Moisture evolution in North Xinjiang (northwest China) during the last 8000 years linked to the westerlies’ winter half-year precipitation

2020 ◽  
pp. 1-13
Author(s):  
Xiaonan Zhang ◽  
Aifeng Zhou ◽  
Zhendong Huang ◽  
Chengbang An ◽  
Yongtao Zhao ◽  
...  
Keyword(s):  
Grain Size ◽  
Lake Level ◽  
Latitudinal Gradient ◽  
Northwest China ◽  
Winter Precipitation ◽  
Boreal Winter ◽  
The Holocene ◽  
Winter Half ◽  
North Xinjiang ◽  
Winter Insolation

Abstract Winter half-year precipitation dominates variations in hydroclimatic conditions in North Xinjiang, but few researchers have focused on this very important aspect of the Holocene climate. Here we report multiproxy evidence of Holocene hydroclimate changes from the sediments of Wulungu Lake in North Xinjiang. The site is a closed terminal lake fed mainly by meltwater from snow and ice, and today the area is climatically dominated by the westerlies. Grain-size end-member analysis implies an important mode of variation that indicates a gradually increasing moisture trend, with superimposed centennial-scale variations, since 8000 cal yr BP. From 8000 to 5350 cal yr BP, a permanent lake developed, and the lake level gradually rose. Between 5350 and 500 cal yr BP, the moisture status increased rapidly, with the wettest climate occurring between 3200 and 500 cal yr BP. After 500 cal yr BP, the lake level fell. The trend of increasing Holocene wetness indicates a rising winter precipitation in North Xinjiang during the Holocene. This was due to an increase in upwind vapor concentrations caused by increased evaporation and strength of the westerlies, which were determined by the increasing boreal winter insolation and its latitudinal gradient.

Sedimentary grain-size record of Holocene runoff fluctuations in the Lake Lugu watershed, SE Tibetan Plateau

The Holocene ◽  
2020 ◽  
pp. 095968362097277
Author(s):  
Xiaonan Zhang ◽  
Hucai Zhang ◽  
Fengqin Chang ◽  
Umar Ashraf ◽  
Han Wu ◽  
...  
Keyword(s):  
Grain Size ◽  
Tibetan Plateau ◽  
Lake Level ◽  
Boreal Summer ◽  
Lake Basin ◽  
Lake Surface ◽  
The Holocene ◽  
Tropical Ssts ◽  
Moisture Conditions ◽  
Lake Lugu

Changes in moisture conditions or precipitation in the SE Tibetan Plateau during the Holocene have been studied using various environmental archives and proxies. However, due to different interpretations of the proxies and records, the pattern of Holocene precipitation/moisture variations in the region remains unclear. A lake-sediment-based reconstruction of runoff variations, which can directly and sensitively reflect changes in precipitation, provides the opportunity to reconstruct the evolution of moisture conditions in the SE Tibetan Plateau during the Holocene. In this study, we used a well-dated sediment core (LGH2) from Lake Lugu, a deep alpine lake charged mainly by precipitation on the lake surface and by runoff from the watershed, to reconstruct variations in runoff during the Holocene. In addition, 70 lake surface sediment samples were collected to examine the spatial variation of grain size. Endmember modeling analysis of the grain-size data was used to characterize the processes of sediment transport and runoff fluctuations. The carbonate content of core LGH2 shows that the lake level was generally high during 11,600–3100 cal years BP, and that the lake basin was closed after 3100 cal years BP and semi-closed since 90 cal years BP. Grain-size endmember EM 3, which represents the runoff input clastic materials, is used to reconstruct runoff fluctuations in the Lake Lugu watershed. The record indicates a gradual increase in runoff during 11,600–9000 cal years BP, stable and high runoff during 9000–2000 cal years BP, and weak runoff and a low lake level since 2000 cal years BP. Our reconstruction of runoff fluctuations tracks changes in regional temperature and tropical SSTs rather than in boreal summer insolation. This finding supports the hypothesis that increasing tropical SSTs strengthened ITCZ convection which enhanced the flux of water vapour from the ocean to the air, and hence the moisture supplies to SW China.

