreased, with the greatest decrease occurring in August. The precipitation in spring from January to April and later autumn, including September and October, tended to increase. The teleconnection between precipitation and ENSO has been investigated by using the non‐parametric Kendall's τ. The correlation coefficients between the southern oscillation index (SOI) and precipitation show the areas with positive or negative associations. Approximately 20% of the stations exhibit statistically significant correlations between SOI and precipitation, of which 70% show a negative correlation, with most of them appearing in southeast China and several appearing in northwest and northeast China. Similar regional patterns are also observed when the precipitation records are further subdivided into El Niño, La Niña, and neutral periods. Statistical tests for the three kinds of time series were carried out using the non‐parametric Wilcoxon rank‐sum test, and it is noted that the stations with significant differences in precipitation averages are mainly marked in the Yellow River basin and south China. The frequencies of below‐ and above‐average precipitation that occurred during the El Niño, La Niña, and neutral periods are estimated as well. The result shows that greater precipitation may be associated with El Niño episodes in south China, but drought may easily occur during El Niño episodes in the Yellow River basin. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Influence of the El Niño/Southern Oscillation on South Korean streamflow variability          下载免费PDF全文

Jai Hong Lee  Pierre Y. Julien 《水文研究》2017,31(12):2162-2178

Deciphering the mechanisms through which the El Niño/Southern Oscillation (ENSO) affects hydrometeorological parameters in the tropics and extratropics is of great interest. We investigate climatic teleconnections between warm or cold phases of ENSO and streamflow patterns over South Korea using an empirical methodology designed to detect regions showing a strong and consistent hydroclimatic signal associated with ENSO. We calculate not only spatial coherence values by monthly streamflow composite formed over 2‐year ENSO cycle and the first harmonic fit to detect candidate regions but also temporal consistency rates by aggregate composite and index time series to determine core regions. As a result, the core regions, namely, the Han river basin and the Nakdong river basin, are detected with a high level of response of ENSO phenomena to streamflow patterns. The ENSO composites for both core regions indicate drier (wetter) conditions in early autumn of the warm (cold) episode years and wetter (drier) conditions from winter to spring of the following year. For both regions, the spatial coherences are over 92% (82%) and the temporal consistencies are 71% (75%) during the El Niño (La Niña) events. In addition, for the core regions identified by composite‐harmonic analysis for both extreme episodes, the results of comparative analyses by using correlation, annual cycle, and Wilcoxon rank sum test indicate that 2 opposite phases‐streamflow relationships have a tendency of sign reversal of the streamflow anomaly. Also, the positive departures during the El Niño years show more coherent and strong responses than the negative anomalies in the La Niña events. In conclusion, South Korea experiences climatic teleconnection between ENSO forcing and midlatitude streamflow patterns.  相似文献   

Long‐term trend analysis for precipitation in Asian Pacific FRIEND river basins     

Z. X. Xu  K. Takeuchi  H. Ishidaira  J. Y. Li 《水文研究》2005,19(18):3517-3532

In order to analyse the long‐term trend of precipitation in the Asian Pacific FRIEND region, records from 30 river basins to represent the large range of climatic and hydrological characteristics in the study area are selected. The long‐term trend in precipitation time series and its association with the southern oscillation index (SOI) series are investigated. Application of the nonparametric Mann–Kendall test for 30 precipitation time series has shown that only four of these 30 time series have a long‐term trend at the 5% level of significance. Nevertheless, most of the records tend to decrease over the last several decades. The dataset is further divided geographically into northern, middle, and southern zones, with 20°N and 20°S latitude as the dividing lines. The middle zone has the greatest variation and the southern zone the least variation over the past century. Also, the southern zone has greater variation during the past 30 years. The association between precipitation and SOI is investigated by dividing the precipitation records of each station into El Niño, La Niña, and neutral periods. The Wilcoxon rank‐sum test showed that differences in precipitation for the three classes were most marked in the southern zone of the study area. The frequencies of below‐ and above‐average precipitation for El Niño, La Niña, and neutral periods are estimated for the 30 precipitation time series as well. The results show that the frequencies of precipitation under each set of conditions, with lower precipitation generally associated with El Niño periods in the southern zone. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Influence of SOI, DMI and Niño3.4 on South Australian rainfall   总被引：1，自引：0，他引：1  

Rezaul K. Chowdhury  Simon Beecham 《Stochastic Environmental Research and Risk Assessment (SERRA)》2013,27(8):1909-1920

