scholarly journals Humid and cold periods in the last 5600 years in Arid Central Asia revealed by palynology of Picea schrenkiana from Issyk-Kul

The Holocene ◽  
2020 ◽  
pp. 095968362097277
Author(s):  
Suzanne AG Leroy ◽  
Santiago R Giralt
Keyword(s):  
Central Asia ◽  
Bronze Age ◽  
Tien Shan ◽  
Ice Age ◽  
Forest Belt ◽  
Pollen Record ◽  
Picea Schrenkiana ◽  
Arid Central Asia ◽  
Mountain Glaciers ◽  
Ancient Silk Road

Central Asia, with its high mountains, despite its location between Europe and eastern Asia remains a data poor area. However, mountain glaciers are strongly affected by global change and have a wide-ranging impact. A new pollen record over the last 5600 years shows the extension of a dry Artemisia steppe around Lake Issyk-Kul, with a slightly wetter period from 4.5 to 2.7 ka BP (less Ephedra). Picea schrenkiana forest growing on north-facing slopes of the northern Tien Shan Range, are exposed to Westerlies-related precipitation. The pollen record of Picea is therefore a very good marker of wetter and cold conditions. A comparison to a nearby synchronous pollen record at a higher altitude indicates that the whole forest belt moved down, and that it was not a downwards extension of the lower forest limit only. Four cold and humid phases were evidenced over the last 5.6 ka: 5.5 ka, 4.2 ka and following centuries, 3.2 ka and following centuries (before the end of the Bronze Age) and finally the Little Ice Age, with the latter two being more strongly expressed. These climatic changes, in agreement with other Arid Central Asia investigations, corroborate the driving role of the Westerlies far inland. Human activities were more intense in the Mid and Late Bronze Age (4.5–3.2 ka) and in the last 800 years, confirmed by archaeological and historical information. Issyk-Kul and surrounding rich pastureland were most likely an important step in the ancient Silk Road.

Abrupt Freshening Since the Early Little Ice Age in Lake Sayram of Arid Central Asia Inferred From an Alkenone Isomer Proxy

2020 ◽  
Vol 47 (16) ◽  
Author(s):  
Yuan Yao ◽  
Jianghu Lan ◽  
Jiaju Zhao ◽  
Richard S. Vachula ◽  
Hai Xu ◽  
...  
Keyword(s):  
Central Asia ◽  
Little Ice Age ◽  
Ice Age ◽  
Arid Central Asia

scholarly journals Relation between recent glacier variations and climate in the Tien Shan mountains, central Asia

1992 ◽  
Vol 16 ◽  
pp. 11-16 ◽  
Author(s):  
Liu Chaohai ◽  
Han Tianding
Keyword(s):  
Mass Balance ◽  
Central Asia ◽  
Air Temperature ◽  
Little Ice Age ◽  
General Trend ◽  
Summer Temperature ◽  
Tien Shan ◽  
Ice Age ◽  
Climatic Fluctuations ◽  
Tien Shan Mountains

Since the Little Ice Age, most glaciers in the Tien Shan mountains have been retreating. Owing to an increase in precipitation in most parts of the mountains during the late 1950s to early 1970s, the percentage of receding glaciers and the speed of retreat have tended to decrease in the 1970s. However, the general trend of continuous glacier retreat remains unchanged, in part because the summer air temperature shows no tendency to decrease.In the Tien Shan mountains, as the degree of climatic continentality increases the mass balance becomes more dependent on summer temperature, and accumulation and ablation tend to be lower. Therefore, the responses of glaciers to climatic fluctuations in more continental areas are not synchronous with those in less continental areas, and the amplitude of the glacier variations becomes smaller.

Ice thickness, volume and subglacial relief of Ashuu-Tor, Bordu, Kara-Batkak and Golubina glaciers (Central-Asia) derived from GPR measurements and different approaching methods

2020 ◽  
Author(s):  
Lander Van Tricht ◽  
Philippe Huybrechts ◽  
Jonas Van Breedam ◽  
Johannes Fuerst ◽  
Oleg Rybak ◽  
...  
Keyword(s):  
Central Asia ◽  
Thickness Distribution ◽  
Mass Conservation ◽  
Tien Shan ◽  
Ice Age ◽  
Ice Thickness ◽  
Mountain Range ◽  
Lake Formation ◽  
Ground Penetrating ◽  
Thickness Measurements

