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Zhao L, Dong X, Liu X, Wang N, Eastoe CJ, Wei N, Xie C, Liu H, Han C, Hua T, Wang L. Extreme precipitation stable isotopic compositions reveal unexpected summer monsoon incursions in the Qilian Mountains. Sci Total Environ 2023; 900:165743. [PMID: 37495157 DOI: 10.1016/j.scitotenv.2023.165743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/16/2023] [Accepted: 07/21/2023] [Indexed: 07/28/2023]
Abstract
Isotope composition and moisture sources of precipitation are important for understanding water cycles and reconstructing paleoclimate. Based on 15-years' precipitation stable Isotope composition (δ18O and δ2H) from four stations of the Qilian Mountains, we found unique δ18O and δ2H features associated with the incursion of the summer monsoon over the Qilian Mountains, northwestern China. In 12 of the 15 years, similar seasonal variations of δ18O and δ2H confirmed a dominant source of moisture from Westerly circulation, and higher intercepts of the local meteoric water line (LMWL) indicated strong recycling of continental moisture. However, in August 2016 and 2018, extremely low slopes and intercepts of the LMWL, and more negative δ18O and δ2H revealed substantial contributions of the Asian summer monsoon to precipitation of the Qilian Mountains, with extremely heavy precipitation in August 2016. The column moisture flux, land-sea thermal contrast, correlations of precipitation δ18O with East Asian Summer Monsoon Index and Westerlies Index, HYSPLIT modeling results and precipitation δ18O along backward trajectories confirmed incursions of the summer monsoon in August 2016 and 2018. Our redefining of the boundary of the summer monsoon region confirmed the summer monsoon incursion zone can extend to the west of longitude 96°E and north of latitude 40°N in strong monsoon years, corresponding to boundaries of monsoon incursions in the mid-Holocene. Temperature correlated with precipitation δ18O at monthly and shorter time scales, but not for whole seasons or at yearly scale, revealing that summer monsoon incursions are therefore more likely than changing temperature to explain the multi-year cycles in the Qilian Mountains ice archives. Continent-scale shifts in atmospheric circulation strongly influence water resources in the Qilian mountains, and may change in frequency as climate warms. This study therefore has important implications for understanding water resources in the Qilian mountains in the past and into the future.
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Affiliation(s)
- Liangju Zhao
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China.
| | - Xiying Dong
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China
| | - Xiaohong Liu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Ninglian Wang
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China
| | - Christopher J Eastoe
- Department of Geosciences (retired), University of Arizona, Tucson, AZ 85721, USA
| | - Na Wei
- Climate Centre of Shaanxi Province, Xi'an 710049, China
| | - Cong Xie
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China
| | - Hang Liu
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China
| | - Chuntan Han
- Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Ting Hua
- Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China
| | - Lixin Wang
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, IN 46202, USA
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Zhao C, Liang J, Zhu M, Zheng S, Zhao Y, Sun X. Occurrence, characteristics, and factors influencing the atmospheric microplastics around Jiaozhou Bay, the Yellow Sea. Mar Pollut Bull 2023; 196:115568. [PMID: 37783164 DOI: 10.1016/j.marpolbul.2023.115568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 09/11/2023] [Accepted: 09/19/2023] [Indexed: 10/04/2023]
Abstract
Atmospheric microplastics are attracting increasing attention as an emerging pollutant. However, research on its characteristics and influencing factors is insufficient. This study examines the characteristics and spatiotemporal distribution of atmospheric microplastics around Jiaozhou Bay, the Yellow Sea. The results showed that the dominant shapes of microplastic were fragments (61.9 %) and fibers (25.6 %), and the main types were polyethylene terephthalate (23.8 %), polyethylene (31.6 %) and cellulose (rayon, 34.9 %). The deposition rate of microplastic varied from 8.395 to 80.114 items·m-2·d-1, with a mean of 46.708 ± 21.316 items·m-2·d-1. The deposition rate was higher in the dry season than in the rainy season, indicating the influence of weather condition. The annual mass of atmospheric microplastics entering the bay was estimated to be 7.612 ± 3.474 tons. For the first time, this study reveals that atmospheric microplastics in Jiaozhou Bay change spatiotemporally due to monsoons, which pose a potential threat to marine ecosystems.
