Influence of the Tibetan Plateau and its northern margins on the mid-latitude Westerly Jet over Central Asia in summer

2020 ◽  
Vol 544 ◽  
pp. 109611 ◽  
Author(s):  
Yingying Sha ◽  
Xin Ren ◽  
Zhengguo Shi ◽  
Peng Zhou ◽  
Xinzhou Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Central Asia ◽  
The Tibetan Plateau ◽  
Westerly Jet

Seasonal variation of westerly jet over Asia in Last Glacial Maximum: Role of the Tibetan Plateau heating

2021 ◽  
pp. 1
Author(s):  
Jing Lei ◽  
Zhengguo Shi ◽  
Xiaoning Xie ◽  
Yingying Sha ◽  
Xinzhou Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Central Asia ◽  
Last Glacial Maximum ◽  
General Circulation ◽  
Heat Budget ◽  
Glacial Maximum ◽  
The Tibetan Plateau ◽  
Last Glacial ◽  
Westerly Jet

AbstractThe westerly jet (WJ) is an important component of atmospheric circulation, which is characterized by prominent seasonal variations in intensity and position. However, the response of WJ over Asia during the Last Glacial Maximum (LGM) is still not clear. Using general circulation model experiments, the seasonal behaviors of WJ over Central Asia and Japan are analyzed in this paper. The results show that, compared to present day (PD), the WJ presents a complicated response during the LGM, both in intensity and position. Over Central Asia, it becomes weaker in both summer and winter. But over Japan, it is enhanced in summer but becomes diminished in winter. In terms of position, the WJ over Central Asia shifts southwards in both summer and winter, while the WJ over Japan moves southwards in summer but does not change obviously relative to PD in winter. Such WJ changes are well explained by meridional temperature gradients in high troposphere, which is closely linked to seasonal thermal anomalies over the Tibetan Plateau (TP). Despite of cooler LGM condition, the anomalous warming center over TP becomes stronger in summer. Derived from the heat budget equation, the stronger heating center is mainly caused by the weaker adiabatic cooling generated from ascending motion over south of TP. In winter, the cooling over TP is also strengthened and mostly owes to the subsidence-induced weaker adiabatic heating. Due to the importance of WJ, the potential role of TP thermal effect should be focused when explaining the East Asian climate change during the LGM.

New Noctuidae species from China (Lepidoptera, Noctuoidea)

Zootaxa ◽  
2011 ◽  
Vol 2896 (1) ◽  
pp. 46
Author(s):  
P. GYULAI ◽  
L. RONKAY ◽  
A. SALDAITIS
Keyword(s):  
New Species ◽  
Tibetan Plateau ◽  
Central Asia ◽  
New Taxa ◽  
Light Trapping ◽  
Himalayan Region ◽  
Research Centre ◽  
The Tibetan Plateau ◽  
The Third ◽  
High Diversity

Collecting expeditions to China's Sichuan, Gansu and Qinghai provinces were conducted by the third author, along with Alessandro and Irene Floriani, during June 2009, April 2010 and July 2010. Light trapping yielded numerous noctuid moths including four new species, described herein. These new taxa reflect the high diversity of some genera (Hada, Billberg, 1820 ; Palaeamathes, Boursin, 1954) in SW China, and the biogeographical connections of the Tibetan Plateau to Central Asia (Lacanobia kitokia sp. n., L. contrastata (Bryk, 1942), L. mongolica Behounek, 1993, L. kirghisa Gyulai & Ronkay, 1998) and to the Himalayan Region (Palaeamathes serrulata sp. n. is close to P. harpegnoma (Hreblay & Ronkay, 1998). Acronyms for personal and institutional collections are as follows: AFM—Alessandro Floriani (Milan, Italy); ASV—Aidas Saldaitis (Vilnius, Lithuania); BJ—Janos Babics (Budapest, Hungary); DNK—Danny Nilsson (Kalvehave, Denmark); GRB—Gabor Ronkay (Budapest, Hungary); GBG/ZSM—Gottfried Behounek (Grafing, Germany) / Zoologische Staatssammlung, München (Germany); GYP—Peter Gyulai (Miskolc, Hungary); HHP – Henri Hoppe (Klein Pravtshagen, Germany); NRCV—Nature Research Centre (Vilnius, Lithuania); WSM—Wolfgang Speidel (München, Germany).

scholarly journals Seasonal Features and a Case Study of Tropopause Folds over the Tibetan Plateau

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Jiali Luo ◽  
Wenjun Liang ◽  
Pingping Xu ◽  
Haiyang Xue ◽  
Min Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
High Frequency ◽  
Reanalysis Data ◽  
The Tibetan Plateau ◽  
Transport Pathway ◽  
Westerly Jet ◽  
Meridional Winds ◽  
Surrounding Areas ◽  
High Potential Vorticity