<p>Glaciers in the Tien Shan (Central-Asia) mountains contribute a considerable part of the freshwater used for irrigation and households in the dry lowland areas of Kyrgyzstan and its neighbouring countries. Since the Little Ice Age, the total ice mass in this mountain range has been decreasing significantly. However, accurate measurements of the current ice volume and ice thickness distribution in the Tien Shan remain scarce, and accurate data is largely lacking at the local scale. In 2016, 2017 and 2019, we organized 1-month field campaigns in Central-Asia to sound the ice thickness of four different glaciers in the Tien Shan using a Narod ground penetrating radar (GPR) system.</p><p>Here, we present and discuss our in-situ ice thickness measurements of the four glaciers. We performed in total more than 1000 GPR soundings. We found a maximum ice thickness of 200 meters in the central part of the southern facing Ashuu-Tor glacier. On both Bordu and Golubina, we measured ice thicknesses up to 140 meters. Kara-Batkak was found to have the thinnest ice which is in agreement to the large average slope of this glacier. We extended all the ice thickness measurements to the entire glacier surfaces using three different methods based on the assumption of plastic flow (method 1) and the principle of mass conservation (method 2 & 3) and assessed their differences.</p><p>In this research, we show a detailed ice thickness distribution of Ashuu-Tor, Bordu, Golubina and Kara-Batkak glaciers. This can be used for glaciological modelling and assessing ice and water storage. We also point out the locations of potential lake formation in bedrock overdeepenings as a succession of glacier retreat.</p>

scholarly journals High-resolution leaf wax carbon and hydrogen isotopic record of the late Holocene paleoclimate in arid Central Asia

2015 ◽  
Vol 11 (4) ◽  
pp. 619-633 ◽  
Author(s):  
B. Aichner ◽  
S. J. Feakins ◽  
J. E. Lee ◽  
U. Herzschuh ◽  
X. Liu
Keyword(s):  
Central Asia ◽  
Late Holocene ◽  
Large Scale ◽  
Climate Model ◽  
Precipitation Amount ◽  
Ice Age ◽  
Late Winter ◽  
Arid Central Asia ◽  
Leaf Wax ◽  
D Values

Abstract. Central Asia is located at the confluence of large-scale atmospheric circulation systems. It is thus likely to be highly susceptible to changes in the dynamics of those systems; however, little is still known about the regional paleoclimate history. Here we present carbon and hydrogen isotopic compositions of n-alkanoic acids from a late Holocene sediment core from Lake Karakuli (eastern Pamir, Xinjiang Province, China). Instrumental evidence and isotope-enabled climate model experiments with the Laboratoire de Météorologie Dynamique Zoom model version 4 (LMDZ4) demonstrate that δ D values of precipitation in the region are influenced by both temperature and precipitation amount. We find that these parameters are inversely correlated on an annual scale, i.e., the climate has varied between relatively cool and wet and more warm and dry over the last 50 years. Since the isotopic signals of these changes are in the same direction and therefore additive, isotopes in precipitation are sensitive recorders of climatic changes in the region. Additionally, we infer that plants use year-round precipitation (including snowmelt), and thus leaf wax δ D values must also respond to shifts in the proportion of moisture derived from westerly storms during late winter and early spring. Downcore results give evidence for a gradual shift to cooler and wetter climates between 3.5 and 2.5 cal kyr BP, interrupted by a warm and dry episode between 3.0 and 2.7 kyr BP. Further cool and wet episodes occur between 1.9 and 1.5 and between 0.6 and 0.1 kyr BP, the latter coeval with the Little Ice Age. Warm and dry episodes from 2.5 to 1.9 and 1.5 to 0.6 kyr BP coincide with the Roman Warm Period and Medieval Climate Anomaly, respectively. Finally, we find a drying tend in recent decades. Regional comparisons lead us to infer that the strength and position of the westerlies, and wider northern hemispheric climate dynamics, control climatic shifts in arid Central Asia, leading to complex local responses. Our new archive from Lake Karakuli provides a detailed record of the local signatures of these climate transitions in the eastern Pamir.

