the be rkeley h igh spatial r esolution(behr) omi no 2 retrieval: recent trends in no 2
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AQUA. AURA. The Be rkeley H igh Spatial R esolution(BEHR) OMI NO 2 Retrieval: Recent Trends in NO 2. Ronald C. Cohen University of California, Berkeley $$ NASA . Air Quality Applications Of OMI NO 2. Key elements: total columns trends over time differences and ratios in space - PowerPoint PPT PresentationTRANSCRIPT
The Berkeley High Spatial Resolution(BEHR) OMI NO2 Retrieval: Recent Trends in NO2
Ronald C. CohenUniversity of California, Berkeley$$ NASA
AQUA
AURA
Air Quality Applications Of OMI NO2
Key elements:
• total columns
• trends over time
• differences and ratios in space
• the noontime chemical lifetime of NO2 of ~1-4hrs implies an e-folding distance of order 25km
• OH changes will be approximately equal to NO2 changes—a significant effect on lifetimes
Four Corners Power Plants: WRF-Chem
L Valin et al., Atmos. Chem. Phys. 2011
Los Angeles: WRF-Chem
OMI NO2 Riyadh
8 hours
6 hours
Deriving NO2 column densities from space-based reflectance measurements
Step 1: DOAS fit to determine slant column
Step 2: Subtract the Stratospheric contribution
Tropospheric Vertical Column Density
Summary of the NO2 retrieval process
Total Slant Column Density Stratospheric Vertical Column Density
Step 3: Convert the tropospheric slant column into a vertical column
Step 3: Convert the tropospheric slant column into a vertical column
AMFs are sensitive to • Viewing geometry• Terrain pressure and reflectivity• Shape (not magnitude) of the NO2
vertical profile• Clouds
AMF = Vertical Column Slant Column
Absorption, Scattering, and Transmission
through a cloudAbsorption and
Scattering by the surface
Atmosphere
Absorption and Scattering by aerosols and
molecules
SurfaceModified image from Richter, U Bremen
Berkeley High Resolution Retrieval (BEHR)
NASA standard BEHR Terrain pressure High-res terrain
database, center of OMI footprint
High-res terrain database, average over OMI footprint
Terrain reflectivity
Monthly 1° × 1° MODIS, 8 day 0.05° × 0.05°
NO2 profile shape
Annually 2° × 2.5° WRF-Chem, Monthly 4 × 4 km2 (CA&NV)12 x 12 km2 U.S.
Clouds OMI cloud product MODIS cloud product
Russell et al., Atmos Chem & Phys 11, 8543-8554, 2011
Terrain Reflectivity (Albedo)
NASA Standard Product June 2008
BEHR June 2008
MODIS True Color
SP NO2 June 18, 2008
OMI Monthly Albedo MODIS 8 day Albedo
Russell et al., Atmos Chem & Phys, 2011
-120.5 -120 -119.5 -119 -118.5 -11840
40.5
41
41.5
42
Terrain Reflectivity (Albedo)
Russell et al., Atmos Chem & Phys, 2011
PDF of systematic errors
Terrain Pressure
Russell et al., Atmos Chem & Phys, 2011
PDF of systematic errors
NO2 profile shape
0 0.05 0.1 0.150
0.5
1
1.5
2
2.5
3
Normalized NO2
Hei
ght (
km)
UrbanRural
Russell et al., Atmos Chem & Phys, 2011
PDF of systematic errors
The BEHR product is generally higher in urban regions and lower in rural regions than the operational products
BEHR % DifferenceStandard Product
Russell et al., Atmos Chem & Phys, 2011
Summer 2005 Russell et al., ACPD in press
molecules cm-2
Summer 2011 Russell et al., in press
molecules cm-2
Trends for select cities and power plants
Russell et al., in press
05 06 07 08 09 10 110
0.5
1
1.5
2x 10
16
Col
umn
NO 2 (m
olec
/cm
2 )
Year
Denver, CO
05 06 07 08 09 10 110
0.5
1
1.5
2x 10
16
Year
Los Angeles, CA
05 06 07 08 09 10 110
0.5
1
1.5
2x 10
16
Year
Atlanta, GA
05 06 07 08 09 10 110
0.5
1
1.5
Year
Nor
mal
ized
NO 2
All Cities
05 06 07 08 09 10 110
0.5
1
1.5
Year
Nor
mal
ized
NO 2
All Power Plants
05 06 07 08 09 10 110
2
4
6x 10
15
Year
Col
umn
NO 2 (m
olec
/cm
2 )
Intermountain, UT
05 06 07 08 09 10 110
2
4
6x 10
15
Year
Four Corners, NM
05 06 07 08 09 10 110
2
4
6x 10
15
Year
Seminole, FL
–– Weekdays
- - Weekends
–– All days
05 06 07 08 09 10 110
0.5
1
1.5
2x 10
16
Col
umn
NO 2 (m
olec
/cm
2 )
Year
Denver, CO
05 06 07 08 09 10 110
0.5
1
1.5
2x 10
16
Year
Los Angeles, CA
05 06 07 08 09 10 110
