Effects of sources, transport, and postdepositional processes on levoglucosan records in southeastern Tibetan glaciers

You, Cuihong; Yao, Tandong; Xu, Bin; Xu, Chao; Zhao, Huabiao; Song, Lili

doi:10.1002/2016jd024904

Cited by 30 publications

(34 citation statements)

References 51 publications

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“…Such melting‐refreezing cycles greatly help in accelerating the formation of the temperate glacier, which is commonly found in the SETP (Shi et al, ). As a result, when modeling the mass balance of glaciers in the SETP, the refreezing process is generally treated as an important item to improve the model accuracy (Yang et al, ; You et al, ; Zhang et al, ). These works all show that the refreezing process occurring in the SETP should be examined on its effect to modify the water isotopes.…”

Section: Discussionmentioning

confidence: 99%

Nonmonsoon Precipitation Dominates Groundwater Recharge Beneath a Monsoon‐Affected Glacier in Tibetan Plateau

Kong

Wang

et al. 2019

JGR Atmospheres

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Groundwater recharge is poorly understood beneath the glacier due to the complex sampling conditions, although it is sensitive to the global change. Here we carried out the sampling and isotopic analysis on groundwater, ice‐melt water, river, and precipitation through a hydrological year at the lowest glacier of Mingyong in Hengduan Mountains, Southeastern Tibetan Plateau. The precipitation during the monsoon seasons (Pm) are more depleted in heavy isotopes than precipitation during the nonmonsoon seasons (Pnm) due to the influence of monsoon. The ice‐melt water and groundwater points are both found located left above the local meteoric water line (δ2H = 8.0δ18O + 8.0) and form lines of δ2H = 6.3δ18O – 10.0 and δ2H = 4.2δ18O – 37.6, respectively. However, their mean isotopic values are both larger than the weighted annual mean of precipitation isotopes. All of the phenomena above points to the occurring of refreezing process after excluding the evaporation process. A theoretical model is built to confirm the refreezing process that causes the lower slope of ice‐melt water line. The groundwater line is explained as a mixing line with ice‐melt water and precipitation with contributions of 46 ± 22% and 54 ± 22%, respectively. For the precipitation contribution, we propose a plausible conceptual model that groundwater comes primarily from Pnm (41 ± 17%), and minor from Pm (13 ± 17%). In this context, it is equivalent to 87 ± 28% groundwater recharged by Pnm because the glacier is mainly accumulated from Pnm. The findings highlight the importance of the Pnm recharging groundwater even in the monsoon‐affected glacial regions.

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Section: Discussionmentioning

confidence: 99%

Nonmonsoon Precipitation Dominates Groundwater Recharge Beneath a Monsoon‐Affected Glacier in Tibetan Plateau

Kong

Wang

et al. 2019

JGR Atmospheres

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“…After light-absorbing aerosols, particularly BC, get deposited on the snow and glacier surface, they accelerate melting of snow fields and glaciers (Xu et al, 2009). Some BB tracers have been detected in the ice cores and snow samples from Tibetan Plateau (You et al, 2016;Gao et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Organic molecular tracers in the atmospheric aerosols from Lumbini, Nepal, in the northern Indo-Gangetic Plain: influence of biomass burning

et al. 2017

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Abstract. To better understand the characteristics of biomass burning in the northern Indo-Gangetic Plain (IGP), total suspended particles were collected in a rural site, Lumbini, Nepal, during April 2013 to March 2014 and analyzed for the biomass burning tracers (i.e., levoglucosan, mannosan, vanillic acid). The annual average concentration of levoglucosan was 734 ± 1043 ng m −3 with the maximum seasonal mean concentration during postmonsoon season (2206 ± 1753 ng m −3 ), followed by winter (1161 ± 1347 ng m −3 ), pre-monsoon (771 ± 524 ng m −3 ) and minimum concentration during monsoon season (212 ± 279 ng m −3 ). The other biomass burning tracers (mannosan, galactosan, p-hydroxybenzoic acid, vanillic acid, syringic acid and dehydroabietic acid) also showed the similar seasonal variations. There were good correlations among levoglucosan, organic carbon (OC) and elemental carbon (EC), indicating significant impact of biomass burning activities on carbonaceous aerosol loading throughout the year in Lumbini area. According to the characteristic ratios, levoglucosan / mannosan (lev / man) and syringic acid / vanillic acid (syr / van), we deduced that the high abundances of biomass burning products during nonmonsoon seasons were mainly caused by the burning of crop residues and hardwood while the softwood had less contribution. Based on the diagnostic tracer ratio (i.e., lev / OC), the OC derived from biomass burning constituted large fraction of total OC, especially during post-monsoon season. By analyzing the MODIS fire spot product and 5-day airmass back trajectories, we further demonstrated that organic aerosol composition was not only related to the local agricultural activities and residential biomass usage but also impacted by the regional emissions. During the post-monsoon season, the emissions from rice residue burning in western India and eastern Pakistan could impact particulate air pollution in Lumbini and surrounding regions in southern Nepal. Therefore, our finding is meaningful and has a great importance for adopting the appropriate mitigation measures, not only at the local level but also by involving different regions and nations, to reduce the biomass burning emissions in the broader IGP region nations.

