Size distribution of carbonaceous aerosols at a high-altitude site on the central Tibetan Plateau (Nam Co Station, 4730ma.s.l.)

2015 ◽  
Vol 153 ◽  
pp. 155-164 ◽  
Author(s):  
Xin Wan ◽  
Shichang Kang ◽  
Yuesi Wang ◽  
Jinyuan Xin ◽  
Bin Liu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
High Altitude ◽  
Size Distribution ◽  
Carbonaceous Aerosols ◽  
Nam Co ◽  
Central Tibetan Plateau

scholarly journals Air moisture signals in a stable oxygen isotope chronology of dwarf shrubs from the central Tibetan Plateau

2019 ◽  
Vol 124 (1) ◽  
pp. 53-64
Author(s):  
Jakob Wernicke ◽  
Georg Stark ◽  
Lily Wang ◽  
Jussi Grießinger ◽  
Achim Bräuning
Keyword(s):  
Tibetan Plateau ◽  
Tree Ring ◽  
Growth Ring ◽  
Asian Summer Monsoon ◽  
Monsoon Circulation ◽  
Nam Co ◽  
Climate Signal ◽  
Dwarf Shrubs ◽  
Central Tibetan Plateau ◽  
Annual Growth Rings

Abstract Background and Aims Annually resolved biological climate proxies beyond the altitudinal and latitudinal distribution limit of trees are rare. In such regions, several studies have demonstrated that annual growth rings of dwarf shrubs are suitable proxies for palaeoclimatic investigations. In High Asia, the pioneer work of Liang et al. (Liang E, Lu X, Ren P, Li X, Zhu L, Eckstein D, 2012. Annual increments of juniper dwarf shrubs above the tree line on the central Tibetan Plateau: a useful climatic proxy. Annals of Botany109: 721–728) confirmed the suitability of shrub growth-ring chronologies for palaeoclimatic research. This study presents the first sensitivity study of an annually resolved δ18O time series inferred from Wilson juniper (Juniperus pingii var. wilsonii) from the northern shoreline of lake Nam Co (Tibetan Plateau). Methods Based on five individual dwarf shrub discs, a statistically reliable δ18O chronology covering the period 1957–2009 was achieved (expressed population signal = 0.80). Spearman’s correlation analysis between the δ18O chronology and climate variables from different sources was applied. In a first step, the suitability of various climate data was evaluated. Key Results Examinations of climate–proxy relationships revealed significant negative correlations between the δ18O shrub chronology and summer season moisture variability of the previous and current year. In particular, relative humidity of the previous and current vegetation period significantly determined the proxy variability (ρ = −0.48, P < 0.01). Furthermore, the δ18O variability of the developed shrub chronology significantly coincided with a nearby tree-ring δ18O chronology of the same genus (r = 0.62, P < 0.01). Conclusions The δ18O shrub chronology reliably recorded humidity variations in the Nam Co region. The chronology was significantly correlated with a nearby moisture-sensitive tree-ring δ18O chronology, indicating a common climate signal in the two chronologies. This climate signal was likely determined by moisture variations of the Asian summer monsoon. Local climate effects were superimposed on the supra-regional climate signature of the monsoon circulation. Opposing δ18O values between the two chronologies were interpreted as plant-physiological differences during isotopic fractionation processes.

Monsoonal forcing of Holocene paleoenvironmental change on the central Tibetan Plateau inferred using a sediment record from Lake Nam Co (Xizang, China)

2013 ◽  
Vol 51 (2) ◽  
pp. 253-266 ◽  
Author(s):  
Stefan Doberschütz ◽  
Peter Frenzel ◽  
Torsten Haberzettl ◽  
Thomas Kasper ◽  
Junbo Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Sediment Record ◽  
Nam Co ◽  
Paleoenvironmental Change ◽  
Central Tibetan Plateau ◽  
Lake Nam Co

Quantifying evaporation and its decadal change for Lake Nam Co, central Tibetan Plateau

2016 ◽  
Vol 121 (13) ◽  
pp. 7578-7591 ◽  
Author(s):  
◽  
Kun Yang ◽  
Junbo Wang ◽  
Yanbin Lei ◽  
Yingying Chen ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Decadal Change ◽  
Nam Co ◽  
Central Tibetan Plateau ◽  
Lake Nam Co

scholarly journals Size-Segregated Characteristics of Carbonaceous Aerosols during the Monsoon and Non-Monsoon Seasons in Lhasa in the Tibetan Plateau

Atmosphere ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 157 ◽  
Author(s):  
Nannan Wei ◽  
Chulei Ma ◽  
Junwen Liu ◽  
Guanghua Wang ◽  
Wei Liu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Organic Carbon ◽  
Size Distribution ◽  
Fossil Fuels ◽  
Monsoon Season ◽  
Water Soluble ◽  
Atmospheric Particulate Matter ◽  
The Tibetan Plateau ◽  
Carbonaceous Aerosols ◽  
Different Diameters