Tropopause fold is the primary mechanism for stratosphere-troposphere exchange (STE) at the midlatitudes. Investigation of the features of tropopause folds over the Tibetan Plateau (TP) is important since the TP is a hotspot in global STE. In this study, we investigated seasonal features of the tropopause fold events over the TP using the 40-year ERA-Interim reanalysis data. The development of a tropopause folding case is specifically examined. The results show that shallow tropopause folds occur mostly in spring, while medium and deep folds occur mostly in winter. The multiyear mean monthly frequency of shallow tropopause folds over the TP reaches its maximum value of about 7% in May and then decreases gradually to its minimum value of 1% in August and increases again since September. Deep folds rarely occur in summer and autumn. Both the seasonal cycle and seasonal distribution of total tropopause folds over the TP are dominated by shallow folds. The relative high-frequency areas of medium and deep folds are located over the southern edge of the TP. The westerly jet movement controls the displacement of the high-frequency folding region over the TP. The region of high-frequency tropopause folds is located in the southern portion of the plateau in spring and moves northward in summer. The jet migrates back to the south in autumn and is located along about 30°N in winter, and the region where folds occur most frequently also shifts southward correspondingly. A medium fold event that occurred on 29 December 2018 is used to demonstrate the evolution of a tropopause fold case over the TP in winter; that is, the folding structure moves from west to east, the tropopause pressure is greater than 320 hPa over the folding region, while it is about 200 hPa in the surrounding areas, and the stratospheric air with high potential vorticity (PV) is transported from the high latitudes to the plateau by meridional winds. A trajectory model result verifies the transport pathway of the air parcels during the intrusion event.

scholarly journals Changing Pattern of Water Level Trends in Eurasian Endorheic Lakes as a Response to the Recent Climate Variability

2021 ◽  
Vol 13 (18) ◽  
pp. 3705
Author(s):  
Xin Zhang ◽  
Abilgazi Kurbaniyazov ◽  
Georgiy Kirillin
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Central Asia ◽  
Climatic Factors ◽  
Hydrological Regime ◽  
Water Levels ◽  
The Tibetan Plateau ◽  
Lake Levels ◽  
Mongolian Plateau ◽  
Recent Climate

Lake level is a sensitive integral indicator of climate change on regional scales, especially in enclosed endorheic basins. Eurasia contains the largest endorheic zone with several large terminal lakes, whose water levels recently underwent remarkable variations. To address the patterns of these variations and their links to the climate change, we investigated the variability of levels in 15 lakes of three neighboring endorheic regions—Central Asia, Tibetan Plateau, and Mongolian Plateau. Satellite altimetry revealed a heterogeneous pattern among the regions during 1992–2018: lake levels increased significantly in Central Asia and the Tibetan Plateau but decreased on the Mongolian Plateau. The shifts to the increasing trend were detected since 1997 in Central Asia, since 1998 in the southern part of the Tibetan Plateau, and since 2005 in its northern part. The shift in air temperatures around 1997 and the precipitation shifts around 1998 and 2004 contributed to the trend’s turning points, with precipitation being the major contributor to the heterogeneous pattern of lake levels. Our findings reveal the linkage of the heterogeneous pattern of lake levels to climatic factors in the endorheic basins, providing a further understanding of the hydrological regime in the Eurasian endorheic zone and its sensitivity to climate change.

Role of Tibetan Plateau in Northern Drought induced by Changes in Subtropical Westerly Jet

2021 ◽  
pp. 1-40
Author(s):  
Qingzhe Zhu ◽  
Yuzhi Liu ◽  
Tianbin Shao ◽  
Run Luo ◽  
Ziyuan Tan
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
North China ◽  
Lower Troposphere ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Westerly Jet ◽  
The Impact ◽  
Subtropical Westerly Jet

AbstractThe Tibetan Plateau (TP), the “Water Tower of Asia”, plays an important role in the water cycle. However, few studies have linked the TP’s water vapor supply with the climate over North China. In this study, we found that changes in the subtropical westerly jet (SWJ) dynamically induce drought in North China, and the TP plays an important role in this relationship. During July-August for the period of 1981-2019, the SWJ center between 75°E and 105°E obviously shifted northward at a rate of 0.04° per year. Correspondingly, the zonal winds in the southern subtropics were incredibly weakened, causing the outflow of water vapor from the TP to decrease dramatically. Combined with numerical simulations, we discovered that a reduction in water vapor transport from the TP can obviously decrease the precipitation over North China. Sensitivity experiments demonstrated that if the water vapor outflow from the eastern border of the TP decreases by 52.74%, the precipitation in North China will decrease by 12.69% due to a decrease in the local cloud fraction caused by a diminished water vapor content in the atmosphere. Therefore, although less water vapor transport occurs in the upper troposphere than in the lower troposphere, the impact of transport from the TP in the former on the downstream precipitation cannot be ignored.

