Global three-dimensional simulation of aerosol optical thickness distribution of various origins

Toshihiko Takemura, Hajime Okamoto, Yoshihiro Maruyama, Atusi Numaguti, Akiko Higurashi, Teruyuki Nakajima

Research output: Contribution to journalArticle

288 Citations (Scopus)

Abstract

A global three-dimensional model that can treat transportation of various species of aerosols in the atmosphere is developed using a framework of an atmospheric general circulation model (AGCM). Main aerosols in the troposphere, i.e., soil dust, carbonaceous (organic and black carbon), sulfate, and sea-salt aerosols, are introduced into this model. Prior to the model calculations the meteorological parameters are calculated by the AGCM with the nudging technique using reanalysis data. To evaluate aerosol effects on the climate system and to compare simulated results with observations, the optical thickness and Angstrom exponent are also calculated taking into account the size distribution and composition. The model results are validated by both measured surface aerosol concentrations and retrieved aerosol optical parameters from National Oceanic and Atmospheric Administration/Advanced Very High Resolution Radiometer. A general agreement is found between the simulated result and the observation globally and seasonally. One of the significant results is that the simulated relative contribution of anthropogenic carbonaceous aerosols to the total optical thickness is comparable to that of sulfate aerosols at midlatitudes of the Northern Hemisphere, which agrees with recent observations. This result leads to a conclusion that the radiative effect evaluation of aerosols on the climate system is necessary to be modified because optical properties of carbonaceous aerosols are different from those of sulfate aerosols. The other finding is that the seasonal shift off the west coast of North Africa observed by satellites, i.e., the latitude of the maximum optical thickness moves seasonally, is also reproduced in consideration of a mixed state of soil dust and carbonaceous aerosols.

Original languageEnglish
Article number2000JD900265
Pages (from-to)17853-17873
Number of pages21
JournalJournal of Geophysical Research Atmospheres
Volume105
Issue numberD14
DOIs
Publication statusPublished - Jul 27 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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