Optical remote sensing of atmospheric pollutants
大気汚染物質の光学的リモートセンシング
Center for Environmental Remote Sensing (CEReS), Chiba University
Hiroaki Kuze, Professor, [email protected]
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2016年 RS環境情報学 I
Air pollution大気汚染
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Urban smog: PM2.5
Los Angels Alberta, Canada
Beijing
http://ipod.item-get.com/2013/01/pm25.php 3
PM2.5, PM10 and SPM➣ In USA, a new environmental standard of PM2.5 was added in 1997 to the existing standard of PM10.➣ In Japan, the standard for PM10 was established in 1972. The suspended particulate matter (SPM) was defined as particles with diameters less than 10 m.
http://www.nies.go.jp/kanko/news/20/20-5/20-5-05.html
Col
lect
ion
Effic
ienc
y
Particle Diameter (m) 4
PM2.5 production in the atmosphere
UV photons produce ozone from VOC & NOx
人為起源
自然起源
http://www.env.go.jp/air/osen/pm/info.html
VOC SOxNOx
PM2.5
O3
NMHC
SPM
NMHC (nonmethane hydrocarbons 非メタン炭化水素) VOC (volatile organic compounds 揮発性有機化合物)
VOC
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Asian dust event observed on April 8, 2006
Aqua/MODIS visible band (RGB)
http://fujin.geo.kyushu-u.ac.jp/~hayasaki/
SPM distribution on the same day, (11:00, 14:00, and 23:00) observed at 1500 General (non-roadside) sampling stations.
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http://soramame.taiki.go.jp/
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Andersen Sampler (Multi-stage cascade impactor)
http://www.h2.dion.ne.jp/~yokke/study/atmosphere/air_pm/air_pm.html
Aerosol particles accumulate on a filter paper.
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http://www.t-dylec.net/products/pdf/thermo_5030.pdf
Sampling instrument for SPM & PM2.5【Hybrid monitor SHARP5030 】
○ 分粒装置で分粒された気流は、除湿部を通過して検出部へ入る。 Sampled air is introduced into the detector part through the dehumidify section.
○ 光散乱測定部(ネフェロメータ)では、エア
ロゾルの通過により発生する散乱光の強度から、濃度を測定(光散乱法)。光源の波長は880 nmである。 A nephelometer is used for measuring light scattering signals.
○ ネフェロメータを通過後、エアロゾルはグラ
スファイバーフィルタの上に捕集される。捕集前後のβ 線強度を検出し、その減衰量からエアロゾルの質量を計測する(β 線吸収法)。β 線は、14Cから放射される。A β ray counter is employed for the aerosol mass measurement.
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日本のエネルギー供給量
http://www.j-ec.or.jp/ecinfo/HoukiKankyo/kankyomondai3_1_1-1-2.html
○ 日本の実質経済成長率は、昭和30年代の約9%から昭和40年代前半には約11%に上昇した。Economic growth rate was 11% in mid 1960s.
○ 昭和36年には石油需要が石炭需要を上回り、昭和30年から昭和36年の間にエネルギーの総供給量も約2倍に増加した。 Oil consumption drastically increased during 1955-1960.
○ 昭和40年頃の大気汚染が最も著しかった時期には、場所によっては、硫黄酸化物やばいじん等によって視程が30~50 m にまで落ち込むとともに、硫黄酸化物による刺激臭が立ちこめているところもあった(四日市、川崎、千葉、北九州 ...)。Because of air pollutants, visibility decreased to 30 m in industrial areas.○ こうした深刻な環境汚染は公害と呼ばれた。昭和30年代から40年代にかけ、いわ
ゆる四大公害病(水俣病、新潟水俣病、イタイイタイ病、四日市ぜんそく)の発生など大きな社会問題になった。 Serious illness like mercury pollution, Asthma, etc.
