Continuous observations of Asian dust and other aerosols by polarization lidars in China and Japan during ACE‐Asia

Abstract

[1] Continuous observations of aerosols in China and Japan were made by polarization lidars during March to May 2001, corresponding with the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) field campaign period. Lidars in Beijing, Nagasaki, and Tsukuba were continuously operated regardless of weather conditions. Scatterers in the atmosphere were categorized for all vertical profiles, and occurrence frequencies of dust, spherical aerosols, and clouds up to 6 km were calculated. The frequency of dust was highest in Beijing for the whole height range. There was a peak of dust occurrence near the ground in Nagasaki. Dust was frequently detected in the free troposphere in Tsukuba. The contributions of dust and spherical aerosols to the total backscattering coefficient were estimated from the depolarization ratio with the assumption of the external mixture of both kinds of aerosols. Vertical profiles of backscattering by dust and by spherical aerosols represented the different characteristics of these aerosols. The monthly averaged backscattering coefficients by dust near the surface were 0.003/km/sr in Beijing, 0.001-0.002/km/sr in Nagasaki, and 0.0006/km/sr in Tsukuba. The backscattering coefficients by spherical aerosols near the surface were 0.002-0.004/km/sr at all three observatories. We compared the derived backscattering coefficients with aerosol mass concentrations calculated by a numerical model, Chemical Weather Forecasting System (CFORS). CFORS reproduced well the vertical structures of the tall dust events and the enhancements of spherical aerosols throughout the observation period. A specific dust event on 16-19 May 2001 was analyzed by using five lidars in Japan, and its fine structure is described.

Separation of the optical and mass features of particle components in different aerosol mixtures by using POLIPHON retrievals in synergy with continuous polarized Micro-Pulse Lidar (P-MPL) measurements

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Exacerbation of daily cough and allergic symptoms in adult patients with chronic cough by Asian dust: A hospital-based study in Kanazawa

“…Asian dust period was estimated by the dust extinction coefficient, measured using a light detection and ranging (LIDAR) system, with a polarization analyzer that could distinguish between mineral dust, including Asian dust, and other spherical particles (Iwasaka et al, 2004;Shimizu et al, 2004;Sugimoto et al, 2011). We averaged 24 h data, obtained from the atmosphere 1 km above the ground at the Toyama observation station (Imizu City, Toyama Prefecture, Japan) which is approximately 40 km east of Kanazawa City.…”

Aerosols Monitoring Network to Create a Volcanic ASH Risk Management System in Argentina and Chile

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