Dust Aerosol Characteristics and Shortwave Radiative Impact at a Gobi Desert of Northwest China during the Spring of 2012

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Author(s)

    • BI Jianrong BI Jianrong
    • Key Laboratory for Semi-Arid Climate Change of the Ministry of Education and College of Atmospheric Sciences, Lanzhou University, Lanzhou, China
    • SHI Jinsen SHI Jinsen
    • Key Laboratory for Semi-Arid Climate Change of the Ministry of Education and College of Atmospheric Sciences, Lanzhou University, Lanzhou, China
    • XIE Yongkun [他] XIE Yongkun
    • Key Laboratory for Semi-Arid Climate Change of the Ministry of Education and College of Atmospheric Sciences, Lanzhou University, Lanzhou, China
    • LIU Yuzhi
    • Key Laboratory for Semi-Arid Climate Change of the Ministry of Education and College of Atmospheric Sciences, Lanzhou University, Lanzhou, China
    • TAKAMURA Tamio
    • Center for Environmental Remote Sensing (CEReS), Chiba University, Chiba, Japan
    • KHATRI Pradeep
    • Center for Environmental Remote Sensing (CEReS), Chiba University, Chiba, Japan

Abstract

 The Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) project initiated an intensive field experiment on dust aerosols in Dunhuang from April 1 to June 12, 2012. Using sky radiometer measurements and conducting model simulations, we investigated the dust aerosol characteristics and its shortwave radiative impact on the regional climate. The daily averaged optical features of the aerosols markedly varied throughout the study period. High aerosol loading and predominantly coarse particulates were observed in the spring of 2012 ascribed to the influence of prevalent dust storm. The single scattering albedo at 500 nm (SSA<sub>500</sub>) varied from 0.91 to 0.97 on dusty days and from 0.86 to 0.91 on dust-free days, indicating that the dust aerosols sourced from northwest China were not strongly absorbing. Surface radiation quantities estimated by the radiative transfer model excellently agreed with ground-based and satellite observations, with correlation coefficients exceeding 0.990 and mean differences ranging from -3.9 to 17.0 W m<sup>-2</sup>. The daily mean aerosol shortwave direct radiative forcing (ARF) values were largely negative at the surface (-79.4 to -3.2 W m<sup>-2</sup>) and moderately positive in the atmosphere (2.2-25.1 W m<sup>-2</sup>), indicating strong cooling at the surface and moderate atmospheric warming. The monthly averaged ARFEs (ARFs per unit aerosol optical depth at 500 nm (AOD500)) at the surface were (-73.9 ± 11.6) W m<sup>-2</sup>, (-67.4 ± 8.3) W m<sup>-2</sup>, and (-74.4 ± 5.4) W m<sup>-2</sup> in April, May, and June, respectively (overall average of (-70.8 ± 7.9) W m<sup>-2</sup>), comparable to previously obtained values in East Asia and India domains. The relations between the diurnal ARFs at the surface and top of the atmosphere (TOA) and the AOD500 indicate that aerosol composition remained relatively stable at Dunhuang during the spring of 2012. The ARF at the TOA was positive for SSA500 less than 0.85 or when the imaginary part at 500 nm exceeded 0.015.

Journal

  • Journal of the Meteorological Society of Japan. Ser. II

    Journal of the Meteorological Society of Japan. Ser. II 92A(0), 33-56, 2014

    Meteorological Society of Japan

Codes

  • NII Article ID (NAID)
    130004704180
  • NII NACSIS-CAT ID (NCID)
    AA00702524
  • Text Lang
    ENG
  • ISSN
    0026-1165
  • NDL Article ID
    025797811
  • NDL Call No.
    Z54-J645
  • Data Source
    NDL  J-STAGE 
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