Regional differences of light absorption properties of fine particulate
matter over the Tibetan Plateau: insights from HR-ToF-AMS and
Aethalometer measurements
Chongshui Gong
Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province, Key Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province, Key Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Institute of Arid Meteorology, China Meteorological Administration
Author ProfileXuying Sun
Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province, Key Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province, Key Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Institute of Arid Meteorology, China Meteorological Administration
Author ProfileHaolin Du
Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province, Key Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province, Key Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Institute of Arid Meteorology, China Meteorological Administration
Author ProfileAbstract
Tibetan Plateau (TP) has aroused widely scientific concerns in recent
decades owning to its important effects on regional climatic and
cryospheric changes, hydrological cycle, and environments. However, our
understandings on the chemical and optical properties of aerosols are
still limited at those regions. In this study, regional difference of
aerosol light absorption properties were explored at three remote TP
sites, including Qomolangma Station (QOMS) in the southern TP, Nam Co
Station (NamCo) in the central TP, and Waliguan Observatory in the
northeastern TP. Although aerosol mass concentration at QOMS was less
than half of that at Waliguan, the light absorption coefficient at QOMS
was nearly 5 time higher than that at Waliguan, mainly as a result of
the high contributions of light-absorbing carbonaceous aerosols in the
southern TP from the long-range transported biomass burning emissions of
South Asia. An improved method was used to derive the near-realistic
absorption Ångström exponent for pure black carbon (BC) particles. BC
dominated the light absorption at all wavelengths, whereas brown carbon
(BrC) contributed more than 30% of the light absorption at 370 nm at
QOMS and ~ 20% at Waliguan and NamCo. The major
contributor to BrC light absorption at QOMS was the biomass burning
related organic aerosol. Radiative transfer simulations also showed the
highest atmospheric radiative forcings at QOMS among the three
campaigns. The significant regional differences of aerosol light
absorption properties in the TP might be related tightly with the
different aerosol sources and chemical processes.