Atmospheric Composition Research Team

We welcome post-doctoral researchers from Japan or from overseas especially on
(1) field measurements or laboratory studies (heterogeneous chemistry) of OH and HO2 radicals
(2) MAX-DOAS network measurements in east Asia and Russia.

Please contact us for more information. Application for JSPS postdoctral fellowship (see the site) is encouraged.

Address

Frontier Research Bldg, 2F, JAMSTEC Yokohama campus,
3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, JAPAN

Air quality in East Asia has been affected by rapid development in the region. Ozone and aerosol particles can have serious impact on human health and biosphere. Their influence on the climate/weather is also important, because tropospheric ozone and black carbon induce heating and other relatively transparent particles contribute to cooling. The effect is non-uniform over the region, because of their short lifetimes (less than 2 weeks or 1 month)in the atmosphere. Our activities are focused on field observations, satellite data analysis, and laboratory studies to better understand the transformation and transport processes important to determine the geographical and tempral variations of the trace species in the atmosphere.

1. In-situ field observations: O3, aerosols, and related parameters

We perform intensive field campaigns/long-term observations at selected sites in East Asia. We observe concentrations of ozone, its precursors, and aerosol chemical species, as well as aerosol optical parameters. We evaluate model simulations (and thus emission inventories) and perform process analyses for the causes of the variability (e.g., transportation and transformation, ozone production rate and regimes). Aerosol mass closure and chemical-physical-optical point closure are also our focus. Recent major field studies took place at Fukue Island, west of Japan, and at Rudong in China. We also took part in summertime intensive observations at the summit of Mt. Fuji for 2008-2010. We collaborate with Professors Zifa Wang and Meigen Zhang (IAP/CAS), NIES, NPO Valid Utilization of Mt. Fuji Weather Station, and other universities/research institutes.

further information for 1

• ACP - Special Issue: The Mount Tai Experiment 2006 (MTX2006): regional ozone photochemistry and aerosol studies in Central East China.
• Kanaya et al., Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006, Atmos. Chem. Phys., 8, 7637-7649 (2008).
• Kanaya et al., Rates and regimes of photochemical ozone production over Central East China in June 2006: a box model analysis using comprehensive measurements of ozone precursors, Atmos. Chem. Phys., 9, 7711-7723 (2009).

2. Field remote sensing observations: MAX-DOAS network

We developed light-weighted MAX-DOAS instrument, which observe UV/vis spectra of scattered sunlight at selected elevation angles from ground to retrieve vertical profiles/column amount of NO2 and aerosols. The instruments are distributed to form a Japan/Korea/China/Russia monitoring network. Shipborne observations are also started on JAMSTEC's Research Vessels. The main objectives are to validate satellite observations of tropospheric NO2 column densities and aerosol optical depth (AOD), to observe diurnal variations/vertical profiles beyond the capabilities of the current satellite sensors, and to validate chemical transport model simulations. This research is conducted under a GEOSS-related funding sponsored by MEXT (FY2006-2010). We collaborate with GIST (Gwangju, Korea), AIOFM/CAS (Hefei, China), IAP/RAS (Zvenigorod/Moscow, Russia), and IAO/RAS-SB (Tomsk, Russia).

further information for 2

• Irie et al., First retrieval of tropospheric aerosol profiles using MAX-DOAS and comparison with lidar and sky radiometer measurements, Atmos. Chem. Phys., 8, 341-350 (2008).
• Irie et al., Validation of OMI tropospheric NO2 column data using MAX-DOAS measurements deep inside the North China Plain in June 2006, Atmos. Chem. Phys, 8, 6577-6586 (2008).
• Takashima et al., Atmospheric aerosol variations at Okinawa Island in Japan observed by MAX-DOAS using a new cloud-screening method, J. Geophys. Res., 114, D18213, doi:10.1029/2009JD011939. (2009).

3. Satellite data analysis

We analyze satellite-based air quality data set in East Asia, to scale up the in-situ observations mentioned above. We also contribute to a new plan to observe air quality over East Asia from a geostationally satellite.

further information for 2 and 3

• Press release: Atmospheric NO2 levels in China Reach Record High in 2007 and 2008 - Continuous Increase Since 1996 May Be Affecting Air Quality in Japan -  (page in Japanese)
• Irie et al., Characterization of OMI Tropospheric NO2 Measurements in East Asia Based on a Robust Validation Comparison, SOLA, 5, 117-120 (2009)

4. Laboratory studies and development of new instruments

We also perform laboratory experiments to verify hypotheses brought back from field studies; for example, determination of uptake coefficients of HO2 radicals on various kinds of aerosol particles, which was hypothesized from lower-than-modeled HO2 concentrations observed at Rishiri Island. We also develop new instruments: e.g., detection of single aerosol particles containing certain types of organics by fluorescence measurements.

further information for 4

• Taketani et al., Kinetics of HO2 Uptake in Levoglucosan and Polystyrene Latex Particles, J. Phys. Chem. Lett. 1, 1701-1704, DOI: 10.1021/jz100478s (2010).
• Taketani et al., Kinetics of heterogeneous reaction of HO2 radical at ambient concentration levels with (NH4)2SO4 and NaCl aerosol particles, J. Phys. Chem. A, 112 (11), 2370 -2377, doi:10.1021/jp0769936 (2008).

The instruments that we operate in the field/laboratory are shown below.