AAS21-P01

Room:Convention Hall

Time:May 27 18:15-19:30

Coating of black carbon aerosols and increase of their light absorption coefficient observed in Tokyo
AOKI, Haruki1∗ ; KITA, Kazuyuki2 ; MOTEKI, Nobuhiro3 ; OHATA, Sho3 ; ADACHI, Kouji4 ;IGARASHI, Yasuhito4 ; KOIKE, Makoto3 ; KONDO, Yutaka3
1

Graduate School of Science and Engineering, Ibaraki University, 2 College of Science, Ibaraki University, 3 Graduate School of
Science, The University of Tokyo, 4 Meteorological Research InstituteBlack carbon (BC) aerosols can influence the climate due to the heating the atmosphere by their strong light absorption (direct
effect). Light absorption coefficient of BC is varied with their size, shape and mixing states. BC is often coated with otheraerosol component such as organics and sulfate, and the coating is supposed to cause the increase of light absorption coefficient(lens effect). Lens effect has still not fully understood because the coating material and amount in the real atmosphere have notunderstood quantitatively. Therefore it is important to observe change of light absorption coefficient of BC and their shape andmixing state simultaneously. Our group conducted intensive observation of various parameters of BC, including light absorption
coefficient and coating amount, in huge city, Tokyo. In this paper, variation of light absorption coefficient of BC in Tokyo and its
relation with BC coating is studied.
Intensive BC observation named as Black Carbon / Carbonaceous Aerosol Removal Experiment (BC-CARE) were conductedfrom July 28 to August 15 in 2014. The atmospheric BC was sampled and observed at the sixth floor (20m) in Tokyo University,
located central Tokyo city area. Light absorption coefficient was measured using the photoacoustic soot spectrometer (PASS).
Amplification factor (FA) by coating of BC was evaluated from the ratio of light absorption coefficient in the unheated sampled
air to that in the 300 ℃ heated air, where volatile coating materials were removed from BC. BC mass concentration and theratio of coating thickness with BC diameter (Dp/Dc) was measured using single-particle soot photometer (SP2) simultaneously.
During observation period, aerosol particle were regularly sampled and the BC size, shape and mixing states were observed using
a transmission electron microscope (TEM).
The significant increase in BC light absorption coefficient with the BC coating was measured on 29th July. Maximum increase
was about 80% in this period. In the early half of this period, FA and Dp/Dc values were increased correlatingly from about 1.0
to about 1.8. However, in the latter half of this period, FA values were gradually decreased although Dp/Dc values kept high.
Observation with TEM showed that many coating BC particles larger than 1µm in the early half of this period. In the latter half,
particle size of coated BC was generally less than 0.5µm. Because the measuring range of particle size of SP2 is less than 1µm
and PASS can measure BC about 1µm or more, the difference between the two period may be cause by the contribution of theselarger BC particles. However, both PASS and SP2 can measure BC particles less than 0.5µm, these results cannot fully explain
the observed difference in FA and Dp/Dc behavior.
Keywords: Black carbon, Light absorption coefficient, Lens effect, Electron microscope

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AAS21-P02

Room:Convention Hall

Time:May 27 18:15-19:30

Online Measurement of Aerosol Chemical Composition Classified by Black Carbon Mixing State using a LII-MSOZAWA, Yuya1∗ ; TAKEDA, Naoki2 ; KOIZUMI, Kazuhiro2 ; TAKEGAWA, Nobuyuki3
1

The University of Tokyo, 2 Fuji Electric, Co., Ltd., 3 Tokyo Metropolitan University

Aerosols have large influences on the radiation budget of the Earth’s atmosphere by scattering or absorbing solar visible radiation (direct effect) and by altering cloud microphysical properties (indirect effect) (IPCC, 2013). These effects can significantly
depend on the chemical composition and mixing state of aerosol particles. Specifically, the mixing state of sulfate, nitrate, andorganics with black carbon (BC) is a key parameter for estimating the aerosol direct and indirect effects.
We have developed a new method to measure aerosol chemical composition classified by the mixing state with BC by combining laser induced incandescence (LII) and mass spectrometric (MS) methods (LII-MS, Miyakawa et al., AST, 48, 853-863,
2014). The purpose of this study is to further evaluate the LII-MS in the laboratory and also to understand the temporal variationsof BC mixing state in a suburban area in Tokyo.
The LII-MS consists of a series of LII and MS. In the LII section, BC containing particles introduced into a near-infraredlaser cavity can be efficiently vaporized and incandescence signals from the BC particles are detected. The sample air is thenintroduced into the MS section by a tandem nozzle to measure the mass concentrations of sulfate and nitrate (Takegawa et al.,AST, 46, 428-443, 2012). The aerosol composition classified by the BC mixing state is obtained by alternatively switching on
and off the LII laser.
Several modifications of the LII-MS hardware and additional experiments have been performed compared to the previous
version presented by Miyakawa et al. (2014). First, the control electronics for switching the LII laser has been modified toachieve more stable operation. Second, the cycle of the LII laser on/off and zero-air modes has been modified to improve thequantification of the BC mixing state. Third, the performance of the tandem nozzle, which is one of the key components of the
LII-MS, has been tested in the laboratory to investigate the stability and reproducibility of the particle transport efficiency. Ambient measurements have been conducted at the Tokyo Metropolitan University to test the overall performance of the LII-MS and
to investigate the temporal variation of the BC mixing state in suburban air. Details of the laboratory experiments and ambient
measurements will be presented and discussed.
Keywords: Aerosol, BC mixing state, Laser-induced incandescence, Mass spectrometer

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AAS21-P03

Room:Convention Hall

Time:May 27 18:15-19:30

Single-particle measurement of iron-containing dust particles using a laser-induced incandescence technique
YOSHIDA, Atsushi1∗ ; MOTEKI, Nobuhiro1
1

Graduate School of Science, The University of Tokyo

1. Introduction
Two major light-absorbing ubiquitous in earth atmosphere, black carbon (BC) and mineral dust, contribute positive climate
forcing by absorbing solar radiation in atmosphere and by reducing albedo of snowpack. Light-absorption efficiency of mineral
dust has shown to be strongly correlated with iron-content [Moosmueller 2012]. Reliable data for concentration and microphysical properties (size distribution, mixing state, complex refractive index, etc.) of BC and iron-containing dust particles areimportant to provide a physical basis in climate simulations.
For statistical sampling and continual observations, we need a fast and real-time technique to measure concentrations and themicrophysical properties of these light-absorbing particles. In this study, we experimentally show that the laser-induced incandescence (LII) technique, which has been used only for BC measurement so far, is also effective for identifying and measuringiron-containing dust particles.
2. Laser-induced incandescence (LII)
We use the single-particle soot photometer (SP2, Droplet measurement technology) to measure laser-induced incandescenceand light-scattering signals for individual particles. In SP2, sample air containing aerosols are continually introduced into an
intra-cavity Nd:YAG laser beam with 1064 wavelength. Refractory light-absorbing particles with boiling higher than ∼3000K
emit thermal radiation detectable in visible wavelength. In SP2, thermal radiation is measured at two distinct wavelength bands,
the blue-band (300-500 nm) and the red-band (580-710 nm), to infer the spectra of incandescent light. As the spectra of thermalradiation shifts shorter wavelength as temperature increases, the blue-band to red-band signal ratio (color ratio) is a proxy ofboiling point of the incandescing particle.
3. Identification of incandescing particles
The probability distribution of measured color ratio for various laboratory samples and field dust samples are shown in Figure.
For laboratory sample, there are three distinct modes in color ratio distribution: iron and iron oxides (∼1.5), titanium (∼2.0),
and fullerene soot (∼2.6) (standard material of BC). Therefore, we can distinguish incandescent materials (iron, iron oxides,
titanium, BC) in a particle using the value of color ratio.
Figure also shows the result for two field samples: Iceland particle (provided by Dr. P. Dagsson-Waldhauserova, Universityof Iceland) and Taklimakan desert particle (provided by Dr. R. Tada (The University of Tokyo)). The color ratio distributions ofthese samples have two distinct modes with peaks around 1.5 and 2.6, corresponding to iron (and iron oxides) and fullerene soot,respectively. From the observed color ratio, the incandescing particles observed in the two field samples were identified as BC
and iron-containing particles.
4. Calibration for iron measurement by LII
We have experimentally determined the relationships between blue-band signal intensity and mass of pure iron particle. This
relationship was used as a calibration curve for estimating iron-content in field samples.
Keywords: aerosol, atmospheric chemistry

