Integration of Tibetan Plateau ice-core temperature records and the influence of atmospheric circulation on isotopic signals in the past century

2014 ◽  
Vol 81 (3) ◽  
pp. 520-530 ◽  
Author(s):  
Xiaoxin Yang ◽  
Tandong Yao ◽  
Daniel Joswiak ◽  
Ping Yao
Keyword(s):  
Tibetan Plateau ◽  
Atmospheric Circulation ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Ice Core ◽  
Past Century ◽  
The Tibetan Plateau ◽  
The Past ◽  
Increasing Trends

AbstractTemperature signals in ice-core δ18O on the Tibetan Plateau (TP), particularly in the central and southern parts, continue to be debated because of the large scale of atmospheric circulation. This study presents ten ice-core δ18O records at an annual resolution, with four (Malan, Muztagata, Guliya, and Dunde) in the northern, three (Puruogangri, Geladaindong, Tanggula) in the central and three (Noijin Kangsang, Dasuopu, East Rongbuk) in the southern TP. Integration shows commonly increasing trends in δ18O in the past century, featuring the largest one in the northern, a moderate one in the central and the smallest one in the southern TP, which are all consistent with ground-based measurements of temperature. The influence of atmospheric circulation on isotopic signals in the past century was discussed through the analysis of El Niño/Southern Oscillation (ENSO), and of possible connections between sea surface temperature (SST) and the different increasing trends in both ice-core δ18O and temperature. Particularly, El Niño and the corresponding warm Bay of Bengal (BOB) SST enhance the TP ice-core isotopic enrichment, while La Niña, or corresponding cold BOB SST, causes depletion. This thus suggests a potential for reconstructing the ENSO history from the TP ice-core δ18O.

ENSO modulates the variability of ice core δ18O in the central Tibetan Plateau

2020 ◽  
Author(s):  
Jing Gao ◽  
Tandong Yao ◽  
Guangjian Wu ◽  
Camille Risi
Keyword(s):  
Tibetan Plateau ◽  
El Niño ◽  
Land Surface ◽  
El Nino ◽  
Southern Oscillation ◽  
Ice Core ◽  
The Tibetan Plateau ◽  
Ice Core Record ◽  
Tropical Sea ◽  
Annual Scale

<p>The El Nino-Southern Oscillation (ENSO) drives interannual variability of rainfall, ecosystems and floods in many parts of the world. Climates in the Tibetan Plateau (TP) called as the “water tower” may be impacted by ENSO, but the character of ENSO impact and its mechanism are still not well understood. Here we present the isotopic profiles (δ<sup>18</sup>O) from a new Zangsegangri (ZSGR) ice core drilled in 2013 in the central TP covering 200 years to understand the ENSO impact on the TP climate. The imprint of ENSO is evidenced at annual scale as recorded in ice core. This ice core δ<sup>18</sup>O record also reveal contributions of south/north moisture sources change with the transition of El nino/La nina events which are triggered by the tropical sea surface temperature, associated with the change of convections along the moisture transport paths. These rapid changes lead to the variation of ZSGR ice core δ<sup>18</sup>O, namely El Nino events result in lower δ<sup>18</sup>O in the ZSGR ice core record. The mechanism of ENSO impact on the ZSGR ice core δ<sup>18</sup>O are quantified with LMDZiso model. The significant impact of ENSO activity on the Tibetan ice core record during the past centuries implies the importance of ENSO in land surface processes in the TP.</p>

scholarly journals Reconciling the Discrepancy of Post-Volcanic Cooling Estimated from Tree-Ring Reconstructions and Model Simulations over the Tibetan Plateau

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 738
Author(s):  
Jianping Duan ◽  
Peili Wu ◽  
Zhuguo Ma
Keyword(s):  
Tibetan Plateau ◽  
Climate Variability ◽  
Tree Ring ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Volcanic Eruptions ◽  
The Tibetan Plateau ◽  
Model Simulations ◽  
Internal Climate Variability

Volcanic eruptions are a major factor influencing global climate variability, usually with a cooling effect. The magnitudes of post-volcanic cooling from historical eruptions estimated by tree-ring reconstructions differ considerably with the current climate model simulations. It remains controversial on what is behind such a discrepancy. This study investigates the role of internal climate variability (i.e., El Niño/Southern Oscillation (ENSO) warm phase) with a regional focus on the Tibetan Plateau (TP), using tree-ring density records and long historical climate simulations from the fifth Coupled Model Intercomparsion Project (CMIP5). We found that El Niño plays an important role behind the inconsistencies between model simulations and reconstructions. Without associated El Niño events, model simulations agree well with tree-ring records. Divergence appears when large tropical eruptions are followed by an El Niño event. Model simulations, on average, tend to overestimate post-volcanic cooling during those periods as the occurrence of El Niño is random as part of internal climate variability.

