scholarly journals Effects of ENSO on the major ion record of a Qomolangma (Mount Everest) ice core

2016 ◽  
Vol 57 (71) ◽  
pp. 282-288 ◽  
Author(s):  
Hao Xu ◽  
Shugui Hou ◽  
Hongxi Pang ◽  
Chaomin Wang
Keyword(s):  
Time Series ◽  
Major Ions ◽  
Southern Oscillation ◽  
Ice Core ◽  
Wavelet Coherence ◽  
Mount Everest ◽  
Ion Concentrations ◽  
Major Ion ◽  
Asian Monsoons ◽  
Wavelet Coherence Analysis

AbstractCorrelations between a 1000 year record of the major ions in a 108.83 m ice core from East Rongbuk Glacier (28°01’N, 86°58’E; 6518ma.s.l.) on the northeast slope of Qomolangma (Mount Everest) and the Southern Oscillation Index (SOI) were examined to investigate possible links between the ice-core records of the southern Tibetan Plateau (TP) and El Niño Southern Oscillation (ENSO). The results show that years with the highest crustal ion concentrations and lowest marine ion concentrations corresponded with a low SOI, and vice versa. Cross wavelet and wavelet coherence analysis between major ion time series and the SOI indicated that there were significant sections with high common power between the major ion time series and the SOI, suggesting a correlation between the ion records of the Qomolangma ice core and ENSO. Further investigation indicated that the higher SOI years corresponded with weaker continental air masses and stronger south Asian monsoons over the southern TP, leading to increased marine ions and decreased continental ions transported to the southern TP. The in-phase surface pressure anomalies of the southern TP and Darwin, Australia, link ENSO and ion transport over the southern TP, and thus suggest a link between aerosol transport over the southern TP and ENSO.

scholarly journals Response of regional climate and glacier ice proxies to El Niño-Southern Oscillation (ENSO) in the subtropical Andes

2008 ◽  
Vol 4 (1) ◽  
pp. 173-211
Author(s):  
E. Dietze ◽  
A. Kleber ◽  
M. Schwikowski
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Ice Core ◽  
La Niña ◽  
El Nino Southern Oscillation ◽  
Ion Concentrations ◽  
Major Ion ◽  
La Nina ◽  
Glacier Ice

Abstract. El Niño-Southern Oscillation (ENSO) is an important element of earth's ocean-climate system. To further understand its past variability, proxy records from climate archives need to be studied. Ice cores from high alpine glaciers may contain high resolution ENSO proxy information, given the glacier site is climatologically sensitive to ENSO. We investigated signals of ENSO in the climate of the subtropical Andes in the proximity of Cerro Tapado glacier (30°08' S, 69°55' W, 5550 m a.s.l.), where a 36 m long ice core was drilled in 1999 (Ginot, 2001). We used annual and semi-annual precipitation and temperature time series from regional meteorological stations and interpolated grids for correlation analyses with ENSO indices and ice core-derived proxies (net accumulation, stable isotope ratio δ18O, major ion concentrations). The total time period investigated here comprises 1900 to 2000, but varies with data sets. Only in the western, i.e. Mediterranean Andes precipitation is higher (lower) during El Niño (La Niña) events, especially at higher altitudes, due to the latitudinal shift of frontal activity during austral winters. However, the temperature response to ENSO is more stable in space and time, being higher (lower) during El Niño (La Niña) events in most of the subtropical Andes all year long. From a northwest to southeast teleconnection gradient, we suggest a regional water vapour feedback triggers temperature anomalies as a function of ENSO-related changes in regional pressure systems, Pacific sea surface temperature and tropical moisture input. Tapado glacier ice proxies are found to be predominantly connected to eastern Andean summer rain climate, which contradicts previous studies and the modern mean spatial boundary between subtropical summer and winter rain climate derived from the grid data. The only ice core proxy showing a response to ENSO is the major ion concentrations, via local temperature indicating reduced sublimation and mineral dust input during El Niño years.

scholarly journals Asian–Pacific Oscillation signal from a Qomolangma (Mount Everest) ice-core chemical record

2014 ◽  
Vol 55 (66) ◽  
pp. 121-128 ◽  
Author(s):  
Hao Xu ◽  
Shugui Hou ◽  
Hongxi Pang
Keyword(s):  
North Pacific ◽  
Major Ions ◽  
Ice Core ◽  
Mount Everest ◽  
Asian Continent ◽  
Major Ion ◽  
The North ◽  
Asian Pacific ◽  
The North Pacific ◽  
Highly Loaded

