Transcript Aura NO2 talk - Dalhousie University

Advances in Applying Satellite Remote Sensing to
the AQHI
Randall Martin, Dalhousie and Harvard-Smithsonian
Aaron van Donkelaar, Akhila Padmanabhan, Dalhousie University
Lok Lamsal, Dalhousie U  NASA Goddard
45th CMOS Congress, Victoria
7 June 2011
Large Regions Have Insufficient Measurements for AQHI
Measurement
Locations of NAPS Sites
Southern Ontario
Major Nadir-viewing Space-based Measurements
of AQHI Species
Solar Backscatter, Thermal Infrared, Active
Sensor GOES
Imager
Platform GOES
(launch) (varied)
MISR
Terra
(1999)
SCIAMACHY
TES
OMI
Aqua
(2002)
Envisat
(2002)
Aura
(2004)
1:30
10:00
1:45
Equator
Crossing
n/a
Typical Res
(km)
4x4
18x18
10x10
60x30
8x5
Global Obs
(w/o clouds)
n/a
7
2
6
n/a
X
X
X
PARASOL CALIOP GOME
-2
PARASOL CALIPSO
(2004)
IASI
MetOp
(2006)
1:30
1:30
9:30
>24x13
18x16
40x40
80x40 12x12
1
1
n/a
1
X
X
X
1
X
NO2
X
X
X
Ozone
X
X
X
Aerosol
10:30
MODIS
X
0.5
X
General Approach to Estimate Surface Concentrations
NO2 Column
Model Profile
In Situ
GEOS-Chem
 SM 
SO   O 


 M
S → Surface Concentration
Ω → Tropospheric column
Ground-Level Afternoon NO2 Inferred From OMI for 2005-2007
NO2 [ppbv]
Lok Lamsal
Ground-Level NO2 Inferred From OMI for 2005
Works in Near-Real-Time!
Values Estimated Using Monthly NO2 Profiles for Different Year (2006)
Temporal Correlation with In Situ Over 2005
×In situ
—— OMI
Insignificant change in results if profiles are daily coincident
values from 2005
Lok Lamsal
Aerosol Most Visible over Dark Targets
Pollution haze over East Coast
Dust off West Africa
Aerosol Optical Depth (AOD) from MODIS and MISR over 2001-2006
MODIS
MODIS
r = 0.40
vs. in-situ PM2.5
1-2 days for global coverage (w/o
clouds)
AOD retrievals at 10 km x 10 km
Requires assumptions about surface
reflectivity
MISR
6-9 days for global coverage (w/o
clouds)
AOD retrievals at 18 km x 18 km
MISR
r = 0.54
vs. in-situ PM2.5
0
0.1
0.2
AOD [unitless]
0.3
Simultaneous retrieval of surface
reflectance and aerosol optical
properties
van Donkelaar et al., EHP, 2010
July
Agreement With AERONET Varies with Surface Type
MODIS
MISR
9 surface types, defined by monthly mean surface albedo ratios,
evaluation against AERONET AOD
van Donkelaar et al., EHP, 2010
Combined AOD from MODIS and MISR
Rejected Retrievals for Land Types with Monthly Error vs AERONET >0.1 or 20%
0.25
Combined
MODIS/MISR
r = 0.63 (vs. in-situ PM2.5)
0.2
0.15
0.1
0.05
MODIS
r = 0.40
MISR
r = 0.54
(vs. in-situ PM2.5)
(vs. in-situ PM2.5)
0
van Donkelaar et al., EHP, 2010
AOD [unitless]
0.3
Significant Agreement with Coincident In situ Measurements
Used GEOS-Chem to Calculate AOD/PM2.5 (η)
0.40
MISR AOD
0.54
Combined AOD
0.63
Combined PM2.5
0.77
Satellite-Derived [μg/m3]
MODIS AOD
Satellite
Derived
In-situ
In-situ PM2.5 [μg/m3]
van Donkelaar et al., EHP, 2010
Annual Mean PM2.5 [μg/m3] (2001-2006)
r
Error Sources in Satellite-Derived PM2.5
Model
•
•
Affected by aerosol optical
properties, concentrations, vertical
profile, relative humidity
Most sensitive to vertical profile
[van Donkelaar et al., 2006]
Evaluate vs Calipso lidar obs
•
•
Estimate error from bias in
profile and AOD ±(1 μg/m3 + 15%)
Contains 68% (1 SD) of North
American data
•
Error limited to 0.1 + 20% by
AERONET filter
Implication for satellite PM2.5
determined by AOD/PM2.5
•
Satellite-Derived [μg/m3]
•
Satellite
In-situ PM2.5 [μg/m3]
van Donkelaar et al., EHP, 2010
USA Today: Hundreds Dead from Heat, Smog,
Wildfires in Moscow
9 Aug 2010: “Deaths in Moscow have doubled
to an average of 700 people a day as the
Russian capital is engulfed by poisonous smog
from wildfires and a sweltering heat wave, a top
health official said Monday.”
MODIS/Aqua: 7 Aug 2010
Spatial and Temporal Variation in Satellite-Based PM2.5
during Moscow 2010 Fires
van Donkelaar et al., AE, submitted
Satellite-Based PM2.5 Insensitive to Emission Inventory
Daily Meteorology More Important
Different Emission Inventories
GEOS-Chem Calculation of AOD / PM2.5
van Donkelaar et al., AE, submitted
Application of Satellite-based Estimates to Moscow
Smoke Event
During Fires
Before Fires
r2 =0.85, slope=1.06
MODIS-based
In Situ from PM10
In Situ PM2.5
van Donkelaar et al., submitted
Growing Confidence in Application of Satellite
Remote Sensing for PM2.5 and NO2
• Simple Method for Near-Real-Time Estimates of Ground-Level NO2
• Satellite-based PM2.5 Estimate for Long-Term and Extreme Events
Ongoing Work
• Develop daily PM2.5 estimate for Canada
• Improve spatial resolution from 10 km to 3 km
• Evaluate AOD/PM2.5 ratio
Acknowledgements:
Environment Canada, Health Canada, NASA