Advances in Applying Satellite Remote Sensing to Advances in Applying Satellite Remote Sensing to the AQHIthe 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 Large Regions Have Insufficient Measurements for AQHI MeasurementMeasurement
Locations of NAPS Sites
Southern Ontario
Major Nadir-viewing Space-based Measurements Major Nadir-viewing Space-based Measurements of AQHI Speciesof AQHI Species
Sensor GOES Imager
MISR MODIS SCIA-MACHY
TES OMI PARASOL CALIOP GOME-2
IASI
Platform (launch)
GOES (varied)
Terra Aqua
(1999) (2002)
Envisat (2002)
Aura
(2004)
PARASOL (2004)
CALIPSO MetOp
(2006)
Equator Crossing
n/a 10:30 1:30 10:00 1:45 1:30 1:30 9:30
Typical Res (km)
4x4 18x18 10x10 60x30 8x5 >24x13 18x16 40x40 80x40 12x12
Global Obs
(w/o clouds)
n/a 7 2 6 n/a 1 1 n/a 1 0.5
Aerosol X X X X X X 1 X
NO2 X X X
Ozone X X X X X
Solar Backscatter, Thermal Infrared, Active
General Approach to Estimate Surface ConcentrationsGeneral Approach to Estimate Surface Concentrations
NO2 Column
S → Surface Concentration
Ω → Tropospheric column
In Situ
GEOS-Chem
Model Profile
OM
MO S
S
Ground-Level Afternoon NOGround-Level Afternoon NO2 2 Inferred From OMI for 2005-2007 Inferred From OMI for 2005-2007
Lok LamsalNO2 [ppbv]
Ground-Level NOGround-Level NO2 2 Inferred From OMI for 2005 Inferred From OMI for 2005
Temporal Correlation with In Situ Over 2005
×In situ—— OMI
Works in Near-Real-Time!
Values Estimated Using Monthly NO2 Profiles for Different Year (2006)
Insignificant change in results if profiles are daily coincident values from 2005
Lok Lamsal
Aerosol Most Visible over Dark TargetsAerosol Most Visible over Dark Targets
Pollution haze over East Coast Dust off West Africa
Aerosol Optical Depth (AOD) from MODIS and MISR over 2001-2006Aerosol Optical Depth (AOD) from MODIS and MISR over 2001-2006
MODIS1-2 days for global coverage (w/o
clouds)
AOD retrievals at 10 km x 10 km
Requires assumptions about surface reflectivity
MISR6-9 days for global coverage (w/o
clouds)
AOD retrievals at 18 km x 18 km
Simultaneous retrieval of surface reflectance and aerosol optical properties
0 0.1 0.2 0.3AOD [unitless]
MODISr = 0.40
vs. in-situ PM2.5
MISRr = 0.54
vs. in-situ PM2.5
van Donkelaar et al., EHP, 2010
Agreement With AERONET Varies with Surface Type
9 surface types, defined by monthly mean surface albedo ratios,evaluation against AERONET AOD
MODIS
MISR
Jul
y
van Donkelaar et al., EHP, 2010
Combined AOD from MODIS and MISRCombined AOD from MODIS and MISRRejected Retrievals for Land Types with Monthly Error vs AERONET >0.1 or 20%Rejected Retrievals for Land Types with Monthly Error vs AERONET >0.1 or 20%
MODISr = 0.40
(vs. in-situ PM2.5)
MISRr = 0.54
(vs. in-situ PM2.5)
CombinedMODIS/MISR
r = 0.63 (vs. in-situ PM2.5)
0.3
0.25
0.2
0.15
0.1
0.05
0
AO
D [u
nitle
ss]
van Donkelaar et al., EHP, 2010
Significant Agreement with Coincident In situ MeasurementsSignificant Agreement with Coincident In situ MeasurementsUsed GEOS-Chem to CalculateUsed GEOS-Chem to Calculate AOD/PMAOD/PM2.52.5 ( (η)η)
SatelliteDerived
In-situ
Sat
ellit
e-D
eriv
ed
[μg/
m3]
In-situ PM2.5 [μg/m3]
Ann
ual M
ean
PM
2.5 [
μg/
m3]
(200
1-20
06)
r
MODIS AOD 0.40
MISR AOD 0.54
Combined AOD 0.63
Combined PM2.5 0.77
van Donkelaar et al., EHP, 2010
Error Sources in Satellite-Derived PMError Sources in Satellite-Derived PM2.52.5
Satellite• Error limited to 0.1 + 20% by
AERONET filter
• Implication for satellite PM2.5
determined by AOD/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
Sat
ellit
e-D
eriv
ed
[μg/
m3]
In-situ PM2.5 [μg/m3]
van Donkelaar et al., EHP, 2010
USA Today: Hundreds Dead from Heat, Smog, USA Today: Hundreds Dead from Heat, Smog, Wildfires in MoscowWildfires 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 PMSpatial and Temporal Variation in Satellite-Based PM2.52.5
during Moscow 2010 Firesduring Moscow 2010 Fires
van Donkelaar et al., AE, submitted
Satellite-Based PMSatellite-Based PM2.5 2.5 Insensitive to Emission InventoryInsensitive to Emission Inventory
Daily Meteorology More ImportantDaily Meteorology More Important
van Donkelaar et al., AE, submitted
GEOS-Chem Calculation of AOD / PM2.5
Different Emission Inventories
Application of Satellite-based Estimates to Moscow Application of Satellite-based Estimates to Moscow Smoke EventSmoke Event
Before Fires During Fires
van Donkelaar et al., submitted
MODIS-based
In Situ PM2.5
In Situ from PM10
r2 =0.85, slope=1.06
Acknowledgements:Acknowledgements: Environment Canada, Health Canada, NASA Environment Canada, Health Canada, NASA
• 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
Growing Confidence in Application of Satellite Growing Confidence in Application of Satellite Remote Sensing for PMRemote Sensing for PM2.52.5 and NO and NO22
