scholarly journals The Precipitation Variations in the Qinghai-Xizang (Tibetan) Plateau during 1961-2015

2017 ◽  
Author(s):  
Guoning Wan ◽  
Meixue Yang ◽  
Zhaochen Liu ◽  
Xuejia Wang ◽  
Xiaowen Liang
Keyword(s):  
Spatial Distribution ◽  
Tibetan Plateau ◽  
Precipitation Variability ◽  
Annual Precipitation ◽  
The Tibetan Plateau ◽  
Four Seasons ◽  
Winter Half ◽  
Summer Half ◽  
Surrounding Areas ◽  
Autumn And Winter

The Tibetan Plateau(TP) is known as ‘the water tower of Asian’, its precipitation variation play an important role in the eco-hydrological processes and water resources regimes. based on the monthly mean precipitation data of 65 meteorological stations over the Tibetan Plateau and the surrounding areas from 1961-2015,variations, trends and temporal-spatial distribution were analyzed, furthermore, the possible reasons were also discussed preliminarily. The main results are summarized as follows: the annual mean precipitation in the TP is 465.54mm during 1961-2015, among four seasons, the precipitation in summer accounts for 60.1% of the annual precipitation, the precipitation in summer half year (May.- Oct.) accounts for 91.0% while that in winter half year (Nov.- Apr.) only accounts for 9.0%; During 1961-2015, the annual precipitation variability is 0.45mm/a and the seasonal precipitation variability is 0.31mm/a, 0.13mm/a, -0.04mm/a and 0.04mm/a in spring, summer, autumn and winter respectively on the TP; The spatial distribution of precipitation can be summarized as decreasing from southeast to northwest in the TP, the trend of precipitation is decreasing with the increase of altitude, but the correlation is not significant. The rising of air temperature and land cover changes may cause the precipitation by changing the hydrologic cycle and energy budget, furthermore, different pattern of atmospheric circulation can also influence on precipitation variability in different regions.

scholarly journals Long-term variations in actual evapotranspiration over the Tibetan Plateau

2021 ◽  
Vol 13 (7) ◽  
pp. 3513-3524
Author(s):  
Cunbo Han ◽  
Yaoming Ma ◽  
Binbin Wang ◽  
Lei Zhong ◽  
Weiqiang Ma ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Tibetan Plateau ◽  
Water Cycle ◽  
Meteorological Data ◽  
Correlation Coefficients ◽  
Data Bank ◽  
The Tibetan Plateau ◽  
Science Data ◽  
Autumn And Winter ◽  
Mean Square Errors

Abstract. Actual terrestrial evapotranspiration (ETa) is a key parameter controlling land–atmosphere interaction processes and water cycle. However, spatial distribution and temporal changes in ETa over the Tibetan Plateau (TP) remain very uncertain. Here we estimate the multiyear (2001–2018) monthly ETa and its spatial distribution on the TP by a combination of meteorological data and satellite products. Validation against data from six eddy-covariance monitoring sites yielded root-mean-square errors ranging from 9.3 to 14.5 mm per month and correlation coefficients exceeding 0.9. The domain mean of annual ETa on the TP decreased slightly (−1.45 mm yr−1, p<0.05) from 2001 to 2018. The annual ETa increased significantly at a rate of 2.62 mm yr−1 (p<0.05) in the eastern sector of the TP (long >90∘ E) but decreased significantly at a rate of −5.52 mm yr−1 (p<0.05) in the western sector of the TP (long <90∘ E). In addition, the decreases in annual ETa were pronounced in the spring and summer seasons, while almost no trends were detected in the autumn and winter seasons. The mean annual ETa during 2001–2018 and over the whole TP was 496±23 mm. Thus, the total evapotranspiration from the terrestrial surface of the TP was 1238.3±57.6 km3 yr−1. The estimated ETa product presented in this study is useful for an improved understanding of changes in energy and water cycle on the TP. The dataset is freely available at the Science Data Bank (https://doi.org/10.11922/sciencedb.t00000.00010; Han et al., 2020b) and at the National Tibetan Plateau Data Center (https://doi.org/10.11888/Hydro.tpdc.270995, Han et al., 2020a).

scholarly journals Contrasting Evolution Patterns of Endorheic and Exorheic Lakes on the Central Tibetan Plateau and Climate Cause Analysis during 1988–2017

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1962
Author(s):  
Zhilong Zhao ◽  
Yue Zhang ◽  
Zengzeng Hu ◽  
Xuanhua Nie
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Climatic Factors ◽  
Global Climate ◽  
Rapid Expansion ◽  
Annual Precipitation ◽  
The Tibetan Plateau ◽  
Lake Area ◽  
Climate Change Research ◽  
Mean Temperature