Humid Little Ice Age in arid central Asia documented by Bosten Lake, Xinjiang, China

2006 ◽  
Vol 49 (12) ◽  
pp. 1280-1290 ◽  
Author(s):  
Fahu Chen ◽  
Xiaozhong Huang ◽  
Jiawu Zhang ◽  
J. A. Holmes ◽  
Jianhui Chen
Keyword(s):  
Central Asia ◽  
Little Ice Age ◽  
Ice Age ◽  
Bosten Lake ◽  
Arid Central Asia

scholarly journals Humidity changes and possible forcing mechanisms over the last millennium in arid Central Asia

2021 ◽  
Author(s):  
Shengnan Feng ◽  
Xingqi Liu ◽  
Feng Shi ◽  
Xin Mao ◽  
Yun Li ◽  
...  
Keyword(s):  
High Resolution ◽  
Central Asia ◽  
Southern Oscillation ◽  
Atlantic Multidecadal Oscillation ◽  
Warm Period ◽  
Ice Age ◽  
Wavelet Coherence ◽  
Last Millennium ◽  
Arid Central Asia ◽  
Forcing Mechanisms

Abstract. Hydroclimate changes have exerted a significant influence on the historical trajectory of ancient civilizations in arid Central Asia where the central routes of the Silk Road have been hosted. However, the climate changes at different time scales and their possible forcing mechanisms over the last millennium remain unclear due to low-resolution records. Here, we provide a continuous high-resolution humidity history in arid Central Asia over the past millennium based on the ~1.8-year high-resolution multiproxy records with good chronological control from Lake Dalongchi in the central Tianshan Mountains. Generally, the climate was dry during the Medieval Warm Period (MWP) and Current Warm Period (CWP), and wet during the Little Ice Age (LIA), which could be attributed to the influence of the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO). Furthermore, we find that the humidity oscillation was dramatic and unstable at multidecadal to century-scale, especially within the LIA. The continuous wavelet analysis and wavelet coherence show that the humidity oscillation is modulated by the Gleissberg cycle at the century-scale and by the quasi-regular period of El Niño-Southern Oscillation (ENSO) at the multidecadal scale. Our findings suggest that the effect of the solar cycle and the quasi-regular period of ENSO should be seriously evaluated for hydroclimate predictions and climate simulations in arid Central Asia in the future.

scholarly journals Retreat of mountain glaciers of northern Eurasia since the Little Ice Age maximum

2000 ◽  
Vol 31 ◽  
pp. 26-30 ◽  
Author(s):  
Olga N. Solomina
Keyword(s):  
Soviet Union ◽  
Former Soviet Union ◽  
Little Ice Age ◽  
Tien Shan ◽  
Ice Age ◽  
Aerial Photographs ◽  
Northern Eurasia ◽  
Polar Urals ◽  
Mountain Glaciers ◽  
The Pacific

AbstractAnalysis of aerial photographs of about 1000 glaciers located in the mountain ranges of the former Soviet Union –Caucasus, Polar Urals, Pamir-Alay, Tien Shan, Altay, Kodar, Cherskiy range, Suntar-Khayata, Koryakskoye Nagorye, Kamchatka–shows that variations in the magnitude of glacier retreat since the Little Ice Age maximum are significant and probably connected to climatic continentality. On average, the scale of glacier shrinkage is much smaller in continental Siberia than in central Asia and along the Pacific margins.

scholarly journals Dark Clouds over the Silk Road: Challenges Facing Mountain Environments in Central Asia

2020 ◽  
Vol 12 (22) ◽  
pp. 9467
Author(s):  
Roy C. Sidle
Keyword(s):  
Central Asia ◽  
Mineral Resources ◽  
Active Role ◽  
High Elevation ◽  
Silk Road ◽  
Tien Shan ◽  
Remote Communities ◽  
Socioeconomic Impacts ◽  
Mountain Environments ◽  
Ancient Silk Road

Central Asia is a vital link in the huge Chinese Belt and Road Initiative (BRI) that follows much of the ancient Silk Road routes in this region. Other than the economic expansion and trade benefits associated with this complex infrastructure system, little is known about the many of the exogenous issues and direct environmental and socioeconomic impacts surrounding the BRI in Central Asia. This opinion paper takes a sharper look at some of these externalities and potential effects through a sustainability lens. Major environmental concerns focus on the proliferation of spur roads that will develop off upgraded or new Belt Roads to promote exploitation of natural resources. Steep, high-elevation landscapes in the Pamirs and Tien Shan pose problems for road location and construction, and the history of road building in less formidable terrain in Yunnan, China is unsustainable, leading to epic landslide and gully erosion, which degrade river systems. Furthermore, many socioeconomic issues may arise like debt dependencies of poor countries, spread of communicable diseases into remote communities, depletion of mineral resources, and implicit compliance with pro-China policies. While some of the poorer post-Soviet nations can reap short-term benefits from BRI plans, it is urged that they assess the long-term sustainability of BRI development and play an active role in determining the conditions for implementation.

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