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UV Aerosol Product Status and Outlook Omar Torres and Changwoo Ahn OMI Science Team Meeting Outline -Status -Product Assessment OMI-MODIS Comparison OMI-Aeronet.

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Presentation on theme: "UV Aerosol Product Status and Outlook Omar Torres and Changwoo Ahn OMI Science Team Meeting Outline -Status -Product Assessment OMI-MODIS Comparison OMI-Aeronet."— Presentation transcript:

1 UV Aerosol Product Status and Outlook Omar Torres and Changwoo Ahn OMI Science Team Meeting Outline -Status -Product Assessment OMI-MODIS Comparison OMI-Aeronet Comparison OMI-AATS Comparison -Summary and Conclusions Baltimore, June 6, 2007

2 Status Products: - Aerosol Extinction and Absorption Optical Depth 388 nm -Also reports values at 354 and 500 nm (converted) Validation Analysis -Comparisons to other satellite products (MODIS, MISR) (Ahn, et al, 2007) -Comparison to AERONET observations (Torres et al, 2007) -Comparison to Airborne observations (Livingston et al, 2007) Data availability -Publicly released (L2, L2G)

3 (A) Jan 2, 2007, biomass burning(B)May 14, 2006, Pollution Aerosols (C) March 10, 2006, Asian dust (D) August 15, 2006, Saharan dust OMI Aqua-MODIS comparison of retrieved AOD

4 Aeronet Sites used in the Analysis Site Location Aerosol type Alta_Floresta Agoufou Banizombou IER-Cinzana Ougadougou Mongu Forth Crete Blida Saada Dakar Kanpur Dhadnad Hamim Mukdahan XiangHe GSFC Halifax Bratts_Lake Bondville CARTEL Cove HJAndrews MD Science Center MVCO SERC Sioux_Falls UCSB Wallops 9S 56W 15N 1W 13N 2E 13N 5W 12N 1W 15S 23E 35N 25E 36N 2E 31N 8W 14N 16W 26N 80E 25N 56E 22N 54E 16N 104E 39N 116E 38N 76W 44N 63W 50N 104W 40N 88W 45N 71W 36N 75W 44N 122W 39N 76W 41N 70W 38N 76W 43N 96W 34N 119W 37N 75W smoke smoke, dust dust dust, smoke smoke dust, pollution dust dust,smoke dust,smoke,pollution dust smoke,pollution dust,smoke,pollut. weakly absorbing

5 13 sites 2 years (2005-6) 374 points OMI-UV Aeronet Comparison Weakly-absorbing aerosols 0.03~0.05 Bias Reasonable agreement for clear conditions Poor statistics!

6 OMI-Aeronet Comparison Desert Dust Aerosols 4 sites 2years 2005-6 256 points Good Statistics High Noise Level, Aerosol layer height? 0.3 bias

7 OMI-Aeronet Comparison Pollution Aerosols 2 sites 101 points Reasonable agreement Bias of ~0.2 at low AOD’s

8 AOD Comparisons, OMI - MODIS - AATS INTEX-B/MILAGRO, 2006 MODIS Aura/OMI overpass ~15 minutes after Aqua at 20:13 UT J31 low altitude transect J31 flight track color coded by altitude MODIS 10x10 km 2 OMI 13x24km 2 True Color Image (Aqua), 10 March, 19:55-20:00 UT (Phil Russell, NASA, AMES)

9 AOD Comparisons, OMI - MODIS - AATS INTEX-B/MILAGRO, 10 March 2006 J31 low altitude transect 19:40-20:01 UT OMI MW MODIS OMI UV 84 43 17 5 1 J31 low altitude transect 19:40-20:01 UT OMI % cloud MODIS % cloud 2 2 Geo-collocation difference in OMI-UV and MW retrievals

10 10 March 2006 (over water) Case 1 OMI MW & UV AOD retrievals exceed MODIS and AATS values. (Prelim) Milagro Airborne AOD measurements vs OMI & MODIS OMI near-UV retrieval quality flags indicate poor retrievals and suggest possible cloud contamination; retrievals yield enhanced AODs

11 Photo from DC-8 over Mexico City, 19 Mar 2006 Courtesy of Cam McNaughton (Univ. of Hawaii)

12 MW UV T2 T1 J31 track OMI overpass: 20.11 UT 19 March 2006 (over land) J31 ~450-750 m above surface “Visibility poor; eyes burning in cockpit…” Larger OMI MW AOD retrievals over land likely due to incorrect surface albedo assumption. highest quality AATS AOD: high variability, flat depend. (Prelim) Phil Russell

13 Assessment of OMI-UV Absorption Retrievals during MILAGRO campaign OMI-UV Aerosol Absorption Optical Depth agrees well with AATS Inferred Absorption Optical Depth Spectral on March 19, 2006 (Phil Russell)

14 Comparison of OMI and AERONET Retrievals of Single Scattering Albedo Smoke and Pollution Aerosols RMS: 0.03 Dust Aerosols RMS: 0.02

15 OMI-Aeronet Comparison of Absorption Optical Depth Dust Aerosols RMS: 0.02

16 -Severe sub-pixel cloud contamination affects retrieval of extinction optical depth for weakly absorbing aerosols -Reasonable agreement for absorbing aerosols -In the presence dust-smoke mixtures, OMI AOD’s are over- estimated -In general a bias of about 0.2 ~0.3 is observed with respect to AERONET observations -Reasonable agreement in aerosol absorption parameters (AAOD and SSA) -Reprocessing of Collection 3 data will start in summer-07 -Preliminary analysis indicate that in Collection 3 data the AOD bias will decrease Summary and Conclusions


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