scholarly journals Remote Effects of IOD and ENSO on Motivating the Atmospheric Pattern Favorable for Snowfall Over the Tibetan Plateau in Early Winter

2021 ◽  
Vol 3 ◽  
Author(s):  
Hongyan Shen ◽  
Zhiqiang Gong ◽  
Boqi Liu ◽  
Yipeng Guo ◽  
Xiaoli Feng ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Thermal Conditions ◽  
The Tibetan Plateau ◽  
Early Winter ◽  
Atmospheric Conditions ◽  
Leading Role ◽  
Community Atmosphere Model

The interannual variation of snowfall over the Tibetan Plateau (TP) in early winter (November–December) and its related atmospheric attribution are clarified. Meanwhile, the influence of tropical sea surface temperatures (SSTs) on TP snowfall is investigated by diagnostic analyses and Community Atmosphere Model (CAM5) simulations. The leading mode of TP snowfall in early winter features a spatially uniform pattern with remarkable interannual variability. It is found that the Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO) are main external forcing factors for TP snowfall. Positive IOD with positive ENSO and positive IOD with neutral ENSO cases both have remote impact on motivating Southern Eurasia (SEA) pattern, which can induce an anomalous cyclone around the TP. The corresponding anomalous ascending motion and cold air in the mid-upper troposphere provide the dynamical and thermal conditions for heavy snowfall. The low-level southwesterly winds are enhanced over the Arabian Sea and Bay of Bengal, bringing abundant water vapor into the TP for excessive snowfall. Furthermore, CAM5 simulation experiments forced by IOD- and ENSO-related SST anomalies are performed to verify their combined and independent effects on TP snowfall in early winter. It is confirmed that either positive IOD or El Niño has certain impacts on motivating circulation anomalies favorable for snowfall over the TP. However, IOD plays a leading role in producing the excessive snowfall-related atmospheric conditions, and there is an asymmetric influence of ENSO and IOD on the TP snowfall.

scholarly journals Impact of developing ENSO on the Tibetan Plateau summer rainfall

2021 ◽  
pp. 1-56
Author(s):  
Shuai Hu ◽  
Tianjun Zhou ◽  
Bo Wu
Keyword(s):  
Tibetan Plateau ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Summer Rainfall ◽  
Climate Impacts ◽  
South Asian High ◽  
The Tibetan Plateau ◽  
Research Attention

AbstractThe year-to-year variations of Tibetan Plateau (TP) summer rainfall have tremendous climate impacts on the adjoining and even global climate, attracting extensive research attention in recent decades to understand the underlying mechanism. In this study, we investigate an open question of how the El Niño-Southern Oscillation (ENSO) influences the TP precipitation. We show that the developing ENSO has significant impacts on the summer rainfall over the southwestern TP (SWTP), which is the second EOF mode of the interannual variability of summer rainfall over the TP. Moisture budget indicates that both the suppressed vertical motion and the deficit of moisture contribute to the reduction of SWTP rainfall during El Niño’s developing summer, with the former contribution four times larger than the latter. Moist static energy analyses indicate that the anomalous advection of climatological moist enthalpy by anomalous zonal wind is responsible for the anomalous descending motions over the SWTP. The El Niño-related southward displacements of the South Asian high and the upper-level cyclonic anomalies over the west of TP stimulated by the suppressed Indian summer monsoon precipitation are two key processes dominating the anomalous zonal moist enthalpy advection over SWTP. Meanwhile, the India-Burma monsoon trough is strengthened during El Niño developing summer, which prevents the water vapor into the SWTP, and thus contributes to the deficit of summer SWTP rainfall. Our results help to understand the complicated ENSO-related air-sea interaction responsible for the variability of TP precipitation and have implications for seasonal prediction of the TP climate.