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AAS21-P03

Room:Convention Hall

Time:May 27 18:15-19:30

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AAS21-P04

Room:Convention Hall

Time:May 27 18:15-19:30

Development and preliminary evaluation of an aerodynamic lens for focusing nanoparticles
OTAKE, Hiroki1∗ ; TAKEGAWA, Nobuyuki1
1

Tokyo Metropolitan University

Aerosols have significant impacts on the radiation budget of the Earth’s atmosphere by direct and indirect effects. Chemicalcomposition of aerosol particles with diameters smaller than 100 nm (nanoparticles) is an important factor for understanding
the formation process of aerosols. However, measuring chemical composition of nanoparticles is challenging because of theirextremely low mass loadings in ambient air. Aerosol mass spectrometry coupled with an aerodynamic lens (ADL; Liu et al.,AST, 22, 293, 1995), which can efficiently deliver aerosol particles into vacuum, is a useful tool for online measurements ofaerosol composition. Although the concept of an aerodynamic lens for nanoparticles (nano-ADL) has been reported by previous
studies (e.g., Wang et al., IJMS, 258, 30, 2006), the application of nano-ADL to ambient measurements has not been established.
We have developed an improved nano-ADL based on the design of ADL for submicron particles (submicron-ADL) that has beenused for aerosol mass spectrometry.
Laboratory experiments were performed using a custom-made particle generation system consisting of saturation and condensation tubes for oleic acid vapor. Monodisperse particles generated by a differential mobility analyzer were introduced into thesubmicron or nano ADL.
The detection of particles was performed using a Faraday cup. The transmission efficiency and particle beam width were
measured using a movable knife-edge.
The submicron-ADL showed nearly 100% transmission efficiency for particles larger than 100 nm. On the other hand, thenano-ADL showed nearly 100% transmission efficiency at around 50 nm and decreased with increasing particle diameters, suggesting that the current design is favorable for the sampling of nanoparticles. The application of the nano-ADL to an aerosol
mass spectrometry system will be discussed in the presentation.
Keywords: Aerosol, Nano particle, Aerodynamic lens, Mass spectrometry

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AAS21-P05

Room:Convention Hall

Time:May 27 18:15-19:30

Evaluation of an online analysis method of nitrate aerosols using a particle trap laser desorption mass spectrometer
OIZUMI, Tomotaka1∗ ; OZAWA, Yuya2 ; TAKEGAWA, Nobuyuki1
1

Tokyo Metropolitan University, 2 The University of Tokyo

Aerosols play important roles in global air quality and climate change. Ammonium nitrate, which is generated via photochemical reaction of NOx, often contributes to a major fraction of fine particles in urban air. The gas-to-particle equilibrium reactionof ammonium nitrate exhibits strong temperature dependency near ambient temperatures, which often yields evaporative loss ofparticles during sampling.
We have developed a particle trap-laser desorption mass spectrometer (PT-LDMS) for online measurements of aerosol chemical compositions (Takegawa et al., AST, 46, 428, 2012). Factors affecting the quantification of nitrate aerosols, including, havenot been fully characterized. The purpose of this study is to evaluate the quantification of nitrate aerosols by the PT-LDMS in
the current configuration and also to investigate an optimal condition for ambient sampling.
Laboratory experiments were performed by generating monodisperse ammonium nitrate particles using an atomizer and differential mobility analyzer. The dependence of the sensitivity (defined as ion signals per collected nitrate mass) on the particle
trap temperature was measured by altering the temperature of the particle trap holder between 280 and 313 K. The dependence ofthe sensitivity on the time after particle collection until laser irradiation (exposure time) was also measured. In addition, effectsof the mixing state of nitrate particles on the sensitivity were evaluated by atomizing a mixed solution of ammonium nitrate andsulfate.

Preliminary results show that the sensitivity tended to decrease with increasing the exposure time for each temperature condition, which is likely due to evaporative loss of nitrate particles in the vacuum. On the other hand, the sensitivity did not exhibit
significant temperature dependency at least for the temperature conditions during the experiments.
Possible mechanisms affecting the loss of nitrate particles, along with the effects of the mixing state on the sensitivity, will bepresented and discussed.

Keywords: nitrate aerosols, online analysis method, mass spectrometer

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AAS21-P06

Room:Convention Hall

Time:May 27 18:15-19:30

Development of photovoltaic-driven atmospheric observation instrument Eco-MAXDOAS
KATO, Tomomichi1∗ ; IRIE, Hitoshi2
1Graduate School of Advanced Integration Science, Chiba University, 2 Center for Environmental Remote Sensing, Chiba University
Atmospheric aerosols are an important factor controlling the Earth’s climate. However, their complicated formation mechanisms and effects on climate are poorly understood. Under these circumstances, the MAX-DOAS technique that enables simultaneous measurements of aerosols and their gaseous precursors, such as nitrogen dioxide (NO2 ), has been developed by
Chiba University. The MAX-DOAS technique can derive the vertical distribution and column amount for aerosols and gases byutilizing the inversion analysis of scattered sunlight spectra measured at multiple viewing elevation angles. When MAX-DOAS
observations are made, the line of sight must be clear at all elevation angles selected for the observations. In addition, there is
the need for sufficient electric power, limiting the observation site. To solve these limitations, we developed the new instrument,
called Eco-MAXDOAS, using the photovoltaics as a power source. For this development, we removed a temperature controller
to reduce the power consumption. Instead, a shutter was introduced just before the entrance slit of the spectrometer. With thismodification, it was made possible to take dark count measurements more often than for the normal MAX-DOAS instrument byclosing the shutter between observations at different elevation angles. We tested the Eco-MAXDOAS and found that the spectrometer temperature changed by less than ±0.3 degrees for 3 min. interval of changing elevation angles. Using dark count dataobtained before and after a scattered sunlight observation was made, the SNR was estimated to be about 10000. This supportsthat analysis for a differential absorption as small as 10−4 (0.01%) is possible. In addition, we conducted continuous observations
using 30-W and 60-W solar panels. When the 30-W solar panel was used, the Eco-MAXDOAS terminated in few days. On
the other hand, using the 60-W solar panel prolonged the operation time period and the Eco-MAXDOAS worked continuously
for over full test observation period of two weeks under usual weather conditions in winter. In this presentation, we also assess
the performance for the Eco-MAXDOAS observation by comparing aerosol an NO2 data retrieved from Eco-MAXDOAS andMAX-DOAS observations.
Keywords: MAX-DOAS, solar power, aerosol, nitrogen dioxide