AbstractThe Asian–Pacific Oscillation (APO) is a climate pattern related to the thermal differences between the Asian continent and the north Pacific. We present a 1000 year record of the major ions in a 108.83 m ice core from east Rongbuk glacier (28°01′ N, 86°58′ E; 6518ma.s.l.) on the northeast slope of Qomolangma (Mount Everest), and discuss its relationship with a 993 year time series of the summer APO index that has been reconstructed from Beijing’s summer temperature (recorded by a stalagmite) and the Pacific Decadal Oscillation (PDO) index. Empirical orthogonal function (EOF) analysis shows that crustal major ions (Mg2+, Ca2+, SO42– and NO3–) are highly loaded on EOF1, whereas marine major ions (Cl– and Na+) are highly loaded on EOF2. Higher EOF1 is associated with lower upper-troposphere temperature (UTT) over Mongolia, corresponding to a lower APO index and higher surface pressure. Higher EOF2 is associated with higher UTT over Mongolia, corresponding to a higher APO index and lower surface pressure. The higher burden of major ions and higher summer APO index during the period AD 1000–1323 may be due to drought and warm climate of the major-ion source regions. From AD1323 to 1900, EOF1 and EOF2 do not show a consistent correlation with summer APO index, indicating the complex mechanisms of ion transport over the southern Tibetan Plateau (TP) during this period. After AD 1900, the summer APO index is correlated negatively with EOF1 and positively with EOF2, indicating that ion transport over the southern TP during this period is influenced significantly by the APO. Our examinations of the PDO index and major-ion record show that higher PDO corresponds to higher EOF1 and lower EOF2. This suggests that the correlation between the recorded major-ion concentration and the APO index originates in the seesaw relationship in temperature between the Asian continent and the north Pacific.

scholarly journals Assessment of Spatial Variability of Major-Ion Concentrations and DEL Oxygen-18 Values in Surface Snow, Upper Fremont Glacier, Wyoming, U.S.A.

1994 ◽  
Vol 25 (5) ◽  
pp. 371-388 ◽  
Author(s):  
D. L. Naftz ◽  
P. F. Schuster ◽  
M. M. Reddy
Keyword(s):  
Little Ice Age ◽  
Major Ions ◽  
Ice Core ◽  
Chemical Constituent ◽  
Ice Age ◽  
Snow Layer ◽  
Geographic Scale ◽  
Ion Concentrations ◽  
Major Ion ◽  
Surface Snow

One hundred samples were collected from the surface of the Upper Fremont Glacier at equally spaced intervals defined by an 8,100 m2 snow grid to assess the significance of lateral variability in major-ion concentrations and del oxygen-18 values. For the major ions, the largest concentration range within the snow grid was sodium (0.5056 mg/l) and the smallest concentration range was sulfate (0.125 mg/l). Del oxygen-18 values showed a range of 7.45 per mil. Comparison of the observed variability of each chemical constituent to the variability expected by measurement error indicated substantial lateral variability within the surface-snow layer. Results of the nested ANOVA indicate most of the variance for every constituent is in the values grouped at the two smaller geographic scales (between 506 m2 and within 506 m2 sections). Calcium and sodium concentrations and del oxygen-18 values displayed the largest amount of variance at the largest geographic scale (between 2,025 m2 sections) within the grid and ranged from 14 to 26 per cent of the total variance. The variance data from the snow grid were used to develop equations to evaluate the significance of both positive and negative concentration/value peaks of nitrate and del oxygen-18 with depth, in a 160 m ice core. Solving the equations indicates that both the nitrate and del oxygen-18 ice-core profiles have concentration/value trends that exceed the limits expected from lateral variability. Values of del oxygen-18 in the section from 110-150 m below the surface consistently vary outside the expected limits and possibly represents cooler temperatures during the Little Ice Age from about 1810 to 1725 A.D.

scholarly journals Teleconnections between Monthly Rainfall Variability and Large-Scale Climate Indices in Southwestern Colombia

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1863 ◽  
Author(s):  
Teresita Canchala ◽  
Wilfredo Alfonso-Morales ◽  
Wilmar Loaiza Cerón ◽  
Yesid Carvajal-Escobar ◽  
Eduardo Caicedo-Bravo
Keyword(s):  
Water Resources ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
Monthly Rainfall ◽  
Wavelet Coherence ◽  
Climate Indices ◽  
Annual Scale ◽  
Wavelet Coherence Analysis