The influences of climate drivers (SOI, DMI and Niño3.4) on South Australian (SA) rainfall are investigated in this study. Recent records of monthly rainfall and climate driver index values from 1981 to 2010 were analysed for 53 rainfall stations, located across eight SA natural resources management (NRM) regions. The Pearson, Kendall and Spearman correlation tests were applied between rainfall and climate drivers and between the climate drivers themselves. Both SA summer (December to February) and autumn (March to May) rainfalls were found not significantly influenced by climate indices. Winter rainfall in the south and east parts of SA was found strongly influenced by both SOI and DMI, particularly in July and August. Both SOI and DMI are inter-correlated in winter. Spring rainfall was found significantly influenced by DMI in the south and east parts of SA, particularly in September and October. In terms of ENSO phenomena, whilst both SOI and Niño3.4 are correlated, SOI was found more to be influential than Niño3.4 for SA winter and spring rainfall. Outcomes of the study are useful for stochastic rainfall generation and for developing downscaling techniques to generate rainfall projections in the region.  相似文献   

Impacts of El Niño–southern oscillation on global runoff: Characteristic signatures and potential mechanisms     

Yuanyuan You  Jianyu Liu  Yongqiang Zhang  Hylke E. Beck  Xihui Gu  Dongdong Kong 《水文研究》2021,35(10):e14367

Runoff signatures, including low flow, high flow, mean flow and flow variability, have important implications on the environment and society, predominantly through drought, flooding and water resources. Yet, the response of runoff signatures has not been previously investigated at the global scale, and the influencing mechanisms are largely unclear. Hence, this study makes a global assessment of runoff signature responses to the El Niño and La Niña phases using daily streamflow observations from 8217 gauging stations during 1960–2015. Based on the Granger causality test, we found that ~15% of the hydrological stations of multiple runoff signatures show a significant causal relationship with El Niño–southern oscillation (ENSO). The quantiles of all runoff signatures were larger during the El Niño phase than during the La Niña phase, implying that the entire flow distribution tends to shift upward during El Niño and downward during La Niña. In addition, El Niño has different effects on low and high flows: it tends to increase the low and mean flow signatures but reduces the high flow and flow variability signatures. In contrast, La Niña generally reduces all runoff signatures. We highlight that the impacts of ENSO on streamflow signatures are manifested by its effects on precipitation (P), potential evaporation (PET) and leaf area index (LAI) through ENSO-induced atmospheric circulation changes. Overall, our study provides a comprehensive picture of runoff signature responses to ENSO, with valuable insights for water resources management and flood and drought disaster mitigation.  相似文献   

El Niño and La Niña influence on mean river flows of southern South America in the 20th century     

Guillermo J. Berri  Emilio Bianchi  Gabriela V. Müller 《水文科学杂志》2019,64(8):900-909

The influence of the El Niño Southern Oscillation (ENSO) phenomenon on monthly mean river flows of 12 rivers in the extreme south of South America in the 20th century is analysed. The original dataset of each river is divided into two subsets, i.e. warm ENSO events or El Niño, and cold ENSO events or La Niña. The elements of the subsets are composites of 24 consecutive months, from January of the year when the ENSO event begins to December of the following year. The ENSO signal is analysed by comparing the monthly mean value of each subset to the long-term monthly mean. The results reveal that, in general, monthly mean El Niño (La Niña) river flows are predominantly larger (smaller) than the long-term monthly mean in the rivers studied. The anomalies are more evident during the second half of the year in which the event starts and the first months of the following year.  相似文献   

Low‐frequency modulation and trend of the relationship between ENSO and precipitation along the northern to centre Peruvian Pacific coast          下载免费PDF全文

Luc Bourrel  Pedro Rau  Boris Dewitte  David Labat  Waldo Lavado  Aude Coutaud  Andrea Vera  Abigail Alvarado  Julio Ordoñez 《水文研究》2015,29(6):1252-1266