In this paper, we intensively collected atmospheric particulate matter (PM) with different diameters (size ranges: <0.49, 0.49–0.95, 0.95–1.5, 1.5–3.0, 3.0–7.2, and >7.2 μm) in Lhasa during the monsoon and non-monsoon seasons. The results clearly showed that the concentrations of PM, organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC) during the non-monsoon season were much higher than the concentrations during the monsoon season. During the monsoon season, a bimodal size distribution of the OC and WSOC, which were at <0.49 μm and >7.2 μm, respectively, and a unimodal size distribution at <0.49 μm for the EC were observed. However, during the non-monsoon season, there was a trimodal size distribution of the OC and WSOC (<0.49 μm, 1.5–3.0 μm, and >7.2 μm), and a unimodal size distribution of the EC (<0.49 μm). Possible sources of the carbonaceous components were revealed by combining the particle size distribution and the correlation analysis. OC, EC, and WSOC were likely from the photochemical transformation of biogenic and anthropogenic VOC, and the incomplete combustion of biomass burning and fossil fuels at <0.49 μm, whilst they were also likely to be from various types of dust and biogenic aerosols at >7.2 μm. OC and WSOC at 1.5–3.0 μm were likely to have been from the burning of yak dung and photochemical formation. The above results may draw attention in the public and scientific communities to the issues of air quality in the Tibetan Plateau.

scholarly journals Particle number size distribution and new particle formation under the influence of biomass burning at a high altitude background site at Mt. Yulong (3410 m), China

2018 ◽  
Vol 18 (21) ◽  
pp. 15687-15703 ◽  
Author(s):  
Dongjie Shang ◽  
Min Hu ◽  
Jing Zheng ◽  
Yanhong Qin ◽  
Zhuofei Du ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
High Altitude ◽  
Size Distribution ◽  
Biomass Burning ◽  
Particle Number ◽  
Global Climate ◽  
Particle Formation ◽  
The Tibetan Plateau ◽  
Upper Troposphere ◽  
Number Size Distribution

Abstract. Biomass burning (BB) activities have a great impact on the particle number size distribution (PNSD) in the upper troposphere of the Tibetan Plateau, which could affect regional and global climate. An intensive campaign focused on the measurement of the PNSD, gaseous pollutants, and meteorological parameters was conducted at Mt. Yulong, a high-altitude site (3410 m a.s.l.) on the southeastern Tibetan Plateau during the pre-monsoon season (22 March to 15 April). During this period, intensive BB activities in southern Asia were detected by fire maps. The long-range transport of BB pollutants can increase the accumulation mode particles in the background atmosphere at Mt. Yulong. As a consequence, the cloud condensation nuclei (CCN) concentration was found to be 2–8 times higher during BB periods than during clean periods. Apart from BB, variations of the planet boundary layer (PBL) and new particle formation (NPF) were other factors that influenced the PNSD. However, only three NPF events (with a frequency of 14 %) were observed at Mt. Yulong. The occurrence of NPF events during clean episodes corresponded to an elevated PBL or transported BB pollutants. Due to the lack of condensable vapors including sulfuric acid and organic compounds, the newly formed particles were not able to grow to CCN size. Our study emphasizes the influences of BB on the aerosol and CCN concentration in the atmosphere of the Tibetan Plateau. These results also have the potential to improve our understanding of the variation of the particle concentration in the upper troposphere, and provide information for regional and global climate models.

scholarly journals Multi-year monitoring of atmospheric total gaseous mercury at a remote high-altitude site (Nam Co, 4730 m a.s.l.) in the inland Tibetan Plateau region

2018 ◽  
Vol 18 (14) ◽  
pp. 10557-10574 ◽  
Author(s):  
Xiufeng Yin ◽  
Shichang Kang ◽  
Benjamin de Foy ◽  
Yaoming Ma ◽  
Yindong Tong ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
High Altitude ◽  
Atmospheric Mercury ◽  
Atmospheric Environment ◽  
Daily Maximum ◽  
Total Gaseous Mercury ◽  
Nam Co ◽  
Gangetic Plain ◽  
Potential Source ◽  
Gaseous Mercury

Abstract. Total gaseous mercury (TGM) concentrations were continuously measured at Nam Co Station, a remote high-altitude site (4730 m a.s.l.), on the inland Tibetan Plateau, China, from January 2012 to October 2014 using a Tekran 2537B instrument. The mean concentration of TGM during the entire monitoring period was 1.33±0.24 ng m−3 (mean ± standard deviation), ranking it as the lowest value among all continuous TGM measurements reported in China; it was also lower than most of sites in the Northern Hemisphere. This indicated the pristine atmospheric environment on the inland Tibetan Plateau. Long-term TGM at the Nam Co Station exhibited a slight decrease especially for summer seasons. The seasonal variation of TGM was characterized by higher concentrations during warm seasons and lower concentrations during cold seasons, decreasing in the following order: summer (1.50±0.20 ng m−3) > spring (1.28±0.20 ng m−3) > autumn (1.22±0.17 ng m−3) > winter (1.14±0.18 ng m−3). Diurnal variations of TGM exhibited uniform patterns in different seasons: the daily maximum was reached in the morning (around 2–4 h after sunrise), followed by a decrease until sunset and a subsequent buildup at night, especially in the summer and the spring. Regional surface reemission and vertical mixing were two major contributors to the temporal variations of TGM while long-range transported atmospheric mercury promoted elevated TGM during warm seasons. Results of multiple linear regression (MLR) revealed that humidity and temperature were the principal covariates of TGM. Potential source contribution function (PSCF) and FLEXible PARTicle dispersion model (WRF-FLEXPART) results indicated that the likely high potential source regions of TGM to Nam Co were central and eastern areas of the Indo-Gangetic Plain (IGP) during the measurement period with high biomass burning and anthropogenic emissions. The seasonality of TGM at Nam Co was in phase with the Indian monsoon index, implying the Indian summer monsoon as an important driver for the transboundary transport of air pollution onto the inland Tibetan Plateau. Our results provided an atmospheric mercury baseline on the remote inland Tibetan Plateau and serve as new constraint for the assessment of Asian mercury emission and pollution.

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