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AAS21-P07

Room:Convention Hall

Time:May 27 18:15-19:30

Measurement of stable isotope ratios of atmospheric carbon dioxide by wavelength modulation absorption spectroscopy with
KINDAICHI, Yusuke1∗ ; TONOKURA, Kenichi1
1

Graduate School of Frontier Science, Tokyo University

Since the industrial revolution, the concentration of carbon dioxide, a greenhouse gas is increasing every year, it has become acause of global warming. Carbon dioxide is released from various emission sources and is absorbed to different sinks. Carbon
dioxide is circulated among the atmosphere, hydrosphere, and geosphere. For suppression global warming, there is a need toaccurately grasp the emissions and removals of carbon dioxide between these reservoirs. Measurement of concentration andstable isotope ratio of carbon dioxide provide us useful information in order to elucidate the carbon cycle. Therefore, we focus
on the approach to use the stable isotope as an index. Carbon dioxide has stable isotopes, 12 CO2 , 13 CO2 , and 12 C18 O16 O, it is
known that these isotope ratios are different for each emission source.
As one of conventional measurement techniques of isotope ratios which has been used, there is isotope ratio mass spectrometry (IRMS) technique. Although this technique has a very high measurement precision (0.01-0.1 ‰), it cannot be measured
outside the laboratory because the device is a large. Therefore, a laser absorption spectroscopy in recent years has been attracting
attention. This technique is excellent in portability since the device can be made compact. Also, because suitable selection ofabsorption lines prevents interference from other species, the sample can be introduced directly to the device. Therefore, thedevice can be carried to the location where we want to measure the stable isotope ratio of carbon dioxide, it is possible to perform
real-time measurements at high time resolution.
In this study, we constructed a high-precision measuring device of atmospheric carbon dioxide stable isotope ratios, using
wavelength modulation absorption spectroscopy with a newly developed 2.8 µm DFB laser and a Heriot type multi-pass reflection cell. In the measurement, absorption lines are selected in terms of being continuous of 12 CO2 , 13 CO2 and 12 C18 O16 O andsmall interference from water around 2.8 µm. Wavelength modulation absorption spectroscopy allows improved sensitivity andzero background measurement by modulating wavelengths at a high frequency and performing heterodyne detection.
Keywords: carbon dioxide, stable isotope, near-infrared absorption spectroscopy

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AAS21-P08

Room:Convention Hall

Time:May 27 18:15-19:30

Seasonal variation of Pb stable isotope ratio in PM observed in Yakushima Is.
NAGAFUCHI, Osamu1∗ ; YOKOTA, Kuriko2 ; NAKAZAWA, Koyomi1 ; TETSUKA, Kenshi3 ; TETSUKA, Tatsuko3
1

University of Shiga prefecture, 2 Toyohashi University of Technology, 3 Society of Yakushima

A total of 36 sets of PM10 and PM2.5 aerosol particles collected from Yakushima Island during a period from January toJune 2013 were determined for atmospheric Pb concentrations. Among these samples, 36 sets of samples representing two
seasons, winter and spring, were selected for measuring Pb isotopic compositions to determine the relative contributions ofvarious pollution sources. Results reveal an evident seasonality of high spring and comparatively low winter Pb concentrations,
resembling those observed in Beijing, China as well as many East Asian countries. Together with synoptic atmospheric conditions
analysis, the seasonal pattern is attributable to the impact of long-range transport of Pb-rich anthropogenic aerosols from the
Chinese pollution outflows in the northeast monsoon. Results of206Pb/207Pb and 208Pb/207Pb isotope ratios show a minimumat February, thereafter increasing progressively to March and reaching a maximum at April. From January to June, Pb isotope
ratios are quite comparable with those measured in China, especially Dalian and Tianjin. Again this demonstrates YakushimaIsland has already been affected by continental pollution of long-range transport during the northeast monsoon season beginningin winter and ending in late spring.

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AAS21-P09

Room:Convention Hall

Time:May 27 18:15-19:30

Comprehensive analyses of air pollutants at Suzu, Noto peninsula, JapanSADANAGA, Yasuhiro1∗ ; NAKAO, Yuki1 ; ISHIYAMA, Ayana1 ; TAKAJI, Ryo1 ; MATSUKI, Atsushi2 ;IWAMOTO, Yoko3 ; WATANABE, Koichi4 ; SATO, Keiichi5 ; OSADA, Kazuo6 ; BANDOW, Hiroshi1
1Osaka Prefecture University, 2 Kanazawa University, 3 Tokyo University of Science, 4 Toyama Prefectural University, 5 Asia
Center for Air Pollution Research, 6 Nagoya University

Recent remarkable economic progress in East Asia has increased emissions of air pollutants such as nitrogen oxides, sulfur
dioxide, ammonia and volatile organic compounds. Such pollutants are transported over a long distance with photochemical
reactions and then arrive at Japan as aged species such as gas phase nitric acid (HNO3 ), particulate nitrate (NO3 − ), sulfate(SO4 ), peroxy nitrates (PNs), organic nitrates (ONs), ammonium (NH4 + ), organic aerosol (Org) and so on. Many researcheson the transboundary pollution in Japan focus on the areas of western Japan near the Asian continent. On the other hand, it isimportant to investigate the transboundary air pollution in the central Japan area because there are many large cities. In addition,
the central Japan is moderately far from the Asian continent, so that more aged air mass from the Asian continent would comeat the central Japan. In this research, continuous observations of such air pollutants at Suzu, Noto peninsula, Japan. Suzu isrepresentative remote area and located at the central Japan.
Observations are performed at NOTOGRO (NOTO Ground-based Research Observatory) supersite (37.45o N, 137.36o E) in
Suzu. Total odd nitrogen species (NOy ) and total nitrate (T.NO3 = HNO3 + NO3 − ) were measured by a scrubber difference/ NO-O3 chemiluminescence method. PNs and ONs were measured by a thermal dissociation / cavity attenuated phase shift
spectroscopy method. CO, O3 and SO2 were observed by non-dispersive IR, UV absorption, and pulsed UV fluorescencemethods, respectively. Org, NH4 + , SO4 and fine NO3 − were measured by an aerosol mass spectrometer. SO4 was also measured
by a thermal reduction / pulsed UV fluorescence method.
Results of SO4 and T.NO3 were reported in this abstract. The air mass origins were classified into five groups; China andKorea (CK) North China (NC), Japan (JP), Russia (RU), and Sea (S), by backward trajectory analyses. Concentrations of air
pollutants from CK air mass origin were generally high. In many cases, SO4 concentrations from JP were lower than those from
CK, while T.NO3 concentrations from JP were similar to those from CK. In addition, SO4 concentrations from CK were very
high, but T.NO3 concentrations from CK were not, in August 2013 and June 2014. Many of SO4 in remote area is present as
fine particles while NO3 − exists as coarse particles mainly. The deposition velocity of coarse particles (ca. 0.03-1.24 cm s−1 ) islarger than that of fine aerosols (ca. 0.05-0.6 cm s−1 ). In addition, the deposition velocity of HNO3 (ca. 1-8 cm s−1 ) is larger
than that of NO3 − . The lifetime of SO4 is longer than that of T.NO3 , so that SO4 contributes strongly to the transboundary
air pollution at Suzu, in comparison with T.NO3 . In this presentation, more detailed results and discussion, including other air
pollutants will be described.
Keywords: Long-range transport, Air pollutants, East Asia

