title: Concentration, sources, and flux of dissolved organic carbon of precipitation at Lhasa city, the Tibetan Plateau.
abstract: Dissolved organic carbon (DOC) plays an important role in the climate system, but few data are available on the Tibetan Plateau (TP). In this study, 89 precipitation samples were collected at Lhasa, the largest city of southern Tibet, from March to December 2013. The average concentration and wet deposition flux of DOC was 1.10 mg C L(-1) and 0.63 g C m(-2) year(-1), respectively. Seasonally, low DOC concentration and high flux appeared during the monsoon period, which were in line with heavy precipitation amount, reflecting dilution effect of precipitation for the DOC. Compared to other regions, the values of Lhasa were lower than those of large cities (e.g., Beijing and Seoul) mainly because of less air pollution of Lhasa. The principal component analysis (PCA) of DOC and ions (Ca(2+), Mg(2+), Na(+), K(+), NH4 (+), Cl(-), NO3 (-), and SO4 (2-)) showed that DOC of Lhasa was derived mainly from the natural sources, followed by anthropogenic burning activities. Furthermore, △(14)C value of DOC indicated that fossil fuel combustion contributed around 28 % of the rainwater DOC of Lhasa, indicating that the atmosphere of Lhasa has been influenced by emission from fossil fuel combustion or high-temperature industrial processes.
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing, 100101, China. lichaoliuli@126.com.|CAS Center for Excellence in Tibetan Plateau Earth Sciences, CAS, Beijing, 100101, China. lichaoliuli@126.com.
authors.forename: Chaoliu
authors.initials: C
authors.lastname: Li
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute (CAS), Lanzhou, 730000, China.|Graduate University of Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Fangping
authors.initials: F
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute (CAS), Lanzhou, 730000, China.|CAS Center for Excellence in Tibetan Plateau Earth Sciences, CAS, Beijing, 100101, China.
authors.forename: Shichang
authors.initials: S
authors.lastname: Kang
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing, 100101, China.|Graduate University of Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Chen
authors.affiliation: Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, FIN-50130, Mikkeli, Finland.
authors.forename: Bin
authors.initials: B
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute (CAS), Lanzhou, 730000, China.|Graduate University of Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Zhaofu
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, FIN-50130, Mikkeli, Finland.
authors.forename: Mika
authors.initials: M
authors.lastname: Sillanpää
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D064751:Ammonium Compounds / Q000032:analysis; D002244:Carbon / Q000032:analysis*; D002712:Chlorides / Q000032:analysis; D002947:Cities; D004784:Environmental Monitoring; D005579:Fossil Fuels; D008670:Metals / Q000032:analysis; D009566:Nitrates / Q000032:analysis; D011891:Rain / Q000737:chemistry; D013431:Sulfates / Q000032:analysis; D018609:Tibet
chemical_list: D000393:Air Pollutants; D064751:Ammonium Compounds; D002712:Chlorides; D005579:Fossil Fuels; D008670:Metals; D009566:Nitrates; D013431:Sulfates; D002244:Carbon
keywords: Dissolved organic carbon; Pollutants; The Tibetan Plateau; Urban area; Wet deposition