Mantle dynamics, uplift of the Tibetan Plateau, and the Indian Monsoon

1993 ◽  
Vol 31 (4) ◽  
pp. 357 ◽  
Author(s):  
Peter Molnar ◽  
Philip England ◽  
Joseph Martinod
Keyword(s):  
Tibetan Plateau ◽  
Indian Monsoon ◽  
The Tibetan Plateau ◽  
Mantle Dynamics

scholarly journals Spatial Distribution of the Persistent Organic Pollutants across the Tibetan Plateau and Its Linkage with the Climate Systems: Five Year Air Monitoring Study

2016 ◽  
Author(s):  
Xiaoping Wang ◽  
Jiao Ren ◽  
Ping Gong ◽  
Chuanfei Wang ◽  
Yonggang Xue ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Time Trends ◽  
Indian Monsoon ◽  
Temporal Trends ◽  
Sampling Period ◽  
The Tibetan Plateau ◽  
Transport Pathways ◽  
Air Masses

Abstract. The Tibetan Plateau (TP) has been contaminated by persistent organic pollutants (POPs), including legacy organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) through atmospheric transport. The exact source regions, transport pathways and time trends of POPs to the TP are not well understood. Here XAD-based passive air samplers (PAS) were deployed at 16 Tibetan background sites from 2007 to 2012 to gain further insight into spatial patterns and temporal trends of OCPs and PCBs. The southeastern TP was characterized by dichlorodiphenyltrichloroethane (DDT) -related chemicals delivered by Indian Monsoon air masses. The northern and northwestern TP displayed the greatest absolute concentration and relative abundance of hexachlorobenzene (HCB) in the atmosphere, caused by the westerly-driven European air masses. The interactions between the DDT polluted Indian monsoon air and the clean westerly winds formed a transition zone in central Tibet where both DDT and HCB were the dominant chemicals. Based on 5-year of continuous sampling, our data indicated declining concentrations of HCB and hexachlorocyclohexanes (HCHs) across the Tibetan region. Inter-annual trends of DDT class chemicals, however, showed less variation during this 5-year sampling period, which may be due to the on-going usage of DDT in India. This paper demonstrates the possibility of using POPs fingerprints to investigate the climate interactions and the validity of using PAS to derive inter-annual atmospheric POPs time trends.

Complex Role of the Tibetan Plateau and its Surrounding Topography in the Formation of Asian Climate

2020 ◽  
Author(s):  
Yingying Sha ◽  
Zhengguo Shi
Keyword(s):  
Tibetan Plateau ◽  
Asian Monsoon ◽  
Indian Monsoon ◽  
Arid Climate ◽  
Monsoon Circulation ◽  
Main Body ◽  
The Tibetan Plateau ◽  
Strengthening Effect ◽  
Maximum Rainfall ◽  
Precipitation Seasonality

<p>The Tibetan Plateau (TP) has undoubtedly played an essential role in the evolution and strengthening of the coupled climate system of the Asian monsoon and inland arid climate since the Cenozoic. However, a growing number of studies have found that regional and relatively smaller scale topography also has significant impact on Asian climate.<br>By using high resolution atmospheric circulation model, we analyzed the effect of the main body of the TP and its surrounding topography on the evolution of Asian climate. The surrounding topography includes the Yunnan-Guizhou Plateau (YG) at the southeastern margin of the Tibetan Plateau, the Pamir Plateau (Pr) and Tian Shan mountains (TS) at the northern margin and the Mongolian Plateau (MP) further north. The results show that different from the strengthening effect of the main TP, the YG significantly weakens the Indian monsoon. With the uplift of the YG, an anomalous anticyclonic circulation appeared in the lower troposphere over the southwest, resulting in the weakening of monsoon circulation from the Bay of Bengal to the Indian subcontinent and the Arabian sea. The decline in Indian monsoon precipitation caused by the YG accounts for one-third of the total increase in precipitation caused by the entire TP.<br>For the arid interior Asia, the main TP, YG, Pr and TS, as well as the MP all have reduced the annual precipitation in some extent. However, different from the consistent inhibiting effect of the main TP on the precipitation over the arid interior Asia throughout the year, the decreasing effect of the YG and the MP is mainly effective in boreal winter, which is closely related to the mechanical blocking effect. In addition, the Pr and TS play a key role in the temporal and spatial differentiation of precipitation in the arid interior Asia. Before the appearance of the Pr and TS, the precipitation seasonality over the eastern sub-region was characterized with maximum rainfall in spring and winter and minimum rainfall in summer. With the uplift of Pr and TS, the precipitation over the eastern part decreases in winter and significantly increases in summer, which leads to the change of precipitation seasonality to summer dominated.<br>The above results indicate that different part of the extensive-third pole have different influences on the Asian monsoon and inland aridity. It suggests that the Asian monsoon-inland arid climate may have undergone complex evolutionary processes on tectonic scale.</p>