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AAS21-P10

Room:Convention Hall

Time:May 27 18:15-19:30

Long-term observation of CCN characteristics at Suzu, Noto peninsula, Japan
MATSUKI, Atsushi1∗ ; IWAMOTO, Yoko2 ; KINOUCHI, Kento1
1

Kanazawa University, 2 Tokyo University of Science

Atmospheric aerosols can play a significant role in regulating radiative properties and lifetimes of clouds by acting as cloud
condensation nuclei (CCN). The atmospheric concentrations of CCN are perturbed by major anthropogenic emission sources.
This is particularly true in East Asia and its downwind regions which can be considered by far as one of the global hotspots ofanthropogenic aerosols. Despite the regional relevance, there are still few reports on the variations of CCN properties in relation
to the distinct monsoon and seasonal climate in the region.
In this study, we performed long-term monitoring of CCN activity at the remote coastal site along the Sea of Japan, namely at
the tip of Noto peninsula. Such a remote geographical setting is considered ideal for characterizing CCN over extended periods
with particular emphasis on the effects of typical seasonal atmospheric transport patterns and occasional outflow of atmosphericpollutants.
The measurement was conducted at the NOTOGRO (acronym for NOTO Ground-based Research Observatory) station in Suzu
city (37.45 oN, 137.36 oE) at the tip of a peninsula. The PM10 inlet (14.7 m a.g.l.) provided sample air into the building for theaerosol in-situ measurements. The ambient aerosol was dried by silica-gel before entering into a differential mobility analyzer(DMA, Model 3081, TSI) for size selection. The mono-dispersed aerosol was then guided to a condensation particle counter(CPC, Model 3785, TSI) and a continuous flow thermal gradient CCN counter (CCNC, CCN-100, DMT). The CCNC was operated at four different supersaturation conditions (SS =0.1%, 0.2%, 0.5%, 0.8%). We employed SMCA (Scanning mobility CCN
analysis) method for obtaining the activation diameter dact for each SS (Moore et al., Aerosol Sci. Tech., 2010) from which
the hygroscopicity parameter κ can be derived (Peters and Kreidenweis, Atmos. Chem. Phys., 2007). The bulk chemical composition of non-refractory submicorometer-sized aerosols was also measured simultaneously by an aerosol chemical speciation
monitor (ACSM, Aerodyne Inc.).
The spring and autumn months were characterized by large variation in mass and composition of CCN relevant particles. Thiswas caused by the subsequent arrival of extra-tropical cyclone and anti-cyclone often accompanying transport of polluted continental air-mass. However, unexpectedly high concentrations of fine particles persisted even in summer period, characterized
by relatively large contribution of organics. There was a rather good correlation between the abundance of organics (relative tosulfate) in the aerosol bulk chemical composition and the hygroscopicity κ, such that κ values were particularly low during thesummer period.
There was a further evidence that the temporal variation in κ value was not in phase with org/inorg mass ratios alone, butalso weakly correlated with the organic composition. Analysis of mass spectra from ACSM revealed that the oxidative state oforganics also influenced the κorg . These findings highlight the importance of the temporal variations in particle chemistry as
well as their aging states for conducting CCN closure in the region.

Keywords: aerosol, CCN, Organics, Long-range transport

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AAS21-P11

Room:Convention Hall

Time:May 27 18:15-19:30

Enhancement of dimethylsulfide production by anoxic stress in natural seawater
OMORI, Yuko1∗ ; TANIMOTO, Hiroshi1 ; INOMATA, Satoshi1 ; WADA, Shigeki2 ; THUME, Kathleen3 ;GEORG, Pohnert3
1

National Institute for Environmental Studies, 2 University of Tsukuba, 3 Friedrich Schiller University Jena

Dimethylsulfide (DMS) is the dominant reduced sulfur species in the ocean and an important source of aerosols particles andclouds in the marine atmosphere. Marine DMS plays a key role in the climate system of the Earth. A better knowledge of the
distribution of marine DMS and its controlling factors is required. Previous field studies have reported the formation of DMS
peak upper anoxic layer though the governing processes have not been clearly understood yet. Here we show the first direct
evidence for the enhancement of DMS production caused by anoxic stress.
Isotope tracer experiments were made using the oxic and anoxic coastal seawater to quantitatively evaluate DMS production
rates in three processes; cleavage of dimethylsulfoniopropionate (DMSP), dimethylsulfoxide reduction and phytoplankton release.
Under the anoxic condition, DMS production was considerably enhanced and DMS consumption was inhibited, resulting in an
8-fold higher rate of gross DMS production than that under the oxic condition. While almost all DMS was derived from DMSP
cleavage (99%) under the oxic condition, the DMS production under the anoxic condition was mainly due to direct release of
DMS from phytoplankton (63%). These results demonstrate that phytoplankton suffered from anoxic stress emits DMS into
the seawater, resulting in a rise in DMS levels. Anoxic stress is indicated to be one of important environmental factors in the
dynamics of marine DMS, suggesting the possible global importance due to a ubiquity of anoxic conditions in the coastal oceans.
Keywords: dimethylsulfide, dimethylsulfoniopropionate, dissolved oxygen

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AAS21-P12

Room:Convention Hall

Time:May 27 18:15-19:30

Atmospheric hydorogen mesurements in the western North Pacific
TSUBOI, Kazuhiro1∗ ; MATSUEDA, Hidekazu1 ; SAWA, Yousuke1 ; NIWA, Yosuke1 ; TAKATSUJI, Shinya2 ;FUJIWARA, Hiroaki2 ; DEHARA, Kohshiro2 ; OKUDA, Tomoki2 ; MORI, Yoki2
1

Meteorological Research Institute, 2 Japan Meteorological Agency

Molecular hydrogen (H2 ) plays a significant role in global atmospheric chemistry due to its role in CH4 -CO-OH cycling andwater vapor source in the stratosphere. The balance of H2 could change with the implementation of a new H2 energy carrier.
Therefore, it is important to establish its global budget and atmospheric trend (WMO/GAW Report No.197, 2011).
We started atmospheric H2 measurement at Minamitorishima (MNM) from Nov. 2011. The measurement system using a GCRGD (gas chromatographs equipped with a reduction gas detector) was installed for sirmulteneouse analyses of H2 and carbon
monoxide at 3 stations of MNM, Yonagunijima (YON), and Ryori (RYO) operated by Japan Meteorological Agency (JMA). In
this study, high-precision H2 standard gases are prepared to determine the atmospheric concentrations from the output signal of
the GC/RGD.
The H2 concentrations at MNM varied seasonally from 490 ppb to 560 ppb with a yearly mean of about 520 ppb. The H2variations often show distinct episodic events with enhanced concentrations on a synoptic scale in winter. This result indicatesthat H2 increases are caused by the long-range transport of Asian polluted air masses to the station, suggesting that H2 is a good
tracer for identifying continental air masses in winter season. On the other hand, the H2 concentrations are higher and stable insummer season. This result indicates that the maritime air masses are dominated, and the influence of soil absorption was small.