The relationship between El Niño Southern Oscillation (ENSO) and precipitation along the Peruvian Pacific coast is investigated over 1964–2011 on the basis of a variety of indices accounting for the different types of El Niño events and atmospheric and oceanographic manifestations of the interannual variability in the tropical Pacific. We show the existence of fluctuations in the ENSO/precipitation relationship at decadal timescales that are associated with the ENSO property changes over the recent decades. Several indices are considered in order to discriminate the influence of the two types of El Niño, namely, the eastern Pacific El Niño and the central Pacific El Niño, as well as the influence of large‐scale atmospheric variability associated to the Madden and Julian Oscillation, and of regional oceanic conditions. Three main periods are identified that correspond to the interleave periods between the main climatic transitions over 1964–2011, i.e. the shifts of the 1970s and the 2000s, over which ENSO experiences significant changes in its characteristics. We show that the relationship between ENSO and precipitation along the western coast of Peru has experienced significant decadal change. Whereas El Niño events before 2000 lead to increased precipitation, in the 2000s, ENSO is associated to drier conditions. This is due to the change in the main ENSO pattern after 2000 that is associated to cooler oceanic conditions off Peru during warm events (i.e. central Pacific El Niño). Our analysis also indicates that the two extreme El Niño events of 1982/1983 and 1997/1998 have overshadowed actual trends in the relationship between interannual variability in the tropical Pacific and precipitation along the coast of Peru. Overall, our study stresses on the complexity of the hydrological cycle on the western side of the Andes with regard to its relationship with the interannual to decadal variability in the tropical Pacific. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Teleconnection between ENSO and climate in South China   总被引：2，自引：1，他引：1  

Qinglan Li  Ji Chen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(4):927-941

This study investigates the features of the teleconnection between El Niño–Southern Oscillation (ENSO) and the climate over the region with the latitude from 21°N to 25°N and longitude from 111°E to 116°E in South China for the period from 1960 to 2005. The climate variables analyzed are the monthly means of daily maximum temperature (Tmax), minimum temperature (Tmin), precipitation and relative humidity (RH), which are recorded at 20 weather stations over the region. The cross correlation coefficients between the ENSO index and those climate variable anomalies are calculated to evaluate the strength of the teleconnection. The analysis results reveal that ENSO has positive influence on most of the climate variables in the study region. Specifically, ENSO has significant effects on Tmin (but not Tmax) with the corresponding time delay of about 4 months. In addition, ENSO has considerable influence on precipitation and RH over the study region with teleconnection lag time of around 2 and 1 month, respectively.  相似文献   

REPORT ON THE ACTIVITIES OF THE INTERNATIONAL COMMISSION ON WATER QUALITY FOR THE PERIOD 1971–1975     

M. G. VALYASHKO 《水文科学杂志》2013,58(4):429-431

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The influences of the Southern and North Atlantic Oscillations on climatic surface variables in Turkey     

M. aatay Karabrk  Ercan Kahya  Mehmet Karaca 《水文研究》2005,19(6):1185-1211

In this study, Turkish climatic variables (precipitation, stream flow and maximum and minimum temperatures) were first analysed in association with both the Southern Oscillation (SO) and the North Atlantic Oscillation (NAO). The relationships between Turkish maximum and minimum monthly temperatures and the extreme phases of the SO (El Niño and La Niña events) were examined. The results of this analysis showed that relationships between Turkish monthly maximum temperatures and El Niño and La Niña contain some complexity still to be identified, because both events produce a signal indicating a correspondence with cold anomalies in the aggregate composites. A relationship between turkish minimum temperatures and El Niño was detected in western Anatolia, whereas there was no significant and consistent signal associated with La Niña. Moreover a series of cross‐correlation analyses was carried out to demonstrate the teleconnections between the climatic variables and both the NAO and SO. The NAO during winter was found to influence precipitation and stream‐flow patterns. In contrast temperature patterns appeared to be less sensitive to the NAO. Furthermore, lag‐correlation results indicated a prediction potential for both precipitation and stream‐flow variables in connection with the NAO. Simultaneous and time‐lag correlations between the climatic variables and the SO index, in general, indicated weaker relationships in comparison with those for the NAO. These analyses also showed that the influences of the SO on Turkish temperature data are negligible. The outcomes were presented in conjunction with an explanation regarding physical mechanisms behind the implied teleconnections. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Global ENSO-streamflow teleconnection,streamflow forecasting and interannual variability     