Given that the analysis of past monthly rainfall variability is highly relevant for the adequate management of water resources, the relationship between the climate-oceanographic indices, and the variability of monthly rainfall in Southwestern Colombia at different time scales was chosen as the research topic. It should also be noted that little-to-no research has been carried out on this topic before. For the purpose of conducting this research, we identified homogeneous rainfall regions while using Non-Linear Principal Component Analysis (NLPCA) and Self-Organizing Maps (SOM). The rainfall variability modes were obtained from the NLPCA, while their teleconnection in relation to the climate indices was obtained from Pearson’s Correlations and Wavelet Transform. The regionalization process clarified that Nariño has two regions: the Andean Region (AR) and the Pacific Region (PR). The NLPCA showed two modes for the AR, and one for the PR, with an explained variance of 75% and 48%, respectively. The correlation analyses between the first nonlinear components of AR and PR regarding climate indices showed AR high significant positive correlations with Southern Oscillation Index (SOI) index and negative correlations with El Niño/Southern Oscillation (ENSO) indices. PR showed positive ones with Niño1 + 2, and Niño3, and negative correlations with Niño3.4 and Niño4, although their synchronous relationships were not statistically significant. The Wavelet Coherence analysis showed that the variability of the AR rainfall was influenced principally by the Niño3.4 index on the 3–7-year inter-annual scale, while PR rainfall were influenced by the Niño3 index on the 1.5–3-year inter-annual scale. The El Niño (EN) events lead to a decrease and increase in the monthly rainfall on AR and PR, respectively, while, in the La Niña (LN) events, the opposite occurred. These results that are not documented in previous studies are useful for the forecasting of monthly rainfall and the planning of water resources in the area of study.

scholarly journals Comparison of two ice-core chemical records recovered from the Qomolangma (Mount Everest) region, Himalaya

2002 ◽  
Vol 35 ◽  
pp. 266-272 ◽  
Author(s):  
Shugui Hou ◽  
Dahe Qin ◽  
Dongqi Zhang ◽  
Jiawen Ren ◽  
Shichang Kang ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Seasonal Variations ◽  
Monsoon Season ◽  
Ice Core ◽  
Far East ◽  
Mount Everest ◽  
Snow Layer ◽  
Ion Concentrations ◽  
The Mean

AbstractA 40.9 m ice core was recovered from Far East Rongbuk Glacier (FER), Qomolangma (Mount Everest), Himalaya, and an 80.4 m core from neighboring East Rongbuk Glacier (ER). Both are dated by seasonal variations of δ18O and major-ionic profiles, together with references of β-activity peaks. In this paper we compare the chemical records of these two cores to show post-depositional modification processes. The smoothed β18O profiles of the two cores show a similar trend. However, the mean β18O value of the FER core for the period 1954—96 is 3.12%o less than that of the corresponding part of the ER core, and the major-ionic profiles of the two cores differ considerably. We suggest that melting-away of the snow layer deposited during the pre-monsoon season may account for lower β18O values of the FER than of the ER core, and higher terrestrial ion concentrations in the FER core for the period 1957-63 may contribute to changes by chemical reactions in the presence of snowmelting. The significantly decreased NH4 and, to a lesser degree, SO42 concentrations in the FER core could be caused by the ion elution process that moved most chemicals away with runoff.

scholarly journals A skewed perspective of the Indian rainfall–El Niño–Southern Oscillation (ENSO) relationship

2020 ◽  
Vol 24 (11) ◽  
pp. 5473-5489 ◽  
Author(s):  
Justin Schulte ◽  
Frederick Policielli ◽  
Benjamin Zaitchik
Keyword(s):  
Time Series ◽  
Time Domain ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Wavelet Coherence ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
The Time Domain ◽  
Time Domain Correlation

