An overview of ACE‐Asia: Strategies for quantifying the relationships between Asian aerosols and their climatic impacts

Abstract

[1] The International Global Atmospheric Chemistry Program (IGAC) has conducted a series of Aerosol Characterization Experiments (ACE) that integrate in situ measurements, satellite observations, and models to reduce the uncertainty in calculations of the climate forcing due to aerosol particles. ACE-Asia, the fourth in this series of experiments, consisted of two focused components: (1) An intensive field study that sought to quantify the spatial and vertical distribution of aerosol concentrations and properties, the processes controlling their formation, evolution, and fate, and the column-integrated radiative effect of the aerosol (late March through May 2001). (2) A longer-term network of ground stations that used in situ and column-integrated measurements to quantify the chemical, physical, and optical properties of aerosols in the ACE-Asia study area and to assess their spatial and temporal (seasonal and interannual) variability (2000)(2001)(2002)(2003). The approach of the ACE-Asia science team was to make simultaneous measurements of aerosol chemical, physical, and optical properties and their radiative impacts in a variety of air masses, often coordinated with satellite overpasses. Three aircraft, two research ships, a network of lidars, and many surface sites gathered data on Asian aerosols. Chemical transport models (CTMs) were integrated into the program from the start, being used in a forecast mode during the intensive observation period to identify promising areas for airborne and ship observations and then later as tools for integrating observations. The testing and improvement of a wide range of aerosol models (including microphysical, radiative transfer, CTM, and global climate models) was one important way in which we assessed our understanding of the properties and controlling processes of Asian aerosols. We describe here the scientific goals and objectives of the ACE-Asia experiment, its observational strategies, the types of observations made by the mobile platforms and stationary sites, the models that will integrate our understanding of the climatic effect of aerosol particles, and the types of data that have been generated. Eight scientific questions focus the discussion. The intensive observations took place during a season of unusually heavy dust, so we have a large suite of observations of dust and its interaction with air pollutants. Further information about ACE-Asia can be found on the project Web site at http://saga.pmel.noaa.gov/aceasia/.

Diurnal and temporal variations of water-soluble dicarboxylic acids and related compounds in aerosols from the northern vicinity of Beijing: Implication for photochemical aging during atmospheric transport

“…Atmospheric particles have an influence on the global climate system, providing an adverse effect on human health and visibility (Huebert et al, 2003;Kaufman et al, 2002;Menon et al, 2002;Richter et al, 2005). Severe droughts in northern China and enhanced summer floods in southern China may be associated with the anthropogenic atmospheric particles that modify the regional air circulation (Menon et al, 2002).…”

Trace gas and aerosol interactions in the fully coupled model of aerosol‐chemistry‐climate ECHAM5‐HAMMOZ: 1. Model description and insights from the spring 2001 TRACE‐P experiment

“…The model underestimate in the upper troposphere, clearly visible in Figures 7 and 8, may be due to several reasons, including (1) too strong wet deposition rates that prevent aerosols from reaching the upper levels, (2) too low surface emissions or (3) a missing in situ source of aerosols. Heald et al [2005], for instance, compared organic carbon concentrations simulated by a global chemical transport model to concentrations measured during the aircraft campaign ACE-Asia [Huebert et al, 2003] (i.e., in a region similar to that sampled during the TRACE-P experiment) and found that the measured values were 10-100 times higher than the simulated concentrations even if their simulation included a parameterization for SOA formation from biogenic trace gases. They suggest that a large source of SOA is missing in the free troposphere from the oxidation of long-lived volatile organic compounds present in continental outflow.…”

Low molecular weight (C1–C10) monocarboxylic acids, dissolved organic carbon and major inorganic ions in alpine snow pit sequence from a high mountain site, central Japan

“…Although organic acids have been studied in snow samples from North America and Europe (e.g., Kawamura et al, 2000;Legrand et al, 2003), there are no reports on homologous series of low molecular weight monocarboxylic acids in Asian region, in which anthropogenic emissions of organics are significant due to the enhanced economic growth in China (Huebert et al, 2003). The western rim of the North Pacific where Japanese Islands exist is located under the pathway of the atmospheric transport of pollutants from East Asia by westerly winds.…”