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“…On the other hand, moisture carried by the westerlies can be substantially intercepted due to physical blocking by the very high mountains (e.g., the Pamir Plateau) along the transport pathways and the associated formation of precipitation on the windward slope (Tian et al, ). LEV, a water‐soluble component (Simoneit et al, ), can be effectively scavenged by wet deposition (You, Xu, et al, ; You, Yao, et al, ; You & Xu, ). Therefore, LEV released from West Asia and regions further away (e.g., Eastern Europe) could be substantially influenced by wet deposition during its long‐range transport.…”

Section: Resultsmentioning

confidence: 99%

“…Fire smoke can be uplifted to the free troposphere and can sometimes even penetrate the lower stratosphere under strong thermal convection (Vadrevu et al, 2012;Xu et al, 2015), from where it is then transported and ultimately deposited on high-altitude TP glaciers . TP glaciers act as natural archives of fire emissions for neighboring regions You, Yao, et al, 2016). Levoglucosan (LEV), a specific biomarker for fire emissions (Simoneit et al, 2004;You & Xu, 2018), has been widely detected in TP glacier snow and ice You, Yao, et al, 2016;You et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…TP glaciers act as natural archives of fire emissions for neighboring regions You, Yao, et al, 2016). Levoglucosan (LEV), a specific biomarker for fire emissions (Simoneit et al, 2004;You & Xu, 2018), has been widely detected in TP glacier snow and ice You, Yao, et al, 2016;You et al, 2017). Although transport and postdepositional processes can affect the temporal distribution of LEV in ice layers You, Yao, et al, 2016;You et al, 2017) considered to be the dominant factor influencing LEV records at least from seasonal to annual timescales (You, Yao, et al, 2016;You & Xu, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Recent Increases in Wildfires in the Himalayas and Surrounding Regions Detected in Central Tibetan Ice Core Records

You

Yao

2018

JGR Atmospheres

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Changes in fire activity across regions around the Tibetan Plateau are poorly understood, especially under the recent warming and drying trends. In this work, we report records of the specific fire tracer levoglucosan in a central Tibetan ice core, indicating a rapid increase in wildfires across the Himalayas and surroundings at the beginning of the 21st century. The climate system, especially precipitation changes, modulates the annual variability of wildfires in regions around the Tibetan Plateau. Decreasing premonsoon precipitation has prolonged the dry seasons across Himalayan regions affected by the Indian summer monsoon; meanwhile, increasing precipitation over the arid and semiarid Indus River Plain promotes plant growth and thereby increases biofuel availability. These trends have therefore induced increased frequencies of strong wildfires in the Himalayas and surroundings. Increasing strong wildfire events can potentially enhance black carbon deposits on Himalayan glaciers, which would impact glacial melting during the premonsoon wildfire seasons in the near future.

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Effects of sources, transport, and postdepositional processes on levoglucosan records in southeastern Tibetan glaciers

Cited by 30 publications

References 51 publications

Nonmonsoon Precipitation Dominates Groundwater Recharge Beneath a Monsoon‐Affected Glacier in Tibetan Plateau

Nonmonsoon Precipitation Dominates Groundwater Recharge Beneath a Monsoon‐Affected Glacier in Tibetan Plateau

Organic molecular tracers in the atmospheric aerosols from Lumbini, Nepal, in the northern Indo-Gangetic Plain: influence of biomass burning

Recent Increases in Wildfires in the Himalayas and Surrounding Regions Detected in Central Tibetan Ice Core Records

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