FRANCIS H. S. CHIEW  THOMAS A. McMAHON 《水文科学杂志》2013,58(3):505-522

Abstract

El Niño Southern Oscillation (ENSO) has been linked to climate anomalies throughout the world. This paper presents an overview of global ENSO-streamflow teleconnection and identifies regions where the relationship may be exploited to forecast streamflow several months ahead. The teleconnection is investigated by fitting a first harmonic to 24-month El Niño streamflow composites from 581 catchments worldwide and the potential for forecasting is investigated by calculating the lag correlation between streamflow and two indicators of ENSO. The analyses indicate clear ENSO-streamflow teleconnections in many catchments, some of which are consistent across large geographical regions. Strong and regionally consistent ENSO-streamflow teleconnections are identified in Australia and New Zealand, South and Central America, and weaker signals are identified in some parts of Africa and North America. The results suggest that the ENSO-streamflow relationship and the serial correlation in streamflow can be used to successfully forecast streamflow. The streamflow forecasts can be used to help manage water resources, particularly in systems with high interannual variability in Australia, southern and drier parts of Africa and some areas of North America.  相似文献   

Influences of local hydroclimatology and teleconnections on Florida's precipitation and temperature variability     

Priyank J. Sharma  Ramesh S. V. Teegavarapu 《水文研究》2021,35(9):e14347

Understanding the influences of local hydroclimatology and two large-scale oceanic-atmospheric oscillations (i.e., Atlantic Multidecadal Oscillation (AMO) and El Niño-Southern Oscillation (ENSO)) on seasonal precipitation (P) and temperature (T) relationships for a tropical region (i.e., Florida) is the focus of this study. The warm and cool phases of AMO and ENSO are initially identified using sea surface temperatures (SSTs). The associations of SSTs and regional minimum, maximum and average surface air temperatures (SATs) with precipitation are then evaluated. The seasonal variations in P-SATs and P-SSTs associations considering AMO and ENSO phases for sites in (1) two soil temperature regimes (i.e., thermic and hyperthermic); (2) urban and non-urban regions; and (3) regions with and without water bodies, are analysed using two monthly datasets. The analyses are carried out using trend tests, two association measures, nonparametric and parametric statistical hypothesis tests and kernel density estimates. Decreasing (increasing) trend in precipitation (SATs) is noted in the recent multi-decadal period (1985–2019) compared to the previous one (1950–1984) indicating a progression towards warmer and drier climatic conditions across Florida. Spatially and temporally non-uniform variations in the associations of precipitation with SATs and SSTs are noted. Strong positive (weak negative) P–T associations are noted during the wet (dry) season for both AMO phases and El Niño, while significant (positive) P–T associations are observed across southern Florida during La Niña in the dry season. The seasonal influences are predominant in governing the P–T relationship over the regions with and without water bodies; however, considerable variations between El Niño and La Niña are noted during the dry season. The climate variability influences on P–T correlations for hyperthermic and thermic soil zones are found to be insignificant (significant) during the wet (dry) season. Nonparametric clustering is performed to identify the spatial clusters exhibiting homogeneous P–T relationships considering seasonal and climate variability influences.  相似文献   

Regional sea-surface temperatures explain spatial and temporal variation of summer precipitation in the source region of the Yellow River     

Feifei Yuan  Hiroshi Yasuda  Ronny Berndtsson  Cintia Bertacchi Uvo  Linus Zhang  Zhenchun Hao 《水文科学杂志》2013,58(8):1383-1394

ABSTRACT

The summer precipitation (June–September) in the source region of the Yellow River accounts for about 70% of the annual total, playing an important role in water availability. This study divided the source region of the Yellow River into homogeneous zones based on precipitation variability using cluster analysis. Summer precipitation trends and teleconnections with global sea-surface temperatures (SST) and the Southern Oscillation Index (SOI) from 1961 to 2010 were investigated by Mann-Kendall test and Pearson product-moment correlation analysis. The results show that the northwest part (Zone 1) had a non-significantly increasing trend, and the middle and southeast parts (zones 2 and 3) that receive the most precipitation displayed a statistically significant decreasing trend for summer precipitation. The summer precipitation in the whole region showed statistically significant negative correlations with the central Pacific SST for 0–4 month lag and with the Southern Indian and Atlantic oceans SST for 5–8 month lag. Analyses of sub-regions reveal intricate and complex correlations with different SST areas that further explain the summer precipitation variability. The SOI had significant positive correlations, mainly for 0–2 months lag, with summer precipitation in the source region of the Yellow River. It is seen that El Niño Southern Oscillation (ENSO) events have an influence on summer precipitation, and the predominant negative correlations indicate that higher SST in equatorial Pacific areas corresponding to El Niño coincides with less summer precipitation in the source region of the Yellow River.