Holocene variations in the Asian monsoon inferred from the geochemistry of lake sediments in central Tibet

Morrill, C.; Overpeck, Jonathan T.; Cole, Julia E.; Liu, Kam Biu; Shen, Caiming; Tang, Lina

doi:10.1016/j.yqres.2005.02.014

Cited by 204 publications

(126 citation statements)

References 46 publications

(67 reference statements)

Supporting

Mentioning

114

Contrasting

Unclassified

Order By: Relevance

“…To avoid subsequent biases, missing data was generally replaced with mean values from the nearest three sites when available; such mean values were also standardized to our five-part scale (e.g. Ahung Co, Morrill et al, 2006;Nam Co, Zhu et al, 2008).…”

Section: Mapping and Ordination Of Palaeomoisture Index Resultsmentioning

confidence: 99%

Asynchronous evolution of the Indian and East Asian Summer Monsoon indicated by Holocene moisture patterns in monsoonal central Asia

Wang

Liu

Herzschuh

2010

Earth-Science Reviews

289

111

View full text Add to dashboard Cite

a b s t r a c t a r t i c l e i n f oThe numerical meta-analysis of 92 proxy records (72 sites) of moisture and/or temperature change confirms earlier findings that the dominant trends of climatic evolution in monsoonal central Asia since the Last Glacial roughly parallel changes in Northern Hemisphere summer insolation, i.e. the period following the Last Glacial Maximum was characterized by dry and cold conditions until 15 cal. kyr BP, followed by a warm, wet period coincident with the Bølling/Allerød warm period and terminated by a cold, dry reversal during the Younger Dryas period. After an abrupt increase at the start of the Holocene, warm and wet conditions prevailed until ca. 4 cal. kyr BP when moisture levels and temperatures started to decrease. Ordination of moisture records reveals strong spatial heterogeneity in moisture evolution during the last 10 cal. kyr. The Indian Summer Monsoon (ISM) areas (northern India, Tibetan Plateau and southwest China) exhibit maximum wet conditions during the early Holocene, while many records from the area of the East Asian Summer Monsoon indicate relatively dry conditions, especially in north-central China where the maximum moisture levels occurred during the mid-Holocene. We assign such phenomena to strengthened Hadley Circulation centered over the Tibetan Plateau during the early Holocene which resulted in subsidence in the East Asian monsoonal regions leading to relatively dry conditions. Our observations of the asynchronous nature of the two Asian monsoon subsystems on millennial time scales have also been observed on annual time-scales as well as implied through the spatial analysis of vertical air motion patterns after strong ascending airflows over the Tibetan Plateau area that were calculated from NCEP/NCAR reanalysis data for the last 30 years. Analogous with the early Holocene, the enhancement of the ISM in a 'future warming world' will result in an increase in the asynchronous nature of the monsoon subsystems; this trend is already observed in the meteorological data from the last 15 years.

show abstract

Section: Mapping and Ordination Of Palaeomoisture Index Resultsmentioning

confidence: 99%

Asynchronous evolution of the Indian and East Asian Summer Monsoon indicated by Holocene moisture patterns in monsoonal central Asia

Wang

Liu

Herzschuh

2010

Earth-Science Reviews

289

111

View full text Add to dashboard Cite

show abstract

“…Holzhauser et al (2005) compared glacier and lake level fluctuations in westcentral Europe over the last 3500 years and demonstrated synchronicity between glacier advances, periods of higher lake levels and maxima of atmospheric radiocarbon. There are numerous other examples of sediment and lake level data that point to a solar link (Baker et al, 2005;Morrill et al, 2006;Patterson et al, 2004;Stager et al, 2005;Verschuren et al, 2000;Wu et al, 2006;Haltia-Hovi et al, 2007).…”

Section: Analysis Of the Componentsmentioning

confidence: 99%

Quantifying and specifying the solar influence on terrestrial surface temperature

Jager

Duhau

Geel

2010

Journal of Atmospheric and Solar-Terrestrial Physics

View full text Add to dashboard Cite

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. b s t r a c tThis investigation is a follow-up of a paper in which we showed that both major magnetic components of the solar dynamo, viz. the toroidal and the poloidal ones, are correlated with average terrestrial surface temperatures. Here, we quantify, improve and specify that result and search for their causes. We studied seven recent temperature files. They were smoothed in order to eliminate the Schwabe-type (11 years) variations. While the total temperature gradient over the period of investigation (1610-1970) is 0.087 1C/century; a gradient of 0.077 1C/century is correlated with the equatorial (toroidal) magnetic field component. Half of it is explained by the increase of the Total Solar Irradiance over the period of investigation, while the other half is due to feedback by evaporated water vapour. A yet unexplained gradient of À 0.040 1C/century is correlated with the polar (poloidal) magnetic field. The residual temperature increase over that period, not correlated with solar variability, is 0.051 1C/century. It is ascribed to climatologic forcings and internal modes of variation.We used these results to study present terrestrial surface warming. By subtracting the above-mentioned components from the observed temperatures we found a residual excess of 0.311 in 1999, this being the triangularly weighted residual over the period 1990-2008. We show that solar forcing of the ground temperature associated with significant feedback is a regularly occurring feature, by describing some well observed events during the Holocene.