Summer Cooling Driven by Large Volcanic Eruptions over the Tibetan Plateau

2018 ◽  
Vol 31 (24) ◽  
pp. 9869-9879 ◽  
Author(s):  
Jianping Duan ◽  
Lun Li ◽  
Zhuguo Ma ◽  
Jan Esper ◽  
Ulf Büntgen ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
El Niño ◽  
El Nino ◽  
Volcanic Eruptions ◽  
The Tibetan Plateau ◽  
Temperature Deviation ◽  
El Niño Event ◽  
El Niño Events ◽  
Large Volcanic Eruptions ◽  
El Nino Events

Large volcanic eruptions may cause abrupt summer cooling over large parts of the globe. However, no comparable imprint has been found on the Tibetan Plateau (TP). Here, we introduce a 400-yr-long temperature-sensitive network of 17 tree-ring maximum latewood density sites from the TP that demonstrates that the effects of tropical eruptions on the TP are generally greater than those of extratropical eruptions. Moreover, we found that large tropical eruptions accompanied by subsequent El Niño events caused less summer cooling than those that occurred without El Niño association. Superposed epoch analysis (SEA) based on 27 events, including 14 tropical eruptions and 13 extratropical eruptions, shows that the summer cooling driven by extratropical eruptions is insignificant on the TP, while significant summer temperature decreases occur subsequent to tropical eruptions. Further analysis of the TP August–September temperature responses reveals a significant postvolcanic cooling only when no El Niño event occurred. However, there is no such cooling for all other situations, that is, tropical eruptions together with a subsequent El Niño event, as well as extratropical eruptions regardless of the occurrence of an El Niño event. The averaged August–September temperature deviation ( Tdev) following 10 large tropical eruptions without a subsequent El Niño event is up to −0.48° ± 0.19°C (with respect to the preceding 5-yr mean), whereas the temperature deviation following 4 large tropical eruptions with an El Niño association is approximately 0.23° ± 0.16°C. These results indicate a mitigation effect of El Niño events on the TP temperature response to large tropical eruptions. The possible mechanism is that El Niño events can weaken the Indian summer monsoon with a subsequent decrease in rainfall and cooling effect, which may lead to a relatively high temperature on the TP, one of the regions affected by the Indian summer monsoon.

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.

Monitoring Agricultural Drought Using El Niño and Southern Oscillation Data

2005 ◽  
Author(s):  
Lino Naranjo Díaz
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Climatic Variability ◽  
Past Century ◽  
Climatic Data ◽  
Weather Patterns ◽  
El Niño Events ◽  
Ring Analysis ◽  
El Nino Events

Almost all the studies performed during the past century have shown that drought is not the result of a single cause. Instead, it is the result of many factors varying in nature and scales. For this reason, researchers have been focusing their studies on the components of the climate system to explain a link between patterns (regional and global) of climatic variability and drought. Some drought patterns tend to recur frequently, particularly in the tropics. One such pattern is the El Niño and Southern Oscillation (ENSO). This chapter explains the main characteristics of the ENSO and its data forms, and how this phenomenon is related to the occurrence of drought in the world regions. Originally, the name El Niño was coined in the late 1800s by fishermen along the coast of Peru to refer to a seasonal invasion of south-flowing warm currents of the ocean that displaced the north-flowing cold currents in which they normally fished. The invasion of warm water disrupts both the marine food chain and the economies of coastal communities that are based on fishing and related industries. Because the phenomenon peaks around the Christmas season, the fishermen who first observed it named it “El Niño” (“the Christ Child”). In recent decades, scientists have recognized that El Niño is linked with other shifts in global weather patterns (Bjerknes, 1969; Wyrtki, 1975; Alexander, 1992; Trenberth, 1995; Nicholson and Kim, 1997). The recurring period of El Niño varies from two to seven years. The intensity and duration of the event vary too and are hard to predict. Typically, the duration of El Niño ranges from 14 to 22 months, but it can also be much longer or shorter. El Niño often begins early in the year and peaks in the following boreal winter. Although most El Niño events have many features in common, no two events are exactly the same. The presence of El Niño events during historical periods can be detected using climatic data interpreted from the tree ring analysis, sediment or ice cores, coral reef samples, and even historical accounts from early settlers.

scholarly journals Extended ENSO Predictions Using a Fully Coupled Ocean–Atmosphere Model

2008 ◽  
Vol 21 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Jing-Jia Luo ◽  
Sebastien Masson ◽  
Swadhin K. Behera ◽  
Toshio Yamagata
Keyword(s):  
El Niño ◽  
General Circulation ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Ocean ◽  
Enso Events ◽  
The Past ◽  
Ocean Atmosphere ◽  
First Time ◽  
Fully Coupled