Keywords: hydorogen

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AAS21-P13

Room:Convention Hall

Time:May 27 18:15-19:30

Observation of optical and chemical properties of aerosols at a forest site in Kii Peninsula
during summer of 2014
KUBODERA, Ryo1∗ ; NAKAYAMA, Tomoki2 ; KAGAMI, Sara3 ; DENG, Yange3 ; OGAWA, Shuhei3 ;MOCHIDA, Michihiro3 ; ADACHI, Kouji4 ; AOKI, Kazuma5 ; MATSUMI, Yutaka2
1

Graduate School of Science, Nagoya University, 2 Solar-Terrestrial Environment Laboratory, Nagoya University, 3 Graduate
School of Environmental Studies, Nagoya University, 4 Meteorological Research Institute, Japan Meteorological Agency, 5 Facultyof Science, University of Toyama

Aerosols scatter and absorb solar radiation and influence to the radiation balance in the atmosphere. Forests are a significant
source of both primary biological aerosol particles (PBAPs) and biogenic secondary organic aerosols (BSOAs). In addition,
polluted air masses including sulfate and black carbon (BC) particles may also be long range transported to forest areas in Japan.
If the BC particles were coated with inorganic and/or organic materials during the long-range transport, the light absorption of
BC could be enhanced due to the lensing effect. However, relations of aerosol optical properties including lensing effect withchemical properties of aerosols in Asian forest area have not been well understood. In this work, optical and chemical properties
of aerosols were simultaneously measured in a forest site in Japan.
The observations were conducted from 17 July to 3 September 2014 at the Wakayama Forest Research Station, Kyoto University, Japan (34.06N, 135.52E, around 535 m above sea level), which is located in the central part of Kii Peninsula. Ambientparticles were sampled from an inlet placed at 6.4 m above ground level. Absorption and scattering coefficients of PM1 particles
were measured using two photoacoustic spectrometers (PASS-3 at λ = 405, 532, 781 nm and PAX at λ = 375 nm, DMT) after
passing aerosols through a heater controlled at 300 ℃ or a bypass line by switching ball valves every 10 min. By comparing
absorption coefficients at 781 nm with and without heating, increase in BC light absorption due to coating can be estimated.
Mass concentrations of non-refractory materials were measured using an aerosol mass spectrometer (AMS, Aerodyne Research).
Mass concentrations of elemental carbon (EC) and organic carbon (OC) were also measured by thermo-optical technique using asemi-continuous EC/OC analyzer (Sunset Lab.). Size distributions of particles were measured using a scanning mobility particle
sizer (SMPS, TSI) and optical particle counters (OPCs, RION and TSI). Aerosol particles were also collected using an impactor
for morphological analysis using a transmission electron microscope (TEM). Optical thickness (AOT) and extinction Angstrom
exponent of aerosols were also measured using a Skyradiometer (Prede). In the presentation, relation between the obtained optical properties with chemical and physical properties of aerosols will be discussed.

Keywords: Aerosol optical property, Ambient measurement, Forest site, Biogenic SOA, Lensing effect, Photoacoustic spectroscopy

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AAS21-P14

Room:Convention Hall

Time:May 27 18:15-19:30

Chemistry with KROME: Dynamical photochemical solver coupled to chemical disequilibrium and sulfur isotopes
DANIELACHE, Sebastian1∗
1

Sophia University Faculty of Science adn Technology Department of Materials and Life Science

The study of chemical networks of Earth’s geological past such as the Archean and Exoplanetary atmospheres requires theresolutions larges number of chemical reactions. This necessity is based on the lack of observational parameters abundant in today’s planet Earth or neighbor planets in the solar system. The aim of this work is to construct a planetary atmosphere chemical
network solver that relies on a minimal number of observational parameters.
We present here the latest development in our effort to develop such model. Our previous report presented the efficiency of thechemical solver for a large number of chemical species and reaction networks. In this report we present a photochemical dynamic
core capable of solving ultraviolet opacities and photo-dissociation reaction rates at each step of the calculation. Additionallythe model has been equipped with a set of equations to calculate disequilibrium effects on the chemical network. The stability
and robustness of the code has been tested for a large network with more than 500 reactions interlinking more than 40 chemical
species. The results obtained so far have been contrasted with the most common chemical codes available in the literature forbenchmark.

Keywords: Archean Atmosphere, Sulfur Isotopes

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AAS21-P15

Room:Convention Hall

Time:May 27 18:15-19:30

Urban fog and atmospheric pollution: contrasted effects on pollutants in Lyon (France)
RENARD, Florent1∗ ; FUJIKI, Kenji1
1

University Jean Moulin Lyon 3, UMR 5600

Lyon (500 000 inhabitants), located in the southeastern France, is an industrial city, with a polluted atmosphere and many daysof fog. This unfavorable atmospheric situation poses many health problems to people and harms the attractiveness of the cityand the development of trade. Greater Lyon has the highest levels of fine particulates and nitrogen dioxide in the Rhone-Alpes
region and is prosecuted by the European Union for non-compliance with the Directive of 21 May 2008 concerning the qualityof ambient air and cleaner air for Europe. This area is disadvantaged by its geographical situation, with the presence of two
major rivers (Rhone and Saone) and many reliefs, influencing the conditions of dispersion of pollutants in the atmosphere andmakes the Lyon an atmospherically sensitive city, despite prevailing winds North-South or South-North oriented which tend tofavor the dispersion of pollutants In addition, Lyon concentrates pollution from traffic, industrial, and tertiary sectors. In winter,temperature inversions (temperature higher in altitude than on the ground) promote stagnation of pollutants at low altitude. Thisphenomenon is amplified considerably during episodes of urban mist. As a first step, the evolution of the number of foggy daysis studied, and explanatory factors are proposed. The months of October to January are the most affected, with an average of
7 days of fog in December and January, over the period 1949-2013. It is thus noticed a steady decline in the number of foggy
days since 1921 until early 2000s, from more than 90 days to only fifteen, followed by stagnation and a slight increase in recent
years. This trend is compared to the annual minimum temperatures of Lyon, following an opposite trend, with an increase until
the late 2000s, from 6 degrees C to 9 degrees C, followed by a stagnation and a slight decrease. A strong relationship is obtained
between these two parameters, but the average wind speed may also explain the decrease, limiting conditions for fog formation,with a more important mixing of the air. Again, it can be noticed an increase in the average wind speed and in the proportion ofwinds faster than 1 m / s until the early 2000s, and then a decrease. Finally, better controls of industrial air emissions also explain
the decrease in the number of days with fog over the long term. In a second step, the concentrations of air pollutants (PM10,
PM2.5, 03, NO2, NO and SO2) are studied with and without fog. A station in the center of the city records these pollutants since2007 continuously, every hour. In 2013, during foggy days and comparatively to clear days, it is found a strong increase in PM
10 and PM 2.5, respectively from 22.3 µg.m-3 and 16.8 µg.m-3 to 39.7 µg.m-3 and 33 µg.m-3, above recommended thresholds.
Concentrations of nitric oxide (NO) and nitrogen dioxide (NO2) are respectively 9.0 µg.m-3 and 27.7 µg.m-3 during clear days,
passing to 52 8 µg.m-3 and 50.5 µg.m-3 during foggy days, exceeding the recommended values here too. And inversely, as aresult of sunlight blocking by water droplets in suspension, there is a decrease in O3, from 42.4 µg.m-3 to 13.9 µg.m-3, while
the SO remains stable and very low, at 1.2 µg.m-3(fig. 1). These observations made in 2013 are the same since 2007. Finally, theevolution of the concentration of PM 10 is studied during persisting foggy days, hours after hours. There is a steady and dramaticincrease in the concentration with consecutive days of fog, going to an increase of 40 µg.m-3 on the fourth day. In conclusion, air
pollution in urban areas under clear skies is already a major concern, but the action of the latter on health is particularly worrying
during episodes of urban smog.
Keywords: fog, atmospheric pollution, particulate matter, Lyon, France