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Affiliation(s)
- Chenhao Zhao
- Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junhua Liang
- Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, 266237, PR China
| | - Mingliang Zhu
- Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, 266237, PR China
| | - Shan Zheng
- Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, 266237, PR China
| | - Yongfang Zhao
- Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, 266237, PR China
| | - Xiaoxia Sun
- Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, 266237, PR China; Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Siu LW, Bowman KP. Unsteady Vortex Behavior in the Asian Monsoon Anticyclone. J Atmos Sci 2020; 77:4067-4088. [PMID: 33390614 PMCID: PMC7774506 DOI: 10.1175/jas-d-19-0349.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The Asian monsoon anticyclone (AMA), which is primarily driven by the latent heat released by monsoon precipitation, is one of the dominant features of the Northern Hemisphere summer circulation in the upper troposphere and lower stratosphere. Due to variations in the diabatic heating, interactions with Rossby waves propagating along the subtropical jet, and internal dynamics within the anticyclone, the circulation of the AMA is unsteady. Here we use the ERA-Interim dataset and trajectories computed with ERA-Interim winds to show that the AMA contains two or three distinct synoptic-scale subvortices 69% of the time, while a single circulation center is present only 23% of the time. More than three simultaneous subvortices are uncommon. Observed behaviors of the subvortices include 1) splitting of a single vortex into two vortices; 2) merger of two vortices into a single vortex; 3) vortex shedding in the eastward direction; 4) vortex shedding in the westward direction; and 5) formation, movement, and dissipation of a vortex. The evolution of the subvortices is closely tied to stirring and transport.
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Affiliation(s)
- Leong Wai Siu
- Department of Atmospheric Sciences, Texas A&M University, College Station, Texas
- Current affiliation: Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York
| | - Kenneth P. Bowman
- Department of Atmospheric Sciences, Texas A&M University, College Station, Texas
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Spicer RA. Tibet, the Himalaya, Asian monsoons and biodiversity - In what ways are they related? Plant Divers 2017; 39:233-244. [PMID: 30159517 PMCID: PMC6112286 DOI: 10.1016/j.pld.2017.09.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 05/08/2023]
Abstract
Prevailing dogma asserts that the uplift of Tibet, the onset of the Asian monsoon system and high biodiversity in southern Asia are linked, and that all occurred after 23 million years ago in the Neogene. Here, spanning the last 60 million years of Earth history, the geological, climatological and palaeontological evidence for this linkage is reviewed. The principal conclusions are that: 1) A proto-Tibetan highland existed well before the Neogene and that an Andean type topography with surface elevations of at least 4.5 km existed at the start of the Eocene, before final closure of the Tethys Ocean that separated India from Eurasia. 2) The Himalaya were formed not at the start of the India-Eurasia collision, but after much of Tibet had achieved its present elevation. The Himalaya built against a pre-existing proto-Tibetan highland and only projected above the average height of the plateau after approximately 15 Ma. 3) Monsoon climates have existed across southern Asia for the whole of the Cenozoic, and probably for a lot longer, but that they were of the kind generated by seasonal migrations of the Inter-tropical Convergence Zone. 4) The projection of the High Himalaya above the Tibetan Plateau at about 15 Ma coincides with the development of the modern South Asia Monsoon. 5) The East Asia monsoon became established in its present form about the same time as a consequence of topographic changes in northern Tibet and elsewhere in Asia, the loss of moisture sources in the Asian interior and the development of a strong winter Siberian high as global temperatures declined. 6) New radiometric dates of palaeontological finds point to southern Asia's high biodiversity originating in the Paleogene, not the Neogene.
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Affiliation(s)
- Robert A. Spicer
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan 666303, PR China
- School of Environment, Earth and Ecosystem Sciences, The Open University, MK7 6AA, UK
- School of Environment, Earth and Ecosystem Sciences, The Open University, MK7 6AA, UK.
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Harrison PJ, Piontkovski S, Al-Hashmi K. Understanding how physical-biological coupling influences harmful algal blooms, low oxygen and fish kills in the Sea of Oman and the Western Arabian Sea. Mar Pollut Bull 2017; 114:25-34. [PMID: 27847169 DOI: 10.1016/j.marpolbul.2016.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/21/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Abstract
In the last decade, green Noctiluca scintillans with its symbiont and other dinoflagellates such as Cochlodinium polykrikoides, Prorocentrum micans and Scrippsiella trochoidea have become the dominant HABs, partially replacing the previously dominant diatoms and red Noctiluca scintillans, especially during the northeast monsoon. Fish kills in the Sea of Oman are linked to a slow seasonal decline in oxygen concentration from January to November, probably due to the decomposition of a series of algal blooms and the deep, low oxygen waters periodically impinging the Omani shelf. In the western Arabian Sea, cyclonic eddies upwell low oxygen, nutrient-rich water and the subsequent algal bloom decays and lowers the oxygen further and leads to fish kills. Warming of the surface waters by 1.2°C over the last 5 decades has increased stratification and resulted in a shoaling of the oxycline. This has increased the probability and frequency of upwelling low oxygen water and subsequent fish kills.
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Affiliation(s)
- Paul J Harrison
- Dept. Earth & Ocean Sciences, Univ. British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Sergey Piontkovski
- College of Agriculture & Marine Science, Sultan Qaboos University, Al-Khod 123, Oman
| | - Khalid Al-Hashmi
- College of Agriculture & Marine Science, Sultan Qaboos University, Al-Khod 123, Oman
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