Mantle convection beneath East Asia under global mantle convection spherical framework

2020 ◽  
Author(s):  
Qunfan Zheng ◽  
Huai Zhang
Keyword(s):  
Tibetan Plateau ◽  
East Asia ◽  
Upper Mantle ◽  
Mantle Convection ◽  
Mantle Flow ◽  
The Tibetan Plateau ◽  
Mantle Structure ◽  
Lithospheric Deformation ◽  
Mantle Dynamics ◽  
Flow Models

<p>East Asia is a tectonically active area on earth and has a complicated lithospheric deformation due to the western Indo-Asian continental collision and the eastern oceanic subduction mainly from Pacific plate. Till now, mantle dynamics beneath this area is not well understood due to its complex mantle structure, especially in the framework of global spherical mantle convection. Hence, a series of numerical models are conducted in this study to reveal the key controlling parameters in shaping the present-day observed mantle structure beneath East Asia under 3-D global mantle flow models. Global mantle flow models with coarse mesh are firstly applied to give a rough constraint on global mantle convection. The detailed description of upper mantle dynamics of East Asia is left with regional refined mesh. A power-law rheology and absolute plate field are applied subsequently to get a better constraint on the related regional mantle rheological structure and surficial boundary conditions. Thus, the refined and reasonable velocity and stress distributions of upper mantle beneath East Asia at different depths are retrieved based on our 3-D global mantle flow simulations. The derived large shallow mantle flow beneath the Tibetan Plateau causes significant lithospheric shear drag and dynamic topography that result in prominent tectonic evolution of this area. And the Indo–Asian collision may have induced mantle flow beneath the Indian plate and the different velocity structures between the asthenosphere and lithosphere indicate the shear drag of asthenospheric mantle. That may explain the reason that Indo–Asian collision has occurred for 50 Ma, and this collision can still continue to accelerate uplift in the Tibetan plateau. Finally, we also consider the possible implementations of 3-D numerical simulations combined with global lithosphere and deep mantle dynamics so as to discuss the relevant influences.</p>

Rapid northward shift of the Indian Monsoon on the Tibetan Plateau at the end of the Little Ice Age

2017 ◽  
Vol 122 (17) ◽  
pp. 9262-9279 ◽  
Author(s):  
Xiaolong Zhang ◽  
Baiqing Xu ◽  
Franziska Günther ◽  
Roman Witt ◽  
Mo Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Little Ice Age ◽  
Indian Monsoon ◽  
Ice Age ◽  
The Tibetan Plateau

Thermodynamic Bias in the Multimodel Mean Boreal Summer Monsoon*

2013 ◽  
Vol 26 (7) ◽  
pp. 2279-2287 ◽  
Author(s):  
William R. Boos ◽  
John V. Hurley
Keyword(s):  
Tibetan Plateau ◽  
Climate Model ◽  
Indian Monsoon ◽  
Boreal Summer ◽  
The Tibetan Plateau ◽  
Tropospheric Temperature ◽  
Moist Convection ◽  
Monsoon Precipitation ◽  
Thermodynamic State ◽  
Western Asia

