Aerosol sampling and measurement by ACE Asia group

Atmospheric aerosol particles affect the Earth's radiative balance directly by scattering or absorbing light, and indirectly by acting as cloud condensation nuclei (CCN), thereby influencing the albedo and life-time of clouds. The natural aerosol has been substantially perturbed by anthropogenic activities, particularly by increases of sulfates, nitrates, organic condensates, soot, and soil dust. The present day global mean radiative forcing due to anthropogenic aerosol particles is estimated to be between - 0.3 and -3.5 Wm-2, which must be compared with the present day forcing by greenhouse gases of between +2.0 and +2.8 Wm-2 (IPCC, 1995).

Although aerosol particles have this potential climatic importance, they are poorly characterized in global climate models. This is a result of a lack of both comprehensive global data and a clear understanding of the processes linking aerosol particles, aerosol precursor emissions, and radiative effects. At this time, tropospheric aerosols pose the largest uncertainty in model calculations of the climate forcing due to man-made changes in the composition of the atmosphere. Clearly there is an urgent need to quantify the processes controlling the natural and anthropogenic aerosol, and to define and minimize the uncertainties in the calculated climate forcings. Among the largest sources of uncertainty is the climate forcing by Asian aerosols.

The Aerosol Characterization Experiments (ACE) , which are sponsored by the International Global Atmospheric Chemistry Program (IGAC), are envisioned as a series of international field studies aimed at understanding the combined chemical and physical processes that control the evolution of those aerosol properties that are relevant to radiative forcing and climate. The ultimate goal of this series of studies is to provide the necessary data to incorporate aerosols into global climate models and to reduce the overall uncertainty in the climate forcing by aerosols.

The strategy of ACE is to investigate the multiphase atmospheric system in key areas of the globe. ACE-1, conducted in late 1995, was aimed at the minimally polluted marine troposphere in the Southern Ocean near Tasmania. TARFOX, conducted in June of 1996, studied continental aerosol off the eastern coast of North America. ACE-2, to be conducted in June of 1997, will focus on anthropogenic aerosols from the European continent and desert dust from the African continent as they move over the North Atlantic Ocean. Another European ACE experiment is being planned for 1999 or 2000, in the heavily polluted regions of Eastern Europe.

ACE Asia, of which intensive observations are planned in spring 2001 and 2003, will focus on the outflow of both desert dust and anthropogenic aerosol from Eastern Asia to the Pacific. The goal of ACE Asia is to determine and understand the properties and controlling factors of the aerosol in the anthropogenically modified atmosphere of Eastern Asian and the Northwest Pacific and to assess their relevance for radiative forcing.

R/V Mirai is elected as the platform of Japanese shipbord observation. The MR00-K04 cruise was regarded as the pre-ACE Asia cruise by all Japan researchers. PIs and on board members of pre-ACE Asia group were shown in Tables 1and Tables 2. The MR01-K02 cruise was regarded as the ACE Asia cruise. PIs and on board members of ACE Asia group were shown in Tables 3 and Tables 4.

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