Partitioning of the grain-size components of Dali Lake core sediments: evidence for lake-level changes during the Holocene

2008 ◽  
Vol 42 (2) ◽  
pp. 249-260 ◽  
Author(s):  
Jule Xiao ◽  
Zhigang Chang ◽  
Bin Si ◽  
Xiaoguang Qin ◽  
Shigeru Itoh ◽  
...  
Keyword(s):  
Grain Size ◽  
Lake Level ◽  
Core Sediments ◽  
The Holocene ◽  
Lake Level Changes ◽  
Dali Lake ◽  
Lake Core

Holocene sedimentation in the Hupo Trough of the southwestern East Sea (Japan Sea) and development of the East Korea Warm Current

The Holocene ◽  
2021 ◽  
pp. 095968362110032
Author(s):  
Boo-Keun Khim ◽  
Sunghan Kim ◽  
Yu-Hyeon Park ◽  
Jongmin Lee ◽  
Sangbeom Ha ◽  
...  
Keyword(s):  
Grain Size ◽  
Japan Sea ◽  
East Sea ◽  
Eastern Coast ◽  
Size Change ◽  
Sediment Properties ◽  
Warm Current ◽  
The Holocene ◽  
Mean Grain Size ◽  
East Korea Warm Current

Various sediment properties, such as mean grain size, total organic carbon, total nitrogen, C/N ratio, CaCO3, and biogenic opal content, were analyzed for a box core (BC02; 45 cm long) and a gravity core (GC02; 628 cm long), which were collected from the western margin of the Hupo Trough located off the eastern coast of Korea. The study area has been affected by the East Korea Warm Current (EKWC), a branch of the Tsushima Warm Current (TWC). The analytical results obtained for BC02 and the upper part of GC02 were in agreement, affirming the core-top preservation of GC02. Based on the corrected calibrated AMS 14C dates, the sedimentation rate of GC02 changed abruptly at ~8.2 ka from ~4.0–10.2 cm/kyr in the lower part to ~56.6–91.0 cm/kyr in the middle to upper part. This corresponds to the lithologic change from sandy mud to mud sediments showing the mean grain size change from 6.9 to 46.0 μm. Diverse paleoceanographic proxies representing the surface water condition exhibited varying degree of change at ~8.2 ka, after which all the properties remain almost unchanged, implying stable and continuous depositional conditions following the complete development of the EKWC. Furthermore, it indicated that the sediment depositional conditions in the Hupo Trough in response to the EKWC might have stabilized at ~8.2 ka since the opening of the Korea Strait during the Holocene sea level rise. Moreover, microfossil data from previous studies on the establishment of the TWC in the East Sea (Japan Sea) support our interpretation that the sediment properties revealed the Holocene development of the EKWC in the Hupo Trough.

scholarly journals Variations in Lake Levels during the Holocene in North America: An Indicator of Changes in Atmospheric Circulation Patterns

2007 ◽  
Vol 39 (2) ◽  
pp. 141-150 ◽  
Author(s):  
S. P. Harrison ◽  
S. E. Metcalfe
Keyword(s):  
North America ◽  
General Circulation ◽  
Lake Level ◽  
Data Bank ◽  
Relative Depth ◽  
Lake Levels ◽  
Regional Patterns ◽  
Air Mass ◽  
The Holocene ◽  
Lake Status

ABSTRACT Fluctuations in the extent of closed lakes provide a detailed record of regional and continental variations in mean annual water budget. The temporal sequence of hydrological fluctuations during the Holocene in North America has been reconstructed using information from the Oxford Lake-Level Data Bank. This data base includes 67 basins from the Americas north of the equator. Maps of lake status, an index of relative depth, are presented for the period 10,000 to 0 yr BP. The early Holocene was characterised by increasingly arid conditions, which led to widespread low lake levels in the mid-latitudes by 9,000 yr BP. By 6,000 yr BP this zone of low lakes extended from 32o to 51oN. Many of the features of the present day lake-level pattern, particularly high lake levels north of 46oN and along the eastern seaboard, were established by 3.000 yr BP. Four distinctive regional patterns of lake behaviour through time are apparent. Histograms of lake status from 20,000 to 0 yr BP are presented for each of these regions. They illustrate the temporal patterns of lake-level fluctuations on a time scale of 103 — 104 yr. Changes in lake status over North America are interpreted as indicating displacements in major features of the general circulation, specifically the zonal Westerlies and the Equatorial Trough, as reflected by changes in air mass trajectories and hence the position of air mass boundaries over the continent.

scholarly journals A major hydrobiological change in Dasht-e Arjan Wetland (southwestern Iran) during the late glacial – early Holocene transition revealed by subfossil chironomids