Abstract. Wavelet coherence is a method that is commonly used in hydrology to extract scale-dependent, nonstationary relationships between time series. However, we show that the method cannot always determine why the time-domain correlation between two time series changes in time. We show that, even for stationary coherence, the time-domain correlation between two time series weakens if at least one of the time series has changing skewness. To overcome this drawback, a nonlinear coherence method is proposed to quantify the cross-correlation between nonlinear modes embedded in the time series. It is shown that nonlinear coherence and auto-bicoherence spectra can provide additional insight into changing time-domain correlations. The new method is applied to the El Niño–Southern Oscillation (ENSO) and all-India rainfall (AIR), which is intricately linked to hydrological processes across the Indian subcontinent. The nonlinear coherence analysis showed that the skewness of AIR is weakly correlated with that of two ENSO time series after the 1970s, indicating that increases in ENSO skewness after the 1970s at least partially contributed to the weakening ENSO–AIR relationship in recent decades. The implication of this result is that the intensity of skewed El Niño events is likely to overestimate India's drought severity, which was the case in the 1997 monsoon season, a time point when the nonlinear wavelet coherence between AIR and ENSO reached its lowest value in the 1871–2016 period. We determined that the association between the weakening ENSO–AIR relationship and ENSO nonlinearity could reflect the contribution of different nonlinear ENSO modes to ENSO diversity.

Defining Homogeneous Drought Zones Based on Soil Moisture across Japan and Teleconnections with Large-Scale Climate Signals

2021 ◽  
Author(s):  
Ke Shi ◽  
Yoshiya Touge ◽  
So Kazama
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Large Scale ◽  
Southern Oscillation ◽  
Wavelet Coherence ◽  
The Arctic ◽  
Surface Model ◽  
Drought Prediction ◽  
Climate Signals ◽  
Wavelet Coherence Analysis

Abstract Droughts are widespread disasters worldwide and are concurrently influenced by multiple large-scale climate signals. This is particularly true over Japan, where drought has strong heterogeneity due to multiple factors such as monsoon, topography, and ocean circulations. Regional heterogeneity poses challenges for drought prediction and management. To overcome this difficulty, this study provides a comprehensive analysis of teleconnection between climate signals and homogeneous drought zones over Japan. First, droughts are characterized by simulated soil moisture from land surface model during 1958-2012. The Mclust toolkit, distinct empirical orthogonal function, and wavelet coherence analysis are used, respectively, to investigate the homogeneous drought zone, principal component of each homogeneous zone, and teleconnection between climate signals and drought. Results indicate that nine homogeneous drought zones with different characteristics are defined and quantified. Among these nine zones, zone-1 is dominated by extreme drought events. Zone-2 and zone-6 are typical representatives of spring droughts, while zone-7 is wet for most of the period. The Hokkaido region is divided into wetter zone-4 and drier zone-9. Zone-3, zone-5 and zone-8 are distinguished by the topography. The analyses also reveal almost nine zones have a high level of homogeneity, with more than 60% explained variance. Also, these nine zones are dominated by different large-scale climate signals: the Arctic Oscillation has the strongest impact on zone-1, zone-7, and zone-8; the influence of the North Atlantic Oscillation on zone-3, zone-4, and zone-6 is significant; zone-2 and zone-9 are both dominated by the Pacific Decadal Oscillation; El Niño-Southern Oscillation dominates zone-5. The results will be valuable for drought management and drought prevention.

scholarly journals Análise de dados climáticos usando transformada em ondeletas cruzada e coerência

2020 ◽  
Vol 13 (2) ◽  
pp. 641
Author(s):  
Roseilson Souza Vale ◽  
Raoni Aquino Santana ◽  
Cléo Queresma Dias Júnior
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Wavelet Coherence ◽  
Climate Data ◽  
Mathematical Relationship ◽  
Cross Wavelet Transform ◽  
Climatic Time Series ◽  
Wavelet Coherence Analysis ◽  
Temperature Time ◽  
Cross Wavelet

Este estudo mostra uma análise em transformada em ondeleta cruzada e coerência em ondeleta aplicada a duas séries temporais, sendo uma delas precipitação e a outra temperatura do ar. O objetivo deste estudo é mostrar que esta técnica é uma ferramenta poderosa na análise de séries temporais climáticas, para isso à aplicamos a duas séries com relação física muito conhecida na climatologia. Além da aplicação realizada, recorreu-se também a uma descrição matemática dos métodos. A técnica da transformada em ondeletas cruzada e coerência mostrou-se eficiente em capturar a relação matemática entre as séries de precipitação e temperatura do ar. Com este estudo esperamos difundir o uso desta técnica para fins de ensino e pesquisa em diversos sistemas geofísicos. Analysis of Climate Data Using Transformed Crosswave and Coherence A B S T R A C TThis study presents a cross wavelet transform and wavelet coherence analysis applied to a precipitation and an air temperature time series. The objective of this study is to demonstrate that this technique is a powerful tool in the analysis of climatic time series, and can be applied to two time series with very well-known physical relationships in terms of climatology. In addition to this application, a mathematical description of the methods was done. The cross-curves and coherence technique proved to be efficient in capturing the mathematical relationship between precipitation series and air temperature. With this study we hope to disseminate the use of this technique for teaching and research purposes in various geophysical systems.Keywords: Phase Angle, Wavelet Coherence, Cross wavelet, Precipitation, Temperature. 