East‐Central Asian Climate Evolved With the Northward Migration of the High Proto‐Tibetan Plateau

2021 ◽  
Author(s):  
Chenguang Zhu
Keyword(s):  
Tibetan Plateau ◽  
Central Asia ◽  
Climate Changes ◽  
Climate Modeling ◽  
East Asian ◽  
Precipitation Pattern ◽  
The Tibetan Plateau ◽  
Central Asian ◽  
Global Cooling ◽  
Climate Patterns

<div>The evolution of Cenozoic climate patterns in Asia has been linked to uplift of the Tibetan Plateau (TP), retreat of the Paratethys Sea, and global cooling. However, less attention has been placed on the latitudinal change of the TP. Here we report new climate modeling to explore how modern climate changes as a function of topographic growth and spatial migration of the TP. Our results show that the northward displacement of the uplifted proto‐TP within the subtropics can signifificantly affect the wind and precipitation pattern over East‐Central Asia. By compiling proxy‐based climatic records, paleolatitudinal and paleoelevational evolution models of the proto‐TP, and in comparison with previous modeling under a global paleogeography, we suggest that the northward migration of the proto‐TP in the Paleogene could have intensifified the aridity in Central Asia, but its inflfluence on East Asian precipitation and monsoonal circulation could be dependent on the paleogeography and other boundary conditions.</div>

scholarly journals Changes in Moisture Flux over the Tibetan Plateau during 1979–2011 and Possible Mechanisms

2014 ◽  
Vol 27 (5) ◽  
pp. 1876-1893 ◽  
Author(s):  
Yanhong Gao ◽  
Lan Cuo ◽  
Yongxin Zhang
Keyword(s):  
Tibetan Plateau ◽  
Moisture Flux ◽  
Monsoon Circulation ◽  
The Tibetan Plateau ◽  
Transient Eddy ◽  
Wet Season ◽  
Dynamic Component ◽  
Westerly Jet ◽  
East Asian Westerly Jet ◽  
Spatially Varying

Abstract Changes in moisture as represented by P − E (precipitation − evapotranspiration) and the possible causes over the Tibetan Plateau (TP) during 1979–2011 are examined based on the Global Land Data Assimilation Systems (GLDAS) ensemble mean runoff and reanalyses. It is found that the TP is getting wetter as a whole but with large spatial variations. The climatologically humid southeastern TP is getting drier while the vast arid and semiarid northwestern TP is getting wetter. The Clausius–Clapeyron relation cannot be used to explain the changes in P − E over the TP. Through decomposing the changes in P − E into three major components—dynamic, thermodynamic, and transient eddy components—it is noted that the dynamic component plays a key role in the changes of P − E over the TP. The thermodynamic component contributes positively over the southern and central TP whereas the transient eddy component tends to reinforce (offset) the dynamic component over the southern and parts of the northern TP (central TP). Seasonally, the dynamic component contributes substantially to changes in P − E during the wet season, with small contributions from the thermodynamic and transient eddy components. Further analyses reveal the poleward shift of the East Asian westerly jet stream by 0.7° and poleward moisture transport as well as the intensification of the summer monsoon circulation due to global warming, which are shown to be responsible for the general wetting trend over the TP. It is further demonstrated that changes in local circulations that occur due to the differential heating of the TP and its surroundings are responsible for the spatially varying changes in moisture over the TP.

scholarly journals Large-scale atmospheric circulation control on stable water isotopes in precipitation over the northwestern and southeastern Tibetan Plateau

2016 ◽  
Author(s):  
Xiaoxin Yang ◽  
Sunil Acharya ◽  
Tandong Yao
Keyword(s):  
Tibetan Plateau ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Southern Oscillation ◽  
Asian Summer Monsoon ◽  
The Tibetan Plateau ◽  
Stable Water Isotopes ◽  
South Asian Summer Monsoon ◽  
Westerly Jet ◽  
Large Scale Atmospheric Circulation

Abstract. The mid-latitude westerlies and South Asian Summer Monsoon (SASM) are two major atmospheric circulation systems influencing the Tibetan Plateau (TP). We report a seven-year (2007/2008–2013/2014) dataset of δ18O in precipitation (δ18Op) collected at three stations. Taxkorgan (TX) and Bulunkou (BLK) are located on the northwestern TP where westerly winds dominate while Lulang (LL) is situated on the southeastern TP where the SASM dominates. δ18O in precipitation (δ18Op) in northwestern TP varies with surface temperature (T) throughout the study period, and is depleted in 18O in precipitation during June to September when the monsoonal circulation enters the TP. Integration with model outputs suggests that large-scale atmospheric circulation plays a major role in isotopic seasonality in both regions. A teleconnection between precipitation on the northwestern TP and the El Niño-Southern Oscillation (ENSO) warm phase is suggested by changes in the relationship between δ18O and δD (e.g., reduced slope and weighted d-excess) in precipitation samples. These observations are indicative of a weakening of the mid-latitude westerly jet allowing local processes in the continental interior to become more dominant, thereby increasing the contribution of secondary evaporation from falling raindrops and kinetic fractionation. Under the conditions of a high Northern Annular Mode (NAM) the westerly jet is intensified over the southeastern TP which enhances local evaporation and continental recycling as revealed by a lower δD-δ18O slope and intercept, but higher d-excess average in contemporaneously collected precipitation samples. The significant correlation between T and δ18Op in the northwestern TP during various composite periods highlights a variation from 0.39 ‰ / ℃ (ENSO warm) to 0.77 ‰ / ℃ (high NAM), attributable to decreased (increased) water vapor availability over the northwestern TP during the ENSO warm (strong positive NAM) phase. ENSO cold and strong negative NAM phases show analogous effects on atmospheric circulation over both regions.

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