2019 ◽  
Vol 56 (8) ◽  
pp. 848-856
Author(s):  
Cyril Aubert ◽  
Morteza Djamali ◽  
Matthew Jones ◽  
Hamid Lahijani ◽  
Nick Marriner ◽  
...  
Keyword(s):  
Lake Level ◽  
Regional Scale ◽  
Younger Dryas ◽  
Late Glacial ◽  
Early Holocene ◽  
Geochemical Data ◽  
The Holocene ◽  
Chironomus Plumosus ◽  
Subfossil Chironomids ◽  
Southwestern Iran

The late glacial – early Holocene transition is a key period in the earth’s history. However, although this transition is well studied in Europe, it is not well constrained in the Middle East and palaeohydrological records with robust chronologies remain scarce from this region. Here we present an interesting hydrobiological record showing a major environmental change occurring in the Dasht-e Arjan Wetland (southwestern Iran, near to Persepolis) during the late glacial – early Holocene transition (ca. 11 650 years cal BP). We use subfossil chironomids (Insecta: Diptera) as a proxy for hydrological changes and to reconstruct lake-level fluctuations. The Arjan wetland was a deep lake during the Younger Dryas marked by a dominance of Chironomus plumosus/anthracinus-type, taxa adapted to anoxic conditions of deep waters. At the beginning of the Holocene, a drastic decrease (more than 80% to less than 10%) of Chironomus plumosus/anthracinus-type, combined with diversification of littoral taxa such as Polypedilum nubeculosum-type, Dicrotendipes nervosus-type, and Glyptotendipes pallens-type, suggests a lake-level decrease and a more vegetalized aquatic environment. We compare and contrast the chironomid record of Arjan with a similar record from northwestern Iran. The palaeoclimatic significance of the record, at a local and regional scale, is subsequently discussed. The increase in Northern Hemisphere temperatures, inferred by geochemical data from NGRIP, at the beginning of the Holocene best explains the change from the Younger Dryas highstand to early Holocene lowstand conditions in the Dasht-e Arjan wetland. However, a contribution of the meltwater inflow from small local glaciers in the catchment basin is not excluded.

Spatial heterogeneity of surface sediment grain size and aeolian activity in the gobi desert region of northwest China

CATENA ◽  
2020 ◽  
Vol 188 ◽  
pp. 104469 ◽  
Author(s):  
Yaping Shen ◽  
Chunlai Zhang ◽  
Rende Wang ◽  
Xuesong Wang ◽  
Songbo Cen ◽  
...  
Keyword(s):  
Grain Size ◽  
Spatial Heterogeneity ◽  
Surface Sediment ◽  
Northwest China ◽  
Gobi Desert ◽  
Sediment Grain Size ◽  
Desert Region ◽  
Aeolian Activity

High-resolution boreal winter precipitation projections over tropical America from CMIP5 models

2017 ◽  
Vol 51 (5-6) ◽  
pp. 1773-1792 ◽  
Author(s):  
Reiner Palomino-Lemus ◽  
Samir Córdoba-Machado ◽  
Sonia Raquel Gámiz-Fortis ◽  
Yolanda Castro-Díez ◽  
María Jesús Esteban-Parra
Keyword(s):  
High Resolution ◽  
Winter Precipitation ◽  
Cmip5 Models ◽  
Boreal Winter ◽  
Tropical America ◽  
Precipitation Projections

Charophyte Population Dynamics during the Late Quaternary at Lake Bibersee, Switzerland

1999 ◽  
Vol 47 (3) ◽  
pp. 315 ◽  
Author(s):  
Jean Nicolas Haas
Keyword(s):  
Bronze Age ◽  
Lake Level ◽  
Climatic Factors ◽  
Late Quaternary ◽  
Prehistoric Agriculture ◽  
The Holocene ◽  
Ph Values ◽  
Middle Bronze Age ◽  
The Town ◽  
Boreal Period

Oospores of 11 charophyte species were found in the Late Quaternary gyttja deposits of Lake Bibersee near the town of Zug. Except for the Boreal period rarely more than three different species were growing simultaneously during the Holocene. This compares well to typical Characeae lakes of the same size today, and shows that considerable changes in the hydrophyte diversity have taken place through time. During the first part of the Holocene the lake was oligotrophic and the species composition was mainly regulated by lake-level fluctuations due to climatic factors. During the younger periods of the Holocene the lake became mesotrophic, and pH values were for a longer period slightly alkaline. During the Early to Middle Bronze Age (1900–1400 BC) the considerable alterations in the hydrophyte composition and the simultaneous extensive prehistoric agriculture on the fertile shores of the lake point to human impact as the primary cause for changes in charophyte diversity.

Sign in / Sign up

Export Citation Format

Share Document