Simultaneous observations by sky radiometer and MAX-DOAS for characterization of biomass burning plumes in central Thailand in January-April 2016

Hitoshi Irie, Hossain Mohammed Syedul Hoque, Alessandro Damiani, Hiroshi Okamoto, Al Mashroor Fatmi, Pradeep Khatri, Tamio Takamura, Thanawat Jarupongsakul

研究成果: Article査読

16 被引用数 (Scopus)


The first intensive multicomponent ground-based remote-sensing observations by sky radiometer and multi-axis differential optical absorption spectroscopy (MAX-DOAS) were performed simultaneously at the SKYNET Phimai site located in central Thailand (15.18<span classCombining double low line"inline-formula">ĝ</span>&thinsp;N, 102.56<span classCombining double low line"inline-formula">ĝ</span>&thinsp;E) from January to April 2016. The period corresponds to the dry season associated with intense biomass burning (BB) activity around the site. The near-surface concentration of formaldehyde (HCHO) retrieved from MAX-DOAS was found to be a useful tracer for absorption aerosols from BB plumes, when BB was the dominant source of HCHO and absorption aerosols over other sources. As the HCHO concentration tripled from 3 to 9&thinsp;ppbv, the ratio of gaseous glyoxal to HCHO concentrations in daytime decreased from <span classCombining double low line"inline-formula">ĝ1/40.04</span> to <span classCombining double low line"inline-formula">ĝ1/40.03</span>, responding presumably to the increased contribution of volatile organic compound emissions from BB. In addition, clear increases in aerosol absorption optical depths (AAODs) retrieved from sky radiometer observations were seen with the HCHO enhancement. At a HCHO of 9&thinsp;ppbv, AAOD at a wavelength of 340&thinsp;nm reached as high as <span classCombining double low line"inline-formula"><math xmlnsCombining double low line"" idCombining double low line"M5" displayCombining double low line"inline" overflowCombining double low line"scroll" dspmathCombining double low line"mathml"><mrow><mo>ĝ1/4</mo><mn mathvariantCombining double low line"normal">0.15</mn><mo>±</mo><mn mathvariantCombining double low line"normal">0.03</mn></mrow></math><span><svg:svg xmlns:svgCombining double low line"" widthCombining double low line"66pt" heightCombining double low line"10pt" classCombining double low line"svg-formula" dspmathCombining double low line"mathimg" md5hashCombining double low line"c587c0c25d56ee4aca9b077feec6bef1"><svg:image xmlns:xlinkCombining double low line"" xlink:hrefCombining double low line"amt-12-599-2019-ie00001.svg" widthCombining double low line"66pt" heightCombining double low line"10pt" srcCombining double low line"amt-12-599-2019-ie00001.png"/></svg:svg></span></span>. The wavelength dependence of AAODs at 340-870&thinsp;nm was quantified by the absorption Ångström exponent (AAE), providing evidence for the presence of brown carbon aerosols at an AAE of <span classCombining double low line"inline-formula">1.5±0.2</span>. Thus, our multicomponent observations around central Thailand are expected to provide unique constraints for understanding physical-chemical-optical properties of BB plumes.

ジャーナルAtmospheric Measurement Techniques
出版ステータスPublished - 2019 1月 29

ASJC Scopus subject areas

  • 大気科学


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