Evolution of a Mesospheric Bore in a Duct Observed by Ground‐Based Double‐Layer Imagers and Satellite Observations Over the Tibetan Plateau Region

2019 ◽  
Vol 124 (2) ◽  
pp. 1377-1388 ◽  
Author(s):  
Qinzeng Li ◽  
Jiyao Xu ◽  
Jia Yue ◽  
Xiao Liu ◽  
Wei Yuan
2020 ◽  
Vol 7 (3) ◽  
pp. 516-533 ◽  
Author(s):  
Jianchun Bian ◽  
Dan Li ◽  
Zhixuan Bai ◽  
Qian Li ◽  
Daren Lyu ◽  
...  

Abstract Due to its surrounding strong and deep Asian summer monsoon (ASM) circulation and active surface pollutant emissions, surface pollutants are transported to the stratosphere from the Tibetan Plateau region, which may have critical impacts on global climate through chemical, microphysical and radiative processes. This article reviews major recent advances in research regarding troposphere–stratosphere transport from the region of the Tibetan Plateau. Since the discovery of the total ozone valley over the Tibetan Plateau in summer from satellite observations in the early 1990s, new satellite-borne instruments have become operational and have provided significant new information on atmospheric composition. In addition, in situ measurements and model simulations are used to investigate deep convection and the ASM anticyclone, surface sources and pathways, atmospheric chemical transformations and the impact on global climate. Also challenges are discussed for further understanding critical questions on microphysics and microchemistry in clouds during the pathway to the global stratosphere over the Tibetan Plateau.


Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2805
Author(s):  
Sansan Feng ◽  
Hongwei Lu ◽  
Tianci Yao

Microplastics (MPs) are ubiquitous in the environment and have been drawing increasing attention; however, MPs’ occurrence and behavior in remote areas are not well understood. In this study, we quantified and characterized MPs from surface waters and sediments in a remote area, namely the Tibetan Plateau, China. The samples were collected from the Lhasa River and the lower reaches of the Brahmaputra River to better understand MPs’ sources to rivers of the Tibetan Plateau. MPs’ concentrations in water and sediment were 735 items/m3 and 51 items/kg, respectively, and the dominating MPs observed were fibers with size ranging from 100 to 500 µm. MP abundance increased nearly two-fold from upstream to downstream in the Brahmaputra River, associated with the inputs from downstream human activities and the inflows of tributaries (especially the Lhasa River). This study provides important bases for analyzing MPs migration processes in the plateau region.


2020 ◽  
Vol 211 ◽  
pp. 103408
Author(s):  
Zhiwen Dong ◽  
Janice Brahney ◽  
Shichang Kang ◽  
James Elser ◽  
Ting Wei ◽  
...  

2006 ◽  
Vol 43 ◽  
pp. 369-377 ◽  
Author(s):  
Kunio Rikiishi ◽  
Haruka Nakasato

AbstractThe dataset of Northern Hemisphere EASE-Grid Weekly Snow Cover and Sea Ice Extent for the period October 1966-July 2001 is analyzed to examine the height dependence of declining tendencies of seasonal snow cover in the Himalaya and the Tibetan Plateau region (25−45˚ N, 70−110˚E). It is found that the annual mean snow-covered area is decreasing in the Himalaya/Tibet region at a rate of ∼ 1 % a−1, implying that the mean snow-covered area has decreased by one-third from 1966 to 2001. The rate of decrease is largest (1.6%) at the lowest elevations (0−500 m). On the other hand, the length of the snow-cover season is declining at all elevations, with the greatest rate of decline in the 4000−6000 m height range. On the Tibetan Plateau (∼4000−6000 m a.s.l.), the length of the snow-cover season has decreased by 23 days, and the end date for snow cover has advanced by 41 days over this 35 year period. These rates might be somewhat overestimated by the binary definition of snow cover on satellite images. It is likely that the reduction of the snow surface albedo by deposition of Asian dust and anthropogenic aerosols may be at least partly responsible for earlier snowmelt.


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