経済成長期の公害 Pollution in Japan
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Mizushima Industrial Complex
Sapporo in 1970s PM2.5 in Beijing
大気汚染の記録写真
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Long-term trend of NO2 and SPM concentration
NO2 concentration
SPM concentration
Roadside
Roadside
General
General
ppm
mg/
m3
Ground sampling measurement at around 2000 stations (roadside: 500)
Environmental standard
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SO2 emission
In Japan:1970-2010 0.035 ppm→ 0.003 ppm(sampling station measurement)
http://www.nies.go.jp/kanko/tokubetu/setsumei/sr-065-2006b.html
kilo-ton SO2in 0.5o×0.5o
mesh(2000)
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1970-2010
Global distribution of PM2.5
(g/m3)
Donkelaar et al., http://ehp.niehs.nih.gov/0901623/
➣The global ground-level PM2.5 concentrations are mapped using total column aerosol optical depth (AOD) from the MODIS and MISR satellite instruments and coincident aerosol vertical profiles from the GEOS-Chem global chemical transport model. Global estimates of long-term average (1 January 2001 to 31 December 2006) PM2.5 concentrations at approximately 10 km × 10 km resolution indicate a global population-weighted geometric mean PM2.5 concentration of 20 µg/m3.
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Q1 大気汚染の原因となる物質にはどのようなものがあるか。Describe important substances that cause air pollution.
Q2 エアロゾルとは何か。日常生活にどのような影響を与えているか。What are aerosol particles? What influences do they have in our daily life?
Mie scattering of aerosol
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http://en.wikipedia.org/wiki/File:Atmospheric_electromagnetic_opacity.svg
Atmospheric Opacity 大気の不透明度
Wavelength
Opa
city
=3 m =100 MHz=30 cm =1 GHz
大気の窓可視 近赤外 電波
Molecular absorption is absent in visible range→ Atm. visibility is controlled by aerosol particles
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大気の鉛直透過における散乱と吸収の光学的厚さVertical optical thickness due to scattring and absorption
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光学的厚さ Optical thickness Vertical radiation transfer when J = 0
IdzdI
constant α
eI
eI
TIIz
0
0
0
Lambert-Beer’s law
0I
eI0 =α z =nz : optical thickness
(=1 I = 0.37I0 )
➣ Clouds appear white, since wavelength dependence of Mie scattering is moderate.➣ White haze is due to the presence of aerosol particles.
ミー散乱 Mie scattering
Gustav Mie 1869-195719
冬季の接地逆転層Inversion layer in winter morning
12:19 on 19 January 2010 at CEReS, Chiba University
Temperature
Alti
tude
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Aerosol particles and gaseous pollutants
エアロゾル粒子 Aerosol particles➣ Aerosol – liquid or solid particles floating in the atmosphere. The diameter varies from 10 nm to 10 m.➣ Cloud droplet – also, liquid or solid (ice) particles, but with larger diameters of 10-100 m.➣ Mie scattering occurs since the size of aerosol and cloud particles are similar to or larger than the optical wavelength. Aerosol Cloud
(satellite image)soot
hygroscopic saltsea salt
Indoor aerosol1m
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0.0
0.5
1.0 Soil Sea Salt Nitrate Sulfate Organics EC
Volu
me r
atio
0.0
0.5
1.0
Volu
me r
atio
1999 2000 2001 2002 2003 20040.0
0.5
1.0Coarse
Volu
me r
atio
Fine
Long-term aerosol analysis at Chiba UniversityFine particles
Coarse particles
S. Fukagawa et al., Atmos.Environ., 40, 2160-2168 (2006) 22
Clean room
http://ja.wikipedia.org/wiki/
➣ Particles larger than 0.5 m, including floating bacteria and fungi, should be removed for medical and food industry.➣ Particles larger than 0.5 – 1 m must be removed in the case of semi-conductor manufacturing.➣ Ambient atmosphere corresponds to 1E+06 under clear sky. The number density drastically decreases under rainy conditions (600,000 – 200,000).
