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Mapping Surface NO 2 and PM 2.5 from Satellite Observations Randall Martin, Dalhousie University with contributions from Aaron van Donkelaar, Dalhousie.

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Presentation on theme: "Mapping Surface NO 2 and PM 2.5 from Satellite Observations Randall Martin, Dalhousie University with contributions from Aaron van Donkelaar, Dalhousie."— Presentation transcript:

1 Mapping Surface NO 2 and PM 2.5 from Satellite Observations Randall Martin, Dalhousie University with contributions from Aaron van Donkelaar, Dalhousie U Lok Lamsal, Dalhousie U  NASA Goddard Colin Lee, U Toronto  Dalhousie U Environment Canada, Downsview 16 Jan 2011

2 Major Nadir-viewing Space-based Measurements of Air Quality (Not Exhaustive) SensorGOES Imager MOPITTMISRMODISAIRSSCIA- MACHY TESOMIPARA- SOL CALIOPGOME- 2 IASIVIIRS Platform (launch) GOES (varied) Terra Aqua (1999) ( 2002) Envisat (2002) Aura (2004) PARA- SOL (2004) Calipso (2006) MetOp (2006) NPP (2011) Equator Crossing n/a 10:30 1:3010:001:451:30 9:301:30 Typical Res (km) 4x422x2218x1810x1014 x1460x308x5>24x 13 18x1640x4080x4012 x12 6x6 Global Obs n/a n/a AerosolXXXXXXXXX NO 2 XXX HCHOXXX COXXXXX OzoneXXXXX SO 2 XXXX NH 3 XX Solar Backscatter & Thermal Infrared

3 General Approach to Estimate Surface NO 2 Concentration NO2 Column S → Surface Concentration Ω → Tropospheric column In Situ Model Model Profile Method: Solar backscatter Scattering by Earth surface and atmosphere   Idealized NO 2 absorption spectrum  

4 Afternoon Ground-Level NO 2 Inferred From OMI for Lok Lamsal NO 2 [ppbv]

5 Ground-Level NO 2 Inferred From OMI for 2005 Temporal Correlation with In Situ Over 2005 ×  In situ —— OMI Works in Near-Real-Time! Values Estimated Using Monthly NO 2 Profiles for Different Year (2006) Insignificant change in results if profiles are daily coincident values from 2005 Lok Lamsal

6 Infer Ground-level NO 2 Between Monitors Using Empirical Column-to-Surface Ratio from In Situ Monitors Automatically Corrects for Bias in Satellite Column Lee et al., ACP, 2011 Passive Sites Permanent Sites

7 Combine both information sources (Model and In Situ) Explore with PM 2.5 inferred from MODIS & MISR AOD

8 RAW Has Significant Agreement with Long-Term ( ) In situ Measurements Satellite Derived In-situ Satellite-Derived [ μ g/m3] In-situ PM 2.5 [μg/m 3 ] Annual Mean PM 2.5 [ μ g/m 3 ] ( ) r MODIS AOD0.39 MISR AOD0.39 Combined AOD0.61 Combined PM van Donkelaar et al., EHP, 2010

9 Significant Association of Long-Term PM 2.5 Exposure with Cardiovascular Mortality Crouse et al., EHP, submitted

10 RAW Has Limited Daily Skill Mean daily error can exceed 100%! Aaron van Donkelaar

11 Climatological Monitor Correction (CMC) to Correct Bias Regress 90-day running comparisons Make correction surface using IDW 2 weighted average

12 CMC Improves Daily Accuracy Reduces effects of climatological bias Reduces mean daily error to 40-60% Aaron van Donkelaar

13 IDW Inverse Distance Weighting of Satellite Estimate Improves Skill by Reducing Spatial Noise Regional mean daily error now ~40% Aaron van Donkelaar


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