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AAS21-P16

Room:Convention Hall

Time:May 27 18:15-19:30

Impacts of weather regimes on PM10 pollution peaks in Rhone-Alpes (France)
RENARD, Florent1∗ ; FUJIKI, Kenji1
1

University Jean Moulin Lyon 3, UMR 5600

Pollution in particulate matter is a more and more significant problem, especially in urban areas, and widely publicized whenregulatory thresholds are exceeded. Health consequences have to be carefully considered, for both short-term and long-term
effects. First, this paper describes the spatial and temporal distribution of PM10 concentrations (particulate matter with a diameter inferior to 10 µm) in urban environments in the Rhone-Alpes administrative area, located in South-east France. Pollution
monitoring stations are grouped together by ascending hierarchical classification. The goal is to identify similar patterns on aregional scale. Then, this PM10 distribution is analyzed according to synoptic-scale weather regimes. As the classic analysis
between anticyclonic and cyclonic types appears insufficient, particulate matter concentrations are related to weather regimes
according to Hess-Brezowsky classification system, which is widely used in Western Europe for numerous climate studies. The
latter has been chosen after a review of the existing European classifications, and this analysis is one of the first to be made inFrance. Results show that strong annual disparities are observed amongst the different urban monitoring stations in Rhone-Alpeson both spatial and temporal scales. More precisely, stations in deep alpine valleys and in the regional capital city Lyon are themost polluted ones. Concerning monthly means, the most polluted months are obviously those in winter, due to the emitting
sources considered. Steepest gaps are nonetheless better observed on an hourly basis, with two peaks at the end of the morningand at early evening. When analyzed according to the weather regimes, high pressure area over Central Europe weather regimes
are prevailing during information and alert thresholds exceedances. More specifically, six regime types (Groswetterlagen) arestrongly associated with pollution peaks. Two are cyclonic (WZ and NWZ) and their persistence during several consecutive
days leads to a decrease in pollution. They are only associated with pollution peaks because they have represented a large partof global circulation during the last few years. By contrast, the most worrying regime types in regard with pollution peaks are
anticyclonic : SWA, WA, HM, and BM. Those last two types, when persisting over several days, lead to a steep increase inpollutant concentrations.
Keywords: particulate matter, pollution peaks, weather regimes, Hess-Brezowsky, Lyon, France

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AAS21-P17

Room:Convention Hall

Time:May 27 18:15-19:30

Height-resolved measurements of the aerosol size distributions in a temperate forest by
tower observation system
TAKAHASHI, Kenshi1∗ ; YABUKI, Masanori1 ; MATSUDA, Kazuhide2 ; TSUDA, Toshitaka1
1

RISH, Kyoto University, 2 Faculty of Agriculture Field Science Center, Tokyo University of Agriculture and Technology

Dry and wet depositions are quite important for aerosol particles to be removed from the atmosphere. Also deposition ofammonium, sulfate, and nitrate contained in aerosol particles may contribute to potential acidification and eutrophication of theecosystems. Both deposition processes are size specific, in particular, dry deposition of aerosol particles depends principally on
particle size, atmospheric turbulence and stability and the collecting properties of the surface.
We conducted observational studies measuring the number size distributions of ambient submicron and ultrafine aerosol particles in a deciduous forest, during the summers of 2013 and 2014. The deciduous forest is located in suburban Tokyo, as a partof the experimental forest at the Tokyo University of Agriculture and Technology (Field Museum Tamakyuryo (FM Tama)). The
observation site has a 30-m tall tower where we installed aerosol measurement instruments of the Scanning Mobility Particle
Sizer and the Optical Particle Counter to explore the vertical profiles of the aerosol size distributions within and above the forest
canopy. We report that the size distribution for submicron particles varied significantly with both temporally and vertically, depending on the wind field as well as the relative humidity related to the hygroscopic properties of aerosol particles.

Keywords: atmospheric aerosol, size distributions, tower observation

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AAS21-P18

Room:Convention Hall

Time:May 27 18:15-19:30

Direct measurements of photochemical ozone production rate at a forest area in Japan
during summer of 2014
KAWASAKI, Shio1∗ ; SADANAGA, Yasuhiro1 ; TSURUMARU, Hiroshi2 ; IDA, Akira2 ; KISHIMOTO, Iori2 ;KAJII, Yoshizumi2 ; NAKAYAMA, Tomoki3 ; BANDOW, Hiroshi1
1Osaka Prefecture University, 2 Kyoto University, 3 Nagoya University

We developed a direct measurement system of photochemical ozone production rate in order to evaluate ozone concentration
variations quantitatively. In fact, this system measures oxidant (Ox = O3 + NO2 ) production rate. The use of Ox can ignore theconcentration variations of O3 due to titration of O3 by NO. The field campaign was performed at Wakayama, a remote site,in Japan during summer of 2014. Measurement parameters were photochemical net Ox production rate (P-L (Ox)), [O3 ], [NO],[NO2 ], [RO2 ], [VOCs], OH reactivity, photolysis frequencies of various trace species and so on.
The P-L (Ox) measurement system has “reaction” and “reference” chambers. The reaction and reference chambers (17.1-cm
inner diameter and 50-cm length) are made of quartz and Pyrex, respectively. Inner walls of both the chambers are coated withclear Teflon films to avoid wall loss of O3 . An outer wall of the reference chamber is coated with a UV-cut film (50% cutoff
wave length of 405 nm). Both the chambers were put in an outdoor location to be exposed directly to sunlight. Ambient air is
introduced into both the chambers. In the reaction chamber, photochemical reactions proceed to generate Ox. On the other hand,Ox is not generated in the reference chamber. The difference of Ox concentrations (∆Ox) in air from the two chambers is the Ox
produced by photochemical reactions in the reaction chamber. The P-L (Ox) is obtained by dividing ∆Ox by a mean residence
time of air in the reaction chamber. Ox concentrations were obtained as follows. O3 in Ox is converted into NO2 by the reactionof O3 with large excess of NO, and then the NO2 concentration is measured by a laser-induced fluorescence technique.
The field campaign was conducted at Field Science Education and Research Center, Kyoto University, Wakayama Forest
Research Station, in Wakayama Prefecture, Japan. Observation site is in forest area and anthropogenic sources of air pollutants
are very low. Observations were conducted from 28 July to 8 August. Most periods of the campaign, O3 concentrations wereapproximately 10 ppbv in the daytime. NOx (= NO + NO2 ) concentrations were less than about 1 ppbv throughout the campaign.
BVOCs (Biogenic Volatile Organic Compounds) concentrations were high. Results of P-L (Ox) and Ox concentration on 6
August were reported in this abstract. A diurnal variations were observed for P-L (Ox) and Ox concentration, and the maximum
rate and concentration were observed around noon. Ox concentration increased in the early morning, while P-L (Ox) was still
0 ppbv h−1 and then increased after a few hours. This result shows that O3 concentration is increased by non-photochemicalfactors in the early morning. Vertical mixing of air is week at night and O3 concentration near the surface of the ground decreases
by deposition, reactions with olefin and so on. Surface of the ground is gradually warmed by sunlight in the morning and verticalmixing of air is activated. O3 concentration would increase because of O3 influx from above. P-L (Ox) achieved a peak value
around noon and photochemical O3 production was active in the daytime. Ox concentration did not increase around noon,
however. This suggests that O3 increase by photochemical production competes against O3 decrease by non-photochemicalfactors such as deposition, advection, and reactions of O3 with olefin.
Keywords: photochemical ozone production rate, oxidant, forest area

