1. Pat Arnott, Dec 2003 DRI Aerosol Optics at the SGP CART Site and on the Twin Otter Pat Arnott, John Walker, Hans Moosmüller Desert Research Institute University of Nevada Reno NV Objectives: Quantify aerosol scattering and absorption at the ground and aloft. Link laboratory (Reno Aerosol Optics Experiment), ground-based, and aircraft measurements to assist with understanding instrument issues. Use complementary measurements from diverse instruments to compare and contrast opinions about aerosol optics. Use closure in the form of Extinction = Scattering + Absorption where possible to sort good and bad measurements.

2. Pat Arnott, Dec 2003 CART SITE IN-SITU AEROSOL OPTICS Absorption DRI Photoacoustic: 532 nm and 1047 nm.** DRI 7 wavelength Aethalometer 370, 470, 521, 590, 660, 880, 950 nm. UNIV. WA Custom PSAP 467, 530, 660 nm. NOAA Standard PSAP 550 nm.* Scattering NOAA TSI Nephelometer 450, 550, 700 nm. (Backscatter fraction as well.)* DRI Integrating Sphere Nephelemeter, 532 nm. Laser-based instrument with forward truncation angle ≈ 1 deg** THERMOANDERSON MIE instrument operating at 2 wavelengths. Extinction DRI Cavity Ringdown Instrument, 532 nm. Modified from RAOS for more effective aerosol sampling, and to reduce the need for purge flow corrections.** * Instruments at both the GIF and AOS trailer (standard setup). ** Instruments for closure comparison at 532 nm.

3. Pat Arnott, Dec 2003 Aerosol Optics Instruments at the SGP CART SITE DRI PA absorption at 532 nm, 1047 nm, CRD, and IS Neph and PSAPs

4. Pat Arnott, Dec 2003 Aerosol Absorption at the CART site: Time Series. Event around day 143 UTC most well-defined and agreed upon. 23 May 2003.

5. Pat Arnott, Dec 2003 Aerosol Absorption at the CART site: Scatter Plots. Message: Agreement among PSAP’s, and between PA is less good than we have seen in the past.

6. Pat Arnott, Dec 2003 Aerosol Absorption at the CART site: Scatter Plots. Message: Agreement among PSAP’s, and between PA is less good than we have seen in the past.

7. Pat Arnott, Dec 2003 Aerosol Optics Closure at the CART site: 532 nm Time Series

8. Pat Arnott, Dec 2003 Aerosol Optics Closure at the CART site: 532 nm Time Series of Absorption (Photoacoustic) and Scattering (DRI IS)

9. Pat Arnott, Dec 2003 Aerosol Optics Closure at the CART site: 532 nm Scatter Plot

10. Pat Arnott, Dec 2003 Aerosol Scattering at the CART site: 532 nm, DRI IS and TSI Interpolated Data (10 um cut on AOS, no cut on DRI).

11. Pat Arnott, Dec 2003 Aerosol Scattering at the CART site: 532 nm, DRI IS and TSI Interpolated Data

12. Pat Arnott, Dec 2003 Aerosol Scattering at the CART site: Angström Exponent for Selected DRI Neph RH.

13. Pat Arnott, Dec 2003 Aerosol Scattering at the CART site: 532 nm, DRI IS and TSI Interpolated Data Differences as a Function of Angstrom Exponent

14. Pat Arnott, Dec 2003 532 nm Single Scatter Albedo Histograms SGP CART SITE

15. Pat Arnott, Dec 2003 IN-SITU AEROSOL OPTICS ALOFT Absorption DRI Photoacoustic: 676 nm. UNIV. WA Custom PSAP 467, 530, 660 nm. Scattering UNIV. WA TSI NEPH 450, 550, 700 nm, and Humidification System. (More details from the UW). NASA AMES Reciprocal Nephelometer 676 nm. Extinction NASA AMES Cavity Ringdown Instrument, 676 nm.

16. Pat Arnott, Dec 2003 Photoacoustic Measurements of Aerosol Light Absorption at 676 nm from the Twin Otter Aircraft

17. Pat Arnott, Dec 2003 CIRPAS Twin Otter at the Ponca City OK airport, 2003

18. Pat Arnott, Dec 2003 Otter over GIF Trailer, Photo courtesy Yin-Nan Lee, BNL

19. Pat Arnott, Dec 2003 School of Hard Rocks

20. Pat Arnott, Dec 2003 Eductor System for Aerosol Delivery

21. Pat Arnott, Dec 2003 Plane Inlet

22. Pat Arnott, Dec 2003 Scattering loss in the sampling line as a function of flow rate.

23. Pat Arnott, Dec 2003 Pancakes Layers of Asian Smoke from the Air 27 May 3 (Photo by Roy the Co-pilot)

24. Pat Arnott, Dec 2003 May 27th: Layers Aloft Aerosol Optics at 660 nm.

25. Pat Arnott, Dec 2003 May 27th: Layers Aloft Aerosol Light Absorption at 660 nm and 676 nm

26. Pat Arnott, Dec 2003 Example of Photoacoustic Data Quality Metric Aloft.

27. Pat Arnott, Dec 2003 A Single Layer was observed on 28 May 2003

28. Pat Arnott, Dec 2003 Time series of light absorption from the 28th of May

29. Pat Arnott, Dec 2003 To Do And Possible Papers CART SITE: ‘Validate’ the TSI and DRI neph comparisons. Compare light absorption values with the UW PSAP that was in the GIF trailer. (Hourly averages of all DRI Aerosol Optics Data are in the archive) AIRCRAFT: Comb cabin files for aircraft altitude and ambient pressure versus time to better assign an ambient Babs value to the photoacoustic data. (raw data and draft 2 minute time average data are in the archive.) (Collective Job) Assign time intervals to all legs, and do leg averages. Combine with CART SITE data when the aircraft was low over the site to compare data. PAPERS 1.Instrument comparison from CART SITE data. 2. Measurements of aerosol optics aloft (instrument comparison and case studies), especially light absorption.

30. Pat Arnott, Dec 2003 Thanks for your attention…