Abstract Using a fully coupled global ocean–atmosphere general circulation model assimilating only sea surface temperature, the authors found for the first time that several El Niño–Southern Oscillation (ENSO) events over the past two decades can be predicted at lead times of up to 2 yr. The El Niño condition in the 1997/98 winter can be predicted to some extent up to about a 1½-yr lead but with a weak intensity and large phase delay in the prediction of the onset of this exceptionally strong event. This is attributed to the influence of active and intensive stochastic westerly wind bursts during late 1996 to mid-1997, which are generally unpredictable at seasonal time scales. The cold signals in the 1984/85 and 1999/2000 winters during the peak phases of the past two long-lasting La Niña events are predicted well up to a 2-yr lead. Amazingly, the mild El Niño–like event of 2002/03 is also predicted well up to a 2-yr lead, suggesting a link between the prolonged El Niño and the tropical Pacific decadal variability. Seasonal climate anomalies over vast parts of the globe during specific ENSO years are also realistically predicted up to a 2-yr lead for the first time.

scholarly journals Temperature variations over the past millennium on the Tibetan Plateau revealed by four ice cores

2007 ◽  
Vol 46 ◽  
pp. 362-366 ◽  
Author(s):  
Tandong Yao ◽  
Keqin Duan ◽  
L.G. Thompson ◽  
Ninglian Wang ◽  
Lide Tian ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
19Th Century ◽  
Northern Hemisphere ◽  
Ice Core ◽  
Ice Cores ◽  
Ice Age ◽  
The Tibetan Plateau ◽  
Late 19Th Century ◽  
The Past ◽  
Northern Tibetan Plateau

AbstractTemperature variation on the Tibetan Plateau over the last 1000 years has been inferred using a composite δ18O record from four ice cores. Data from a new ice core recovered from the Puruogangri ice field in the central Tibetan Plateau are combined with those from three other cores (Dunde, Guliya and Dasuopu) recovered previously. The ice-core δ18O composite record indicates that the temperature change on the whole Tibetan Plateau is similar to that in the Northern Hemisphere on multi-decadal timescales except that there is no decreasing trend from AD 1000 to the late 19th century. The δ18O composite record from the northern Tibetan Plateau, however, indicates a cooling trend from AD 1000 to the late 19th century, which is more consistent with the Northern Hemisphere temperature reconstruction. The δ18O composite record reveals the existence of the Medieval Warm Period and the Little Ice Age (LIA) on the Tibetan Plateau. However, on the Tibetan Plateau the LIA is not the coldest period during the last millennium as in other regions in the Northern Hemisphere. The present study indicates that the 20th-century warming on the Tibetan Plateau is abrupt, and is warmer than at any time during the past 1000 years.

scholarly journals Effects of large scale dynamic phenomena of the summer atmospheric circulation over the Aegean basin

2020 ◽  
Author(s):  
Ιωάννης Λογοθέτης
Keyword(s):  
Atmospheric Circulation ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Representative Concentration Pathways ◽  
Historical Scenario ◽  
Dynamic Phenomena

Η παρούσα διδακτορική διατριβή στοχεύει στη μελέτη των επιδράσεων δυναμικών φαινομένων μεγάλης κλίμακας στην ατμοσφαιρική κυκλοφορία της ανατολικής Μεσογείου εστιάζοντας στη λεκάνη του Αιγαίου κατά τη θερινή περίοδο (Μάιος - Σεπτέμβριος). Στο πλαίσιο της παρούσας έρευνας γίνεται μελέτη φαινομένων τηλεσύνδεσης που επιδρούν στην ατμοσφαιρική κυκλοφορία της ανατολικής Μεσογείου. Η ανάλυση γίνεται με δεδομένα από προσομοιώσεις Μοντέλων Γήινου Συστήματος (ESMs) που είναι διαθέσιμα στο πλαίσιο της πέμπτης φάσης του προγράμματος Σύγκρισης Συζευγμένων Μοντέλων (CMIP5), το οποίο δρα υποστηρικτικά για το Πόρισμα της Διακυβερνητικής Επιτροπής για τις Κλιματικές Αλλαγές (IPCC, AR5). Στο πλαίσιο του Πορίσματος του IPCC έχει αναπτυχθεί σειρά σεναρίων τα οποία χρησιμοποιούνται για την μελέτη του κλίματος. Η μελέτη εστιάζεται: (α) στην ιστορική περίοδο (historical scenario simulatiuons) για το παρόν-παρελθόν (1900-2005) και (β) προσομοιώσεις των Αντιπροσωπευτικών Συγκεντρώσεων (Representative Concentration Pathways, RCPc) για το μέλλον (2006-2100). Επίσης γίνεται χρήση δεδομένων επανανάλυσης (reanlysis data) από το Ευρωπαϊκό Κέντρο Μεσοπρόθεσμων Μετεωρολογικών Προγνώσεων (ECMWF) για το παρόν (ERA-Interim) και το παρελθόν (ERA20C), καθώς και δεδομένων παρατηρήσεων (observations) ανάλογα με τη διαθεσιμότητα. Στόχοι της διατριβής είναι η συμβολή στην κατανόηση της ατμοσφαιρικής κυκλοφορίας στην ανατολική Μεσόγειο, του φαινομένου των Ετησιών ανέμων και της τηλεσύνδεσης της Νότιας Κύμανσης (El- Niño Southern Oscillation; ENSO) με τον Ινδικό καλοκαιρινό Μουσώνα και την κυκλοφορία της ανατολικής Μεσογείου. Τα αποτελέσματα της διδακτορικής διατριβής έδειξαν ότι οι Ετησίες στην κατώτερη και η καθοδική κυκλοφορία στην μέση τροπόσφαιρα είναι τα κύρια χαρακτηριστικά της θερινής ατμοσφαιρικής κυκλοφορία στην ανατολική Μεσόγειο. Στην περιοχή του Ινδικού μουσώνα το κύριο χαρακτηριστικό της κυκλοφορίας είναι οι ανοδικές κινήσεις με την μέγιστη ένταση να εντοπίζεται στο τμήμα του δυτικού Ινδικού καλοκαιρινού Μουσώνα και στον κόλπο της Βεγγάλης. Οι ανοδικές κινήσεις πάνω από τον Ινδικό Μουσώνα, η καθοδική κυκλοφορία στην ανατολική Μεσόγειο και οι Ετησίες άνεμοι παρουσιάζουν ταυτόχρονα μέγιστο την περίοδο Ιουλίου-Αυγούστου. Στην περιοχή της ανατολικής Μεσογείου η βαθμίδα της πίεσης που δημιουργείται από την διαφορά των πιέσεων μεταξύ ενός κέντρου υψηλών πιέσεων στα βόρεια Βαλκάνια και ενός χαμηλού στην νοτιοανατολική Μεσόγειο είναι υπεύθυνη για την πνοή του συστήματος των Ετησιών ανέμων κατά την θερινή περίοδο στο Αιγαίο. Η ανάλυση έδειξε ότι τα μοντέλα είναι ικανά να προσομοιώσουν την εποχική εξέλιξη και συχνότητα των Ετησιών αν και υποεκτιμούν την ταχύτητα του ανέμου. Επιπλέον, η μελέτη επιβεβαιώνει την επίδραση του Ινδικού Μουσώνα στην κατώτερη, μέση και ανώτερη τροποσφαιρική κυκλοφορία της ανατολικής Μεσογείου. Επιπρόσθετα, η ανάλυση έδειξε την επίδραση του ENSO στον Ινδικό καλοκαιρινό Μουσώνα και στο κέντρο χαμηλών πιέσεων που εντοπίζεται στην νότιοανατολική Μεσόγειο ως τμήμα της επέκτασης ενός θερμικού χαμηλού που εκτείνεται από τον δυτικό Ινδικό μουσώνα μέχρι την νοτιοανατολική Μεσόγειο κατά τους καλοκαιρινούς μήνες. Οι εκτιμήσεις για την τελευταία περίοδο του εικοστού πρώτου αιώνα (2070-2100), με βάση το ακραίο σενάριο (RCP8.5), έδειξαν εξασθένηση της κυκλοφορίας μεγάλης κλίμακας και ενίσχυση της βροχόπτωσης στην περιοχή του Ινδικού Μουσώνα. Όπως στο παρελθόν έτσι και στο μέλλον η βαθμίδα της πίεσης στο Αιγαίο φαίνεται πως οδηγεί στην πνοή των Ετησιών ανέμων. Τέλος, η ανάλυση δεν έδειξε ξεκάθαρες μεταβολές για το σύστημα των Ετησιών.

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