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AAS21-P19

Room:Convention Hall

Time:May 27 18:15-19:30

A global trend map of seasonal total column ozone using a MIROC3.2 nudged ChemistryClimate Model
OBAMA, Risa1∗ ; AKIYOSHI, Hideharu1 ; KADOWAKI, Masanao1 ; YAMASHITA, Yousuke1
1

National Institute for Environmental Studies, 2 Atmospheric and Ocean Research Institute, The University of Tokyo, 3 Japan
Atomic Energy Agency
We created a global trend map of seasonal total column ozone using the results of two CCM experiments to examine theinfluence of CFC on global total column ozone. The model used is the MIROC3.2 Chemistry-Climate Model nudged toward
ERA-Interim reanalysis data. We performed two experiments. One experiment (REF-C1SD) uses observed ozone depleting
substance (ODS) and greenhouse gas (GHG) concentrations that changes with time. In the other experiment (SEN-fODS1979),
ODS concentration is fixed to the 1979 value. The REF-C1SD experiment shows a large decreasing seasonal total column trend
globally during the CFC decreasing period (1979-1996). The trends have clear longitudinal structures at winter mid-latitudes andspring polar region.
Comparing the result of the REF-C1SD experiment with that of the SEN-fODS1979 experiment, the contributions of ODS andother processes except for ODS (for example, trends in ozone transport) are analyzed globally. We also show the trend map for
the ODS decreasing period (1997-2011).
Keywords: Total Column Ozone, Trend, Chemistry-Climate Model, Global Map, ERA-Interim

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AAS21-P20

Room:Convention Hall

Time:May 27 18:15-19:30

Trend analysis of satellite observed tropospheric NO2 vertical column density over EastAsia
MUTO, Takuya1∗ ; IRIE, Hitoshi2 ; ITAHASHI, Syuichi3
1

Graduate School of Advanced Integration Science, Chiba University, 2 Center for Environmental Remote Sensing, Chiba University, 3 Central Research Institute of Electric Power Industry

Nitrogen dioxide plays a central role in the atmospheric environment as a toxic substance for respiratory system and precursorsof ozone and aerosols. Furthermore, OH concentration is dependent on nitrogen dioxide concentration in the atmosphere. Although Hilboll et al.(2013) showed an increase in NO2 concentration over Central Eastern China(CEC) until 2011 and a gradualdecrease in NO2 concentration over Japan until 2011, the latest trend until 2014 has not been reported yet. The time period isof interest, because it corresponds to the 12th 5-year-plan regulating NOx emissions in China and the period with the power
substitution of thermal power generation for the nuclear power generation in Japan. In this study, we used two satellite datasetsfrom OMI and GOME-2 that have been operationally observing tropospheric NO2 VCD in recent years until 2014. Tropospheric
NO2 VCD trends in China and Japan were estimated based on the regression analysis for annual mean values. Although anincrease in NO2 VCD occurred at a rate of 7% per year from 2005 to 2011 over Central Eastern China, we found a decrease at a
rate of 11% per year from 2011 to 2014. Over Japan, the NO2 VCD increased at a rate of 4% per year from 2005 to 2011 anddecreased from 2011 to 2014 at a rate of 4% per year. In this presentation, we also conduct detail trend analysis on a grid basis
to discuss the potential causes for these variations in NO2 VCD over China and Japan.
Keywords: Nitrogen dioxide, OMI, GOME-2, trend analysis

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AAS21-P21

Room:Convention Hall

Time:May 27 18:15-19:30

CH4, H2O, N2O, and temperature from the mid-troposphere to the stratosphere in thenorthern mid- and high-latitudes
SUGITA, Takafumi1∗ ; SAITOH, Naoko2 ; HAYASHIDA, Sachiko3 ; MACHIDA, Toshinobu1
1

NIES, 2 Chiba Univ., 3 Nara Women’s Univ.

Profiles of CH4 have been retrieved from satellite-borne nadir sensors since 1996 by measuring thermal infrared (TIR) emissions from the Earth’s atmosphere. GOSAT/TANSO-FTS has been operated since 2009. Profiles of CO2 and CH4 are retrieved
from the TIR band of the TANSO-FTS. In this study, we assess data quality for CH4 , H2 O, N2 O, and temperature between the
mid-troposphere and the stratosphere, contributing the improvement of our knowledge on CH4 distributions, for instance, in thewestern Siberia. For comparisons with the TIR data, we used the solar occultation sensor, ACE-FTS, and the routine aircraft
observations in the western Siberia. We found that (1) TIR CH4 mixing ratios are systematically larger than ACE-FTS CH4 in
the 400-200 hPa levels between January and April in 2010/2011, especially in January, several profiles exceeded 2.0 ppmv of
CH4 at the 300 hPa level. (2) TIR H2 O mixing ratios are larger than ACE-FTS H2 O in the 300-250 hPa levels and the above
throughout the period studied. (3) TIR CH4 at the 7 km (430 hPa) and the 5.5 km (500 hPa) altitudes are in good agreement withthose from the aircraft observations from the temporal variation view within the range of variations in TIR CH4 .
Acknowledgements: We thank Kaley A. Walker, University of Toronto, Canada for providing us the Version 3.5 ACE-FTS
data through http://ace.uwaterloo.ca. This research was supported by the Environment Research and Technology Development
Fund (ERTDF) of the Ministry of the Environment, Japan (A1202). Aircraft observations in the western Siberia are conducted
by NIES with the cooperation of Russian Academy of Science (RAS).
Keywords: methane, troposphere, stratosphere, GOSAT, aircraft

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AAS21-P22

Room:Convention Hall

Time:May 27 18:15-19:30

Comparisons between NICAM-TM and GOSAT/TANSO-FTS TIR CO2 data
SUGIMURA, Ryo1∗ ; SAITOH, Naoko1 ; IMASU, Ryoichi2 ; KAWAKAMI, Shuji3 ; SHIOMI, Kei3 ; NIWA, Yosuke4 ;MACHIDA, Toshinobu5 ; SAWA, Yousuke4 ; MATSUEDA, Hidekazu4
1