unit: particles/m3
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入射太陽エネルギー(100)
大気と雲による吸収(25)
大気と雲による反射(25)
反射太陽エネルギー(30)
(25)
(29) (12) (4)
大気と雲からの再放射(25)
外向き赤外光エネルギー(70)
地表面による吸収(45) 地表面による
反射(5)
水蒸気の凝結
地表面からの再放射
(104)温暖化気体の効果
(88)
再吸収
潜熱
(24)
対流
(5)
海流による熱の輸送
Principles of Environmental Science
Aerosols and clouds - large impact on the Earth's radiation budget
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http://www.mri-jma.go.jp/Project/1-21/1-21-1/aerosol-en.htm
How aerosols control the atmosphere
放射の直接効果 放射の間接効果
放射の散乱と吸収 雲の凝結核としての作用
湿性沈着
ジメチルサルファイド
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Global map at 18 km resolution showing monthly average AOT at 865 nm over water surfaces for June, 1997, derived from radiancemeasurements by POLDER aboardADEOS satellite.
POLDER (POLarization and Directionality of the Earth‘s Reflectance) ADEOS (ADvanced Earth Observing Satellite)[August 1996]
Global distribution of aerosol optical thickness (AOT)
J. Heintzenberg et al.,, Atmospheric chemistry in a changing world 26
Q1 大気汚染の原因となる物質にはどのようなものがあるか。Describe important substances that cause air pollution.
Q2 エアロゾルとは何か。日常生活にどのような影響を与えているか。What are aerosol particles? What influences do they have in our daily life?
Q3 エアロゾルが地球の放射収支に与える影響を直接効果、間接効果を含めて説明しなさい。Discuss how aerosols impact the Earth's radiation budget, including both direct and indirect effects.
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http://www.horiba.com/scientific/products/particle-characterization/
Mie scattering includes all the optical processes of reflection, refraction, and diffraction, etc.
Forward scattering becomes dominant for larger particles.
http://homework.uoregon.edu/pub/class/atm/scatter.html 28
2
22
21
20
20
2)()(
)(k
FFRI
dd
RII scat
Scattered radiance
Differential cross-section
1
1 coscos112
lllll ba
lllF
Scattering amplitude
cossin
1cos 1ll P
1
2 coscos112
lllll ab
lllF
,
coscos 1ll P
dd
Associated Legendre function
ミー散乱理論 Mie theory
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kakannkakan
kakannkakanallll
lllll
~~ ~ ~~ ~
:complex refractive indexn~
:radius of the spherea
/2k kakankakann
kakankakannbllll
lllll
~ ~~ ~ ~~
sin11 1
lll
l dd
cos11 1
lll
l dd
lln i
Complex refractive index and radius of dielectric sphere
wavenumber
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l-th partial wave
:complex refractive indexn~
a : radius of the sphere
/2k wavenumber
Absorptive particles
Complex refractive index of aerosol species
Complex refractive index, wavelength, and particle radius are important parameters for carrying out Mie-scattering calculations.
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dd
RII scat 2
0)(
1
222
2
0 0
)12(2
sin
l ll
scatscat
balk
ddd
d
Differential cross-section for the scattering angle of
Total cross-section for Mie-scattering of a single particle
Extinction efficiency2a
Q scatscat
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Size parameter dependence of the total cross-section
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Size distribution for typical aerosol models
3
1
2
0
21
2n n
n
n
n rrNrd
dN log
)/log(exp
)(log)(logLognormal size distribution
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Calculation of wavelength dependence of extinction coefficient for typical aerosol models 典型的なエアロゾルモデルに対する消散係数の波長依存性の計算
22 )(),(log
)(log)(max
min rrQrd
rddNrQr ext
extext
r
rM
3
1
2
0
log)/log(
21exp
)(log2)(log n n
n
n
n rrNrd
dN
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Q1 大気汚染の原因となる物質にはどのようなものがあるか。Describe important substances that cause air pollution.
Q2 エアロゾルとは何か。日常生活にどのような影響を与えているか。What are aerosol particles? What influences do they have in our daily life?
Q3 エアロゾルが地球の放射収支に与える影響を直接効果、間接効果を含めて説明しなさい。Discuss how aerosols impact the Earth's radiation budget, including both direct and indirect effects.
Q4 本日の講義から得られた新しい考え方や知識 (なるべくたくさん) What's new -New ideas and knowledge thorough this lecture?
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