The alpine lakes on the Tibetan Plateau (TP) are indicators of climate change. The assessment of lake dynamics on the TP is an important component of global climate change research. With a focus on lakes in the 33° N zone of the central TP, this study investigates the temporal evolution patterns of the lake areas of different types of lakes, i.e., non-glacier-fed endorheic lakes and non-glacier-fed exorheic lakes, during 1988–2017, and examines their relationship with changes in climatic factors. From 1988 to 2017, two endorheic lakes (Lake Yagenco and Lake Zhamcomaqiong) in the study area expanded significantly, i.e., by more than 50%. Over the same period, two exorheic lakes within the study area also exhibited spatio-temporal variability: Lake Gaeencuonama increased by 5.48%, and the change in Lake Zhamuco was not significant. The 2000s was a period of rapid expansion of both the closed lakes (endorheic lakes) and open lakes (exorheic lakes) in the study area. However, the endorheic lakes maintained the increase in lake area after the period of rapid expansion, while the exorheic lakes decreased after significant expansion. During 1988–2017, the annual mean temperature significantly increased at a rate of 0.04 °C/a, while the annual precipitation slightly increased at a rate of 2.23 mm/a. Furthermore, the annual precipitation significantly increased at a rate of 14.28 mm/a during 1995–2008. The results of this study demonstrate that the change in precipitation was responsible for the observed changes in the lake areas of the two exorheic lakes within the study area, while the changes in the lake areas of the two endorheic lakes were more sensitive to the annual mean temperature between 1988 and 2017. Given the importance of lakes to the TP, these are not trivial issues, and we now need accelerated research based on long-term and continuous remote sensing data.

scholarly journals Continuous Wetting on the Tibetan Plateau during 1970–2017

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2605 ◽  
Author(s):  
Huamin Zhang ◽  
Mingjun Ding ◽  
Lanhui Li ◽  
Linshan Liu
Keyword(s):  
Tibetan Plateau ◽  
Piecewise Linear ◽  
Growing Season ◽  
Significant Trend ◽  
The Tibetan Plateau ◽  
Intensity Analysis ◽  
Standardized Precipitation Evapotranspiration Index ◽  
Piecewise Linear Regression ◽  
Increasing Trend ◽  
Surrounding Areas

Based on daily observation records at 277 meteorological stations on the Tibetan Plateau (TP) and its surrounding areas during 1970–2017, drought evolution was investigated using the Standardized Precipitation Evapotranspiration Index (SPEI). First, the spatiotemporal changes in the growing season of SPEI (SPEIgs) were re-examined using the Mann–Kendall and Sen’s slope approach—the piecewise linear regression and intensity analysis approach. Then, the persistence of the SPEIgs trend was predicted by the Hurst exponent. The results showed that the SPEIgs on the TP exhibited a significant increasing trend at the rate of 0.10 decade−1 (p < 0.05) and that there is no significant trend shift in SPEIgs (p = 0.37), indicating that the TP tended to undergo continuous wetting during 1970–2017. In contrast, the areas surrounding the TP underwent a significant trend shift from an increase to a decrease in SPEIgs around 1984 (p < 0.05), resulting in a weak decreasing trend overall. Spatially, most of the stations on the TP were characterized by an increasing trend in SPEIgs, except those on the Eastern fringe of TP. The rate of drought/wet changes was relatively fast during the 1970s and 1980s, and gradually slowed afterward on the TP. Finally, the consistent increasing trend and decreasing trend of SPEIgs on the TP and the area East of the TP were predicted to continue in the future, respectively. Our results highlight that the TP experienced a significant continuous wetting trend in the growing season during 1970–2017, and this trend is likely to continue.

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 Integrated Geophysical Evidence for the Middle-Lower Crust Melting of the Songpan-Aba Terrain, NE Tibetan Plateau

2021 ◽  
Vol 9 ◽  
Author(s):  
Chongjin Zhao ◽  
Luolei Zhang ◽  
Peng Yu ◽  
Xi Xu
Keyword(s):  
Tibetan Plateau ◽  
Magnetic Layer ◽  
Orogenic Belt ◽  
The Tibetan Plateau ◽  
The West ◽  
Magnetotelluric Data ◽  
West Qinling ◽  
The North ◽  
Weakly Magnetic ◽  
Surrounding Areas

The Songpan−Aba region is located on the northeastern edge of the Tibetan Plateau. Tectonically, the area is surrounded by the West Qinling orogenic belt in the north, the Longmenshan orogenic belt in the southeast, and the East Kunlun and Sanjiang orogenic belts in the west and southwest, forming a triangle that provides an ideal location to study the crust-mantle structure and deep tectonics of the eastward extrusion of the Tibetan Plateau. In this study, the magnetic and electrical structures of the Songpan−Aba area were investigated by inversion using high-precision magnetic anomaly and magnetotelluric data to obtain the subsurface magnetization inversion intensity and resistivity of Songpan–Aba and adjacent areas. The results revealed a continuous magnetic layer up to 20 km below Songpan–Aba and its surrounding areas in the south, possibly originating from a magma root southwest of the Longmenshan massif. In the West Qinling, Songpan–Aba, and Longmenshan areas, pervasive low-resistance, weakly magnetic, or magnetic layers were identified below 20 km that might be formed from the molten mantle material extruded from the eastern edge of the Tibetan Plateau.

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