Center for Environmental Remote Sensing, Chiba University, 2 Atmosphere and Ocean Research Institute, The University ofTokyo, 3 Japan Aerospace Exploration Agency, 4 Meteorological Research Institute, 5 National Institute for Environmental Studies
Greenhouse gases Observing SATellite (GOSAT), which was the first satellite for global observations of greenhouse gases, wassuccessfully launched on 23 January 2009. Our recent analysis suggested that CO2 vertical profiles retrieved from Thermal andNear Infrared Sensor for Carbon Observation (TANSO) - Fourier Transform Spectrometer (FTS) thermal infrared (TIR) band had
a negative bias in the middle troposphere. In this study, we globally evaluated the magnitude of the bias through the comparisons
between the TIR CO2 data and Nonhydrostatic Icosahedral Atmospheric Model - based Transport Model (NICAM-TM) CO2
data [Niwa et al., 2011]. Furthermore, we calculated a correction factor to modify the bias for each latitude band and applied thelatitude-dependent correction factors to the TIR CO2 data on 500 hPa; here, we estimated the correction factors on the basis ofcomparisons between CO2 profiles observed over airports by Continuous CO2 Measuring Equipment (CME) in Comprehensive
Observation Network for Trace gases by Airliner (CONTRAIL) project [Machida et al., 2008] and the coincident TIR CO2
profiles. Then, we analyzed seasonal variations of the modified TIR CO2 data to check the validity of the correction factors
estimated here.
Comparisons of the differences of CO2 concentrations on 500 hPa and 200 hPa (500 hPa minus 200 hPa) between TIR CO2
data and NICAM-TM CO2 data showed that the differences of the TIR CO2 data were larger than those of the NICAM-TM CO2
data because of the negative bias of the mid-tropospheric TIR data. The CO2 differences between the two pressure levels of the
TIR data were particularly large (˜8 ppmv) in low latitudes; this characteristic was not seen both in the NICAM-TM CO2 data
and the a priori CO2 data (NIES-TM05). Next, we applied the latitude-dependent correction factors to the TIR CO2 data on 500
hPa, and then compared the CO2 differences on 500 hPa and 200 hPa. In low latitudes (25 ⁰ S-25 ⁰ N), the CO2 differences
between the two pressure levels of the TIR data became closer to the CO2 differences of the NICAM-TM CO2 data and the apriori CO2 data when we applied the correction factor estimated over Bangkok. On the other hand, in northern high latitudes(northern latitudes of ˜40 ⁰ N), most of the CO2 differences between the two pressure levels of the TIR data were positive
unlike the NICAM-TM CO2 and the a priori CO2 data when we applied the correction factor estimated over Amsterdam. In
boreal summer, surface CO2 concentrations are lower than middle and upper tropospheric CO2 concentrations; in that sense, thecorrection factor applied here was not appropriate in northern high latitudes in summer. These results suggest that the magnitudeof the negative bias seen in TIR CO2 data would vary depending on seasons as well as regions, and therefore, we should estimate
a latitude-dependent correction factor for each season.
Furthermore, we compared time series of TIR CO2 data with those of NICAM-TM CO2 data and the a priori CO2 data
for several different regions that were categorized in terms of climatic divisions and latitude bands [Niwa et al., 2011]. Our
preliminary results showed that the seasonal variations of the TIR CO2 data in some regions were closer to those of the NICAM
CO2 data than of the a priori CO2 data. For future work, we should review how to compare the three CO2 data sets, and thenclosely analyze the differences in seasonal variations among the three data sets globally.
Acknowledgements
We thank the staff and engineers of Japan Airlines, the JAL Foundation, and JAMCO Tokyo for supporting the CONTRAIL
project.

Keywords: CO2, satellite remote sensing, GOSAT

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AAS21-P23

Room:Convention Hall

Time:May 27 18:15-19:30

Validation of GOSAT/TANSO-FTS TIR CO2 profiles using aircraft CO2 data
KIMOTO, Shuhei1∗ ; SAITOH, Naoko1 ; IMASU, Ryoichi2 ; KAWAKAMI, Shuji3 ; SHIOMI, Kei3 ;MACHIDA, Toshinobu4 ; SAWA, Yousuke5 ; MATSUEDA, Hidekazu5 ; UMEZAWA, Taku4
1

Center for Environmental Remote Sensing, Chiba University, 2 Atmosphere and Ocean Research Institute, The University ofTokyo, 3 Japan Aerospace Expolation Agency, 4 National Institute for Environmental Studies, 5 Meteorological Research InstituteGreenhouse gases Observing SATellite (GOSAT) was launched on 23 January 2009 to observe major greenhouse gases suchas CO2 and CH4. Thermal and Near-infrared Sensor for Carbon Observation Fourier Transform Spectrometer (TANSO-FTS) on
board the GOSAT can observe CO2 profiles in the thermal infrared (TIR) region, but the quality of the retrieved CO2 profile data
has not yet been fully validated. In this study, we compared GOSAT/TANSO-FTS TIR CO2 profiles with aircraft CO2 data toevaluate their quality. The aircraft data we used were obtained by Comprehensive Observation Network for Trace gases by Airline (CONTRAIL) project and Civil Aircraft for the Regular investigation of the atmosphere Based on an Instrument Container(CARIBIC) project, both of which are commercial airliner projects.
First, we assumed CONTRAIL data obtained during ascending and descending flights over airports as a ”CO2 profile”, andthen compared TIR CO2 profiles with the CONTRAIL CO2 profiles to which the TIR averaging kernel functions were applied.
We adopted a distance between the GOSAT observation and the airport within 300 km and a time difference between the two
observations within 72 hour as criteria for the comparison. Here, we used the CONTRAIL profile data obtained over the ten airports: Moscow, Amsterdam, Vancouver, Narita, Delhi, Honolulu, Bangkok, Singapore, and Djakarta. We also used CONTRAIL
and CARIBIC level flight data to validate the global distributions of TIR upper tropospheric CO2 data. We divided the level
flight aircraft data into several regions, and then compared the averaged aircraft data with the averaged TIR data in each region.
From the CO2 profile comparisons at each airport, we found the TIR data had a low bias of 1-1.5%. The magnitude of thebias varied depending on seasons and latitudes; in spring and summer in low latitude, the magnitude of the bias was larger thanthat in autumn and winter in mid and high latitudes. From the upper tropospheric CO2 comparisons, the TIR data showed better
agreements to the aircraft data than the a priori data, and the distribution of the TIR upper tropospheric CO2 data had a similar
pattern to the distribution of the aircraft data. In the poster, we will also report the details of the comparisons using other aircraftdata.
Acknowledgements
We thank the staff and engineers of Japan Airlines, the JAL Foundation, and JAMCO Tokyo for supporting the CONTRAIL
project. CARIBIC data used in this study were provided by the CARIBIC project. We also thank Dr. C. Brenninkmeijer andother members of the CARIBIC project.
Keywords: GOSAT, validation, CO2, aircraft measurement

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AAS21-P24

Room:Convention Hall

Time:May 27 18:15-19:30

Climatology of spatiotemporal variations of tropospheric CO2 observed by CONTRAILCMEUMEZAWA, Taku1∗ ; MACHIDA, Toshinobu1 ; SAWA, Yousuke2 ; MATSUEDA, Hidekazu2 ; NIWA, Yosuke2
1

National Institute for Environmental Studies, 2 Meteorological Research Insitute

CONTRAIL is the ongoing project that measures atmospheric trace gases during intercontinental flights of Japan Airlines.
Atmospheric CO2 concentration is analyzed using Continuous CO2 Measuring Equipment (CME) onboard the aircraft. From ˜20
thousands of measurement flights since 2005, extensive number of CO2 data (˜2 millions) along level-flight and ascent/descent
tracks have been obtained, enabling us to well characterize spatiotemporal distributions of atmospheric CO2 covering largepart of the globe especially the Asia-Pacific regions. In this study, we define 4CO2 as a deviation from the long-term trend
observed at a northern hemispheric baseline station Mauna Loa, Hawaii, to illustrate climatological CO2 distributions including
seasonal and shorter-term variations. For instance, over airports in Japan, 4CO2 reaches seasonal maximum at the end of April
with higher values near the surface. In this season, high 4CO2 spreads east of the Asian continent in the upper troposphere
over the northern Pacific. In contrast, seasonal minimum of 4CO2 occurs in September with more depletion in the upper
troposphere. The summertime low 4CO2 in the upper troposphere appears to be more pronounced over the Asian continent thanover the Pacific. Likewise, we present seasonal variations of vertical profiles of tropospheric 4CO2 over various airports and of
spatial distributions in the upper troposphere in large-scale perspective, and discuss them from viewpoints of seasonally varying
continental sources/sinks and atmospheric transport.
Keywords: CONTRAIL, CO2, troposphere, seasonal variation, vertical profile

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