0.5
1
1.5
2x 10
16
Year
Atlanta, GA
05 06 07 08 09 10 110
0.5
1
1.5
Year
Nor
mal
ized
NO 2
All Cities
05 06 07 08 09 10 110
0.5
1
1.5
Year
Nor
mal
ized
NO 2
All Power Plants
05 06 07 08 09 10 110
2
4
6x 10
15
Year
Col
umn
NO 2 (m
olec
/cm
2 ) Intermountain, UT
05 06 07 08 09 10 110
2
4
6x 10
15
Year
Four Corners, NM
05 06 07 08 09 10 110
2
4
6x 10
15
Year
Seminole, FL
Trends in cities are similar while trends at power plants are more variable05 06 07 08 09 10 11
0
0.5
1
1.5
2x 10
16
Col
umn
NO 2 (m
olec
/cm
2 )
Year
Denver, CO
05 06 07 08 09 10 110
0.5
1
1.5
2x 10
16
Year
Los Angeles, CA
05 06 07 08 09 10 110
0.5
1
1.5
2x 10
16
Year
Atlanta, GA
05 06 07 08 09 10 110
0.5
1
1.5
Year
Nor
mal
ized
NO 2
All Cities
05 06 07 08 09 10 110
0.5
1
1.5
YearN
orm
aliz
ed N
O 2
All Power Plants
05 06 07 08 09 10 110
2
4
6x 10
15
Year
Col
umn
NO 2 (m
olec
/cm
2 ) Intermountain, UT
05 06 07 08 09 10 110
2
4
6x 10
15
Year
Four Corners, NM
05 06 07 08 09 10 110
2
4
6x 10
15
Year
Seminole, FL
Russell et al., in press
47 cities, 23 power plants!
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-50
-40
-30
-20
-10
0
10
2005 – 2011 reductions in urban regions of the US are similar (–32 ± 7%).
Russell et al., in press
The impact of the economic recession on emissions is observed by OMI
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
2005 – 2007
Russell et al., in press
The impact of the economic recession on emissions is observed by OMI
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
2005 – 2007
2007 – 2009
Russell et al., in preparation
2005 – 2007
The impact of the economic recession on emissions is observed by OMI
Russell et al., in press
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-15
-10
-5
0
5
2005 – 2007
2007 – 2009
2009 – 2011
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-50
-40
-30
-20
-10
0
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-50
-40
-30
-20
-10
0
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-50
-40
-30
-20
-10
0
-120 -110 -100 -90 -80 -7025
30
35
40
45
50
-50
-40
-30
-20
-10
0
Weekdays: –34 ± 8% Weekends: –27 ± 10%
Reductions on weekdays are larger than those on weekends due to reductions in diesel traffic
2005 – 2007 2007 – 2009 2009 – 2011Weekday – 6 ± 4% – 9 ± 4% – 4 ± 4%Weekend – 7 ± 5% – 6 ± 7% – 1 ± 7%
Russell et al., in press
Conclusions
• The BEHR product reduces biases in the NO2 column due to coarse resolution terrain and profile parameters. We can make it available upon request, [email protected].
• Analysis of 2005–2011 trends for cities and power plants in the US show how improved vehicle technology and the economic downturn have influenced emissions.
Ashley Russell Luke Valin(PhD May 2012) (PhD soon)
Thank you!
A.R. Russell, et al, Trends in OMI NO2 observations over the United States: Effects of emission control technology and the economic recession, ACPD. in press June 2012.L.C. Valin, et al, Effects of model resolution on the interpretation of satellite NO2 observations, ACP. 11, 11647-11655, 2011 A.R. Russell, et al., A high spatial resolution retrieval of NO2 column densities from OMI: Method and Evaluation, ACP, 11, 8543-8554, 2011.L.C. Valin, et al., Observation of slant column NO2 using the super-zoom mode of AURA OMI, AMT, 4, 1929-1935, 2011.A.K. Mebust,, Characterization of wildfire NOx emissions using MODIS fire radiative power and OMI tropospheric NO2 columns , ACP. 11, 5839-5851, 2011.
R.C. Hudman, et al., Interannual variation in soil NOx emissions observed from Space, ACP. 10, 9943-9952, 2010.
Update: Trends in urban regions of CA, 2005-2011
- 44%
- 30%- 36%
- 30%
Russell et al., 2010 (updated)
Beer-Lambert Law:
I = Io e - σ ℓ N
ℓ
SAMPLE(N)LIGHT SOURCE (Io)
DETECTOR (I)
POLISHEDMIRROR
PARTICLES
CLOUDS
Entangled
MOLECULES
WRF-CHEM 1km – 4-Corners Plume
NO2 column OH Column
Large Area+Urban Sources in WRF-Chem
e-kx; x = ut; τ=k-1
NOx LifetimeBy Mass
By Decay Gradient
Integrated Observation
Resolved Observation
τ=Mobs / Erate