show abstract

“…The establishment of modern climate conditions is controversial. Although the general trend to aridity after 4.5 cal ka BP (Gasse et al 1991) can be deduced from several records (Morrill et al 2006;Wu et al 2006b;Wünne-mann et al 2003;Yancheva et al 2007), other lakes such as Boston Lake in the NW (Herzschuh 2006;Wünnemann et al 2006), do not display clear aridity trends. Also, stable isotope records from the Dunde and Guliya ice cores indicate gradual warming, but suggest wet conditions for the late Holocene (Thompson et al 2006;Yao et al 1997).…”

Section: Introductionmentioning

confidence: 98%

“…Investigations focused mainly on sedimentary facies (Morrill et al 2006;Wünnemann et al 2003;Zhai et al 2006), biological proxies Wu et al 2007), pollen Miehe et al 2006), geochemistry (Wu et al 2006b), stable isotopes (Fan et al 2007;Johnson and Ingram 2004;Tian et al 2007) and paleoshoreline features . The broad picture of Holocene climate evolution is consistent and demonstrates that several warm and dry or wet and cold oscillations occurred, but that their timing, duration, and amplitudes differed across the Tibetan Plateau.…”

Section: Introductionmentioning

confidence: 99%

A multi-proxy approach to reconstruct hydrological changes and Holocene climate development of Nam Co, Central Tibet

et al. 2009

View full text Add to dashboard Cite

Holocene lake level fluctuations were reconstructed from a 2.7-m sediment core from Nam Co, Central Tibet, China dating to [7.2 cal ka BP. Results were compared to existing lake records from the Tibetan Plateau to infer variations in the strength of the Asian Monsoon. Geomorphological features in the Nam Co catchment, such as beach ridges and lake terraces, indicate high lake stands during the late Glacial. A major low stand is suggested for the Last Glacial Maximum (LGM). Sands and sandy silts at the base of the core are transgressive facies, with material transported by melt water and deposited under rising lake level conditions that followed the LGM low stand. Variations in grain size, major elements, biomarker stable isotopes and minerals in the core suggest a climate evolution reflected in at least five depositional units and subunits. Sediments in Unit I (*7.2 to *5.4 cal ka BP) were deposited at highest lake levels. Large amounts of allogenic minerals and allochthonous organic matter suggest high precipitation and melt water input, implying positive water balance. Increasing aquatic productivity points to favourable environmental conditions. Unit II (*5.4 to *4.0 cal ka BP) marks a transition between favourable, stable hydrological conditions and lake level decrease. Lower lake levels were a consequence of drier climate with less monsoonal precipitation, higher evaporation rates, and increased moisture recycling in the catchment. Unit III (*4.0 to *1.4 cal ka BP) reflects the driest periods recorded, at *3.7 cal ka BP and 1.6 cal ka BP. Lake shrinkage and salinization was interrupted as suggested by the deposition of Unit IV (*1.4 to *0.8 cal ka BP), when increased precipitation and runoff that might be related to the Medieval Warm Period, led to a stable, but still low lake level. Unit V (800 cal years BPpresent) is characterized by progressive lake shrinkage due to intense evaporation. Paleolimnol (2010) 43:625-648 DOI 10.1007 data indicate the lake level is rising. Comparison of the Nam Co record with other lake records from the Tibetan Plateau suggests general agreement with the broader picture of Holocene environmental evolution. The timing of dry and wet climate conditions at lake sites across Tibet indicates a gradually decreasing influence of the southern monsoon during the Holocene, from NW to SE. Nevertheless, further research is needed to improve our understanding of Holocene spatio-temporal hydrological variations across the Asian continent.

show abstract

Holocene variations in the Asian monsoon inferred from the geochemistry of lake sediments in central Tibet

Cited by 204 publications

References 46 publications

Asynchronous evolution of the Indian and East Asian Summer Monsoon indicated by Holocene moisture patterns in monsoonal central Asia

Asynchronous evolution of the Indian and East Asian Summer Monsoon indicated by Holocene moisture patterns in monsoonal central Asia

Quantifying and specifying the solar influence on terrestrial surface temperature

A multi-proxy approach to reconstruct hydrological changes and Holocene climate development of Nam Co, Central Tibet

Contact Info

Product

Resources

About