Abstract Here it is shown that almost all models participating in the Coupled Model Intercomparison Project (CMIP) exhibit a common bias in the thermodynamic structure of boreal summer monsoons. The strongest bias lies over South Asia, where the upper-tropospheric temperature maximum is too weak, is shifted southeast of its observed location, and does not extend as far west over Africa as it does in observations. Simulated Asian maxima of surface air moist static energy are also too weak and are located over coastal oceans rather than in their observed continental position. The spatial structure of this bias suggests that it is caused by an overly smoothed representation of topography west of the Tibetan Plateau, which allows dry air from the deserts of western Asia to penetrate the monsoon thermal maximum, suppressing moist convection and cooling the upper troposphere. In a climate model with a decent representation of the thermodynamic state of the Asian monsoon, the qualitative characteristics of this bias can be recreated by truncating topography just west of the Tibetan Plateau. This relatively minor topographic modification also produces a negative anomaly of Indian precipitation of similar sign and amplitude to the CMIP continental Indian monsoon precipitation bias. Furthermore, in simulations of next-century climate warming, this topographic modification reduces the amplitude of the increase in Indian monsoon precipitation. These results confirm the importance of topography west of the Tibetan Plateau for South Asian climate and illustrate the need for careful assessments of the thermodynamic state of model monsoons.

scholarly journals Late quaternary climate, precipitation δ 18 O, and Indian monsoon variations over the Tibetan Plateau

2017 ◽  
Vol 457 ◽  
pp. 412-422 ◽  
Author(s):  
Jingmin Li ◽  
Todd A. Ehlers ◽  
Martin Werner ◽  
Sebastian G. Mutz ◽  
Christian Steger ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Indian Monsoon ◽  
Late Quaternary ◽  
The Tibetan Plateau ◽  
Quaternary Climate

Effect of Yunnan–Guizhou Topography at the Southeastern Tibetan Plateau on the Indian Monsoon

2017 ◽  
Vol 30 (4) ◽  
pp. 1259-1272 ◽  
Author(s):  
Zhengguo Shi ◽  
Yingying Sha ◽  
Xiaodong Liu
Keyword(s):  
Tibetan Plateau ◽  
General Circulation ◽  
Indian Monsoon ◽  
Indian Subcontinent ◽  
Circulation Model ◽  
Summer Precipitation ◽  
Monsoon Circulation ◽  
The Tibetan Plateau ◽  
Southeastern Margin ◽  
Open Question

Abstract Topographic insulation is one of the primary origins for the influence of the Tibetan Plateau (TP) on Asian climate. The Yunnan–Guizhou (YG) Plateau, at the southeastern margin of the TP, is known to block the northern branch of the Indian monsoon circulation in summer. However, it is an open question whether this blocking feeds back to the monsoon. In this study, the effect of the YG topography on the Indian monsoon and its comparison with that of the TP were evaluated using general circulation model experiments. The results showed that the TP strengthens the monsoon precipitation, especially during the onset. However, the YG topography significantly weakens the monsoon. With the YG topography, strengthened low-level airflow around the YG Plateau induces anomalous anticyclonic winds to the southwest, and the changes remodulate the whole circulation structure over Asia. As a result, the Indian monsoon becomes weakened from the Bay of Bengal to the Indian subcontinent and Arabian Sea, as does the associated precipitation. In addition, the YG topography affects the anomalous warming center over the TP and the precipitation during the monsoon onset. The YG-reduced summer precipitation occupied approximately one-third of the total increment compared to the entire TP. The Indian monsoon weakened by YG topography distinctly opposes the traditional paleoclimatic viewpoint that all of the TP topography contributes to the monsoon strengthening. In fact, the climatic effect of the TP depends closely upon both its central and marginal topography, and the topography of its subterrains does not necessarily play a similar role.

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