1. and a head sensor on a sun tracker What is PANDORA? Pandora is a small spectrometer system, which we have been developing since 2006. We now have over 30 Pandoras. It consists of … a “miniature” spectrometer Measures sun and sky radiance from 280 to 525 nm in 0.5 nm steps with a 1.6 o field of view. Products: NO 2, H 2 O, O 3, SO 2, HCHO, and aerosol properties. Grey = under development O 3 : 3 DU accuracy and 1 DU precision NO 2 : 0.1 DU accuracy and 0.01 DU precision Temperature controlled

2. The Pandora optical heads are shown mounted on a shelf. The yellow boxes contain the spectrometer and computer in a temperature controlled environment at 25C to within 1 degree by internal thermoelectric cooling The optical head can track the sun to obtain total column amounts of trace gases or look at the sky to obtain altitude profiles of O 3 and NO 2 Pandora Setup

3. Where is Pandora Used? Pandora is designed for field campaigns, such NASA’s Discover-AQ (a four-year campaign to improve the use of satellites to monitor air quality for public health and environmental benefit) and long-term measurements. Instruments have been installed in Korea, New Mexico, Langley-VA, Houston-TX, Helsinki, Goddard, SERC-MD, NASA-HQ, Boulder Colorado, 4-Corners, NM, and at Tenerife. Additional Pandoras are being built for NOAA Boulder Colorado (Bob Evans), Wallops Island (John Moisan), St Louis (Jack Fishman), and Harvard Smithsonian (Kelly Chance). Key Features 1)Measurements every 40 Seconds 2)High precision and accuracy 3)Unattended Operation 3

4. Examples of O 3 Column Amounts 4/10/2014OWV group meeting4

5. Examples of NO 2 Column Amounts 4/10/2014OWV group meeting5

6. Pandora Measurements of Ozone Profiles Compared with O 3 Balloon Sondes Smith Point, Texas on Sept 18 and 26, 2013 Pandora O 3 Profile Balloon Sonde O 3 Profile Notice the profile agreement in the Troposphere

7. 7 Pandora Measurements of NO 2 Profiles Smith Point, Texas on Sept 25, 2013 Polluted Wind Blowing from the Land Clean Air Blowing from the Gulf of Mexico Vertical resolution better than 25 m for NO 2 profiles

8. 8 Profiles of NO 2 Compared with Aircraft Measurements Discover-AQ NO 2 profiles derived from Pandora direct-sun and MAXDOAS observations over Fresno, California on 18-Jan-2013 Comparison of Pandora retrieval to aircraft (P3B) measured NO 2 profile (Fresno California). Variation of Boundary Layer NO 2 Profile