scholarly journals Investigating links between rainfall variations in the Ogooué River basin and ENSO in the Pacific Ocean over the period 1940–1999

2021 ◽  
Vol 384 ◽  
pp. 181-186
Author(s):  
Sakaros Bogning ◽  
Frédéric Frappart ◽  
Gil Mahé ◽  
Adrien Paris ◽  
Raphael Onguene ◽  
...  
Keyword(s):  
Time Series ◽  
Pacific Ocean ◽  
River Basin ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
The Pacific ◽  
Basin Scale ◽  
The Pacific Ocean ◽  
Wavelet Coherence Analysis ◽  
Enso Index

Abstract. This paper investigates links between rainfall variability in the Ogooué River Basin (ORB) and El Niño Southern Oscillation (ENSO) in the Pacific Ocean. Recent hydroclimatology studies of the ORB and surrounding areas resulting in contrasting conclusions about links between rainfall variability and ENSO. Thus, to make the issue clearer, this study investigates the links between ENSO and rainfall in the ORB over the period 1940–1999. The principal component analysis of monthly rainfall in the ORB was done. The temporal mode of the first component corresponds to the interannual variations of rainfall on the ORB. Also, the pattern of the spatial mode of the first component shows that the ORB is a homogeneous hydroclimatic zone. However, no leading mode is significantly correlated to the ENSO index. A cross-wavelet analysis of the time series of basin-scale rainfall and the ENSO index was therefore carried out. The result is a set of periodogram structures corresponding to some ENSO episodes recorded over the study period. And wavelet coherence analysis of both time series confirms that there are significant links between ENSO and rainfall in the ORB.

scholarly journals Exploring the "overflow tap" theory: linking forest soil CO<sub>2</sub> fluxes and individual mycorrhizosphere components to photosynthesis

2011 ◽  
Vol 8 (2) ◽  
pp. 3155-3201 ◽  
Author(s):  
A. Heinemeyer ◽  
M. Wilkinson ◽  
R. Vargas ◽  
J.-A. Subke ◽  
E. Casella ◽  
...  
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Wavelet Coherence ◽  
Apparent Temperature ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil System ◽  
Series Analysis ◽  
Environmental Responses ◽  
Wavelet Coherence Analysis

Abstract. Quantifying soil organic carbon stocks and their dynamics accurately is crucial for better predictions of climate change feedbacks within the atmosphere-vegetation-soil system. However, the composition and environmental responses of the soil CO2 efflux (Rs) are still debated and limited by field data. The objective of this study was to quantify the contribution of the various Rs components and to determine their temporal variability, environmental responses and dependence on gross primary productivity (GPP) using time series analysis. In a deciduous oak forest in SE England hourly replicated Rs fluxes over 4 years were obtained using automated soil CO2 flux chambers and ecosystem CO2 exchange using eddy covariance methodology. Mesh-bag and steel collar treatments prevented root or both roots and mycorrhizal hyphal in-growth, respectively, to allow separation of heterotrophic (Rh) and autotrophic (Ra) soil CO2 fluxes and the Ra components, roots (Rr) and mycorrhizal hyphae (Rm). Annual cumulative Rs values were very similar between years (740 ± 43 g C m−2 yr−1) with an average flux of 2.0 ± 0.3 μmol CO2 m−2 s−1, but Rs components varied. On average, annual Rr, Rm and Rh fluxes contributed 39, 18 and 43%, respectively, showing a large Ra contribution (57%) comprising considerable seasonal Rm contributions. Soil temperature largely explained the daily variation of Rs (R2 = 0.81), mostly because of strong responses by Rh (R2 = 0.65) and less so for Rr (R2 = 0.41) and Rm (R2 = 0.18). However, Ra components showed strong apparent temperature responses around budburst and leaf fall but none during summer. Time series analysis revealed strong daily periodicities for Rs, whereas Rr was dominated by daily, Rm by seasonal (~150 days), and Rh by annual periodicities. Wavelet coherence analysis revealed that Rr and Rm were related to short